redact: replace psarc/Rocksmith/official DLC references with neutral terms

docs: clarify plugin licensing and metadata access
Signed-off-by: barlind <tobias@barlind.se>
2026-09-11 06:54:31 +00:00 · 2026-06-18 00:48:09 -07:00 · 2026-06-18 00:41:59 -07:00 · 2026-06-18 00:41:56 -07:00 · 2026-06-18 00:41:10 -07:00 · 2026-06-18 00:40:43 -07:00
37 changed files with 2830 additions and 988 deletions
@@ -0,0 +1,42 @@
+# `.claude/` — Claude Code surfaces
+
+This directory holds [Claude Code](https://claude.ai/code) artifacts: skills, rules, and subagents. **Other AI tools** (Cursor, Copilot, Codex, Aider) should read [`AGENTS.md`](../AGENTS.md) instead — `.claude/` is Claude-Code-specific.
+
+## Layout
+
+```text
+.claude/
+├── agents/                            Subagents (invoked via @<name>)
+│   └── slopsmith-reviewer.md          Plugin-aware code review
+├── rules/                             Globs-scoped behaviour rules
+│   └── plugin-author.md               Rules that fire when editing plugins/**
+├── skills/                            Skills (description triggers auto-invocation)
+│   ├── plugin-scaffold/SKILL.md       Generate a new plugin skeleton
+│   ├── plugin-validate/SKILL.md       Validate a plugin.json against the schema
+│   └── speckit-*/                     Spec-kit skills (auto-generated; don't edit)
+├── settings.json                      Repo defaults (no hooks enabled by default)
+└── README.md                          You are here
+```
+
+## Conventions
+
+- **Spec-kit owns `skills/speckit-*`.** Don't edit those manually — they're regenerated by the spec-kit installer (`.specify/`).
+- **Repo skills live alongside spec-kit skills** in `skills/`. New skills should have a kebab-case directory name and a `SKILL.md` with YAML frontmatter.
+- **Hooks are off by default.** Hooks in `.claude/settings.json` run in every contributor's Claude Code session — enabling one imposes work on everyone. The settings file ships with `hooks: {}` and a commented example so anyone who wants to opt in can copy it locally.
+- **Subagent invocation.** Use `@slopsmith-reviewer` to invoke a subagent explicitly. Plain auto-routing isn't currently configured.
+
+## Adding a new skill
+
+1. Create `.claude/skills/<kebab-name>/SKILL.md`.
+2. YAML frontmatter must include `name` (must match directory) and `description` (must read like a sentence — Claude Code matches the description against user intent for auto-invocation).
+3. Body: instructions Claude follows when the skill triggers. Keep it concrete and short — long skills bit-rot.
+
+## Adding a new rule
+
+1. Create `.claude/rules/<topic>.md`.
+2. Frontmatter may include `globs:` (array of glob patterns scoping when the rule applies). Without `globs`, the rule loads for every session.
+3. Body: terse, imperative guidance — "always do X", "never do Y", "if you see Z, …".
+
+## Why so little here?
+
+The maintainer's personal Claude Code rules (context-mode routing, RTK, `@git-worker`, etc.) deliberately do **not** live in this repo. Those are user-global concerns in `~/.claude/` — keeping them out of the repo keeps the shared surface lean and makes the repo equally useful to contributors using Cursor, Copilot, plain editors, etc.
@@ -0,0 +1,68 @@
+---
+name: slopsmith-reviewer
+description: Plugin-aware code reviewer for Slopsmith. USE WHEN reviewing plugin changes, auditing a plugin against the manifest contract, checking that a plugin uses capability metadata / load_sibling / context["log"] correctly, or verifying that a `plugin.json` matches the schema and the directory it lives in. Returns a structured pass/fail report with specific file:line citations.
+tools: Read, Grep, Glob, Bash
+model: sonnet
+---
+
+# slopsmith-reviewer
+
+Plugin-aware reviewer for Slopsmith. Use when reviewing a plugin's code or manifest. Does **not** duplicate the built-in `peer-review` skill — focus is narrow: the plugin contract surface defined in [`docs/PLUGIN_AUTHORING.md`](../../docs/PLUGIN_AUTHORING.md) and enforced by [`schema/plugin.schema.json`](../../schema/plugin.schema.json), including `capability-pipelines.v1` metadata, and `tests/test_plugin_schema.py`.
+
+## When to invoke
+
+Use this agent when the user asks to:
+- "review this plugin"
+- "audit `plugins/<id>/`"
+- "check the manifest"
+- "verify the plugin uses load_sibling / logging correctly"
+- "lint plugin"
+
+Do **not** invoke for general code review — use the built-in `peer-review` skill for that.
+
+## Inputs
+
+The user typically points at a directory: `plugins/<id>/`. If no directory is given, ask which plugin to review.
+
+## Checklist (every review must run these)
+
+Run each item; structure the output as `PASS` / `FAIL` / `N/A` with file:line citations.
+
+1. **Manifest exists and validates.** `plugins/<id>/plugin.json` exists. Run:
+   ```bash
+   python -c "import json,jsonschema; s=json.load(open('schema/plugin.schema.json')); jsonschema.validate(json.load(open('plugins/<id>/plugin.json')), s); print('OK')"
+   ```
+2. **Manifest `id` matches the directory name.** `tests/test_plugin_schema.py::test_in_tree_manifest_id_matches_directory` enforces this — but call it out in review.
+3. **Declared plugin files exist.** For plugin-root-relative file fields (`script`, `routes`, `tour`, `settings.html`), `test -f plugins/<id>/<path>` must succeed.
+4. **License is on the curated allowlist** if present. Cross-check `plugin.json.license` against the SPDX list in [`CONTRIBUTING.md`](../../CONTRIBUTING.md) "Plugin licensing".
+5. **`type: "visualization"` ↔ `window.slopsmithViz_<id>` factory.** If `type == "visualization"`, grep `script` for the factory declaration.
+6. **Backend logging.** Grep `plugins/<id>/*.py` for `print(`, `traceback.print_exc(`, `logging.getLogger(`. Suggest `context["log"]` replacements.
+7. **Sibling imports.** If `routes.py` exists and grep finds bare `from <module> import` for any sibling Python file in the plugin dir, flag and recommend `context["load_sibling"]`.
+8. **Frontend IIFE.** If `script` exists, check the top of the file isn't running top-level statements that leak to global scope. Wrapping in `(function () { 'use strict'; ... })();` is the convention.
+9. **Capability-first frontend integration.** If the script wraps host globals or polls another plugin's globals, flag it as a capability gap unless the PR explicitly documents why no active domain can model the integration yet.
+10. **`localStorage` prefix.** Grep for `localStorage.` usage; keys must start with `<plugin_id>`.
+11. **Server-file allowlists are safe.** `settings.server_files` and `diagnostics.server_files` entries are relpaths under `context["config_dir"]`, not files under the plugin directory. Check for no leading `/`, no `..`, no backslashes, no `//`, no `./`, and no leading dotfiles. The schema enforces this but call it out.
+
+## Output format
+
+```text
+plugin-review: <plugin_id>
+=========================
+1. manifest validates                 PASS
+2. id matches directory               PASS
+3. declared plugin files exist        FAIL — script lists "missing.js" but plugins/<id>/missing.js is absent
+...
+
+Total: 10 PASS / 1 FAIL / 1 N/A
+Action items:
+- Remove the dangling script entry, or create the file.
+- Replace `print(...)` calls at routes.py:42, routes.py:88 with `context["log"].info(...)`.
+```
+
+If everything passes, say so explicitly — silent success is unhelpful in a review context.
+
+## Out of scope
+
+- General code style / formatting — use the built-in `peer-review`.
+- Bug-hunting beyond the plugin contract.
+- Suggesting major refactors. Stay on contract compliance.
@@ -0,0 +1,49 @@
+---
+name: plugin-author
+description: Rules that apply when editing files under plugins/**. Enforces the plugin contracts documented in docs/PLUGIN_AUTHORING.md.
+globs:
+  - "plugins/**"
+---
+
+# Plugin authoring rules
+
+These rules apply only when editing files under `plugins/**`. They encode the contracts described in [`docs/PLUGIN_AUTHORING.md`](../../docs/PLUGIN_AUTHORING.md) so AI suggestions don't drift from them.
+
+## Manifest
+
+- **`plugin.json` is required** and must validate against [`schema/plugin.schema.json`](../../schema/plugin.schema.json). Required fields: `id`, `name`. The `id` must match the parent directory name (the loader keys discovery by directory; drift breaks plugin lookup).
+- **Plugins declare capability intent** with `standards: ["capability-pipelines.v1"]` and redaction-safe `capabilities` / `ui` metadata. Treat these declarations as the plugin's primary contract with Slopsmith.
+- **License must come from the curated allowlist** if the plugin is intended for the curated list. See [`CONTRIBUTING.md`](../../CONTRIBUTING.md) "Plugin licensing".
+- **`type: "visualization"`** requires a `script` field exporting `window.slopsmithViz_<id>`. See [`docs/plugin-visualization-contracts.md`](../../docs/plugin-visualization-contracts.md).
+
+## Backend (`routes.py`)
+
+- **Use `context["log"]`, never `print()` or `traceback.print_exc()`.** The CI workflow blocks `print(` and `traceback.print_exc(` in `server.py` / `lib/`; plugin code should follow the same rule. The provided logger is a stdlib `logging.Logger` namespaced to `slopsmith.plugin.<id>` with correlation IDs, JSON mode, and rotation already wired. See [`docs/plugin-logging.md`](../../docs/plugin-logging.md).
+- **Multi-file plugins must use `context["load_sibling"]("<module>")`**, not bare `from <module> import X`. Two plugins shipping a same-named helper collide via `sys.modules`. See [`docs/plugin-sibling-imports.md`](../../docs/plugin-sibling-imports.md).
+- **`setup(app, context)` is the required entry.** Don't run side effects at import time.
+
+## Frontend (`screen.js`)
+
+- **Wrap in an IIFE** — `(function () { 'use strict'; ... })();`. Frontend scripts share global scope; leaking variables collides with other plugins.
+- **Prefer capability commands, events, and provider APIs** for app coordination. Don't add new private global wrappers or cross-plugin polling; if the needed domain is missing, call that out as a capability gap.
+
+## State and config
+
+- **`localStorage` keys must be prefixed with the plugin id** to avoid collisions.
+- **`settings.server_files` declares config-dir paths the plugin wants to include in the Settings export/import flow.** Relpaths only — no `..`, no abs paths, no backslashes. See [`docs/plugin-manifest.md`](../../docs/plugin-manifest.md).
+- **`diagnostics.server_files` / `diagnostics.callable`** declares what enters the Export Diagnostics bundle. Keep payloads under 100 KB and don't include secrets. See [`docs/plugin-diagnostics.md`](../../docs/plugin-diagnostics.md).
+
+## Visualization specifics
+
+When `plugin.json` declares `"type": "visualization"`:
+
+- **Factory must be `window.slopsmithViz_<id>`** where `<id>` matches `plugin.json`.
+- **Factory must return a fresh object on each call** — splitscreen creates N instances.
+- **The renderer owns its `getContext()` call.** Declare `contextType: '2d'` or `'webgl2'` on the returned object so the highway can swap the canvas element when needed (`getContext` is one-shot per canvas).
+- **`draw(bundle)` receives difficulty-filtered arrays** — never read from `_filteredNotes` or other internals.
+
+See [`docs/plugin-visualization-contracts.md`](../../docs/plugin-visualization-contracts.md) for the full lifecycle and the Overlay + Note-state-provider contracts.
+
+## Testing
+
+When changing plugin internals, add or update a test under `tests/` (Python) or `tests/js/` (Node) or `tests/browser/` (Playwright). See [`docs/testing-plugins.md`](../../docs/testing-plugins.md) for fixtures (`isolate_logging`, `reset_plugin_state`).
@@ -0,0 +1,16 @@
+{
+  "$schema": "https://json.schemastore.org/claude-code-settings.json",
+  "_comment": "Repo-default Claude Code settings for Slopsmith contributors. Hooks are intentionally empty by default — see commented example below.",
+
+  "hooks": {},
+
+  "_commented_example_hooks": {
+    "_comment": "Copy the block below into the empty `hooks` object above if you want plugin.json edits to be auto-validated against schema/plugin.schema.json, including capability metadata, on save. Per-user opt-in; not enabled by default because hooks run in every Claude Code session that loads this repo.",
+    "PostToolUse": [
+      {
+        "matcher": "Write|Edit",
+        "command": "if echo \"$CLAUDE_TOOL_INPUT_FILE_PATH\" | grep -qE '^plugins/[^/]+/plugin\\.json$'; then python -c \"import json,sys,jsonschema; s=json.load(open('schema/plugin.schema.json')); m=json.load(open('$CLAUDE_TOOL_INPUT_FILE_PATH')); jsonschema.validate(m,s); print('OK','$CLAUDE_TOOL_INPUT_FILE_PATH')\"; fi"
+      }
+    ]
+  }
+}
@@ -0,0 +1,85 @@
+---
+name: plugin-scaffold
+description: Scaffold a Slopsmith plugin skeleton with capability-pipelines metadata. USE WHEN the user asks to create a new plugin, scaffold a plugin, bootstrap a plugin, new visualization plugin, new overlay plugin, new settings-only plugin, plugin starter, plugin skeleton. Args needed - plugin slug (snake_case) and type (visualization / overlay / settings-only / routes-only). Generates plugins/<id>/ with plugin.json, capability-pipelines metadata, screen.js, and optional routes.py / settings.html / Playwright test stub matching the requested type.
+---
+
+# plugin-scaffold
+
+Generates a minimum-viable Slopsmith plugin skeleton matching a requested shape. The output validates against [`schema/plugin.schema.json`](../../../schema/plugin.schema.json).
+
+## When to invoke
+
+The user says one of:
+- "scaffold a new plugin called X"
+- "create a visualization plugin"
+- "new overlay plugin"
+- "plugin starter for settings"
+- "bootstrap a routes-only plugin"
+
+If the plugin slug or type is missing, ask once.
+
+## Inputs
+
+| Arg | Required | Values | Notes |
+|---|---|---|---|
+| `id` | yes | snake_case | Becomes plugin's `id` field and directory name |
+| `name` | optional | string | Defaults to title-case of `id` |
+| `type` | yes | `visualization` / `overlay` / `settings-only` / `routes-only` | Determines which files get scaffolded |
+
+## What to generate
+
+**Common to all types:**
+
+- `plugins/<id>/plugin.json` — schema-valid manifest. Set `id`, `name`, `version: "0.1.0"`, `license: "AGPL-3.0-only"`, and `standards: ["capability-pipelines.v1", "plugin-runtime-idempotent.v1"]` by default.
+
+**`type=visualization`** — adds:
+- `"type": "visualization"` and `"script": "screen.js"` to manifest
+- `"capabilities": { "visualization": { "roles": ["provider"], "operations": ["renderer.create", "renderer.destroy", "renderer.inspect"], "mode": "active", "compatibility": "none", "ownership": "multi-provider", "safety": "safe", "version": 1 } }`
+- `screen.js` exporting `window.slopsmithViz_<id> = function () { return { contextType: '2d', init(canvas, bundle) { this.ctx = canvas.getContext('2d'); }, draw(bundle) { /* TODO */ }, destroy() {} }; };` plus a static `matchesArrangement` example commented out
+- `tests/browser/<id>.spec.ts` — Playwright stub that loads the app and asserts the plugin's factory is registered
+
+**`type=overlay`** — adds:
+- `"script": "screen.js"` to manifest (no `type` declared — overlays don't use the picker)
+- `"capabilities": { "ui.player-overlays": { "roles": ["provider"], "mode": "active", "compatibility": "none", "ownership": "multi-provider", "safety": "safe", "version": 1 } }`
+- a matching `"ui"` contribution with a stable overlay id and redaction-safe label
+- `screen.js` scaffolding an own-canvas + own-rAF loop for the declared overlay contribution, and respecting renderer ownership if it uses highway geometry helpers
+- `tests/browser/<id>.spec.ts` — toggle on / off test
+
+**`type=settings-only`** — adds:
+- `"settings": { "html": "settings.html" }` to manifest
+- `"settings_schema"` with a schema version and an empty `packable_keys` list
+- a `"ui"` settings contribution with a stable id
+- `settings.html` — empty form skeleton with explanatory comments
+- `screen.js` reading/writing `localStorage` keys prefixed with `<id>_`
+
+**`type=routes-only`** — adds:
+- `"routes": "routes.py"` to manifest
+- a conservative `"capabilities"` declaration for the route's Slopsmith-facing workflow; if the domain is unclear, ask what capability domain the route owns, provides, requests, or observes before finalizing the scaffold
+- `routes.py` with `def setup(app, context):` that registers one example route and uses `context["log"].info("plugin ready")` (never `print()`)
+- `tests/test_<id>_routes.py` — FastAPI TestClient stub
+
+## After scaffolding
+
+Run validation locally:
+
+```bash
+python -c "import json,jsonschema; s=json.load(open('schema/plugin.schema.json')); jsonschema.validate(json.load(open('plugins/<id>/plugin.json')), s); print('OK')"
+```
+
+Then point the user at [`docs/PLUGIN_AUTHORING.md`](../../../docs/PLUGIN_AUTHORING.md) and the relevant contract doc for the type they chose.
+
+## Don'ts
+
+- Don't invent plugin-local manifest conventions. If the user wants something custom, either express it through existing `capability-pipelines.v1` metadata or ask whether it should become a real schema field.
+- Don't scaffold a `requirements.txt` without confirming the deps. The plugin loader installs them on first load; an accidental dep slows everyone's startup.
+- Don't pre-fill `localStorage` keys without a prefix. Collisions across plugins are real.
+- Don't generate hidden side effects at import time (`screen.js` top level or `routes.py` top level). Keep all wiring inside the IIFE / `setup()`.
+
+## Verification
+
+The scaffolded plugin should pass:
+
+```bash
+pytest tests/test_plugin_schema.py::test_in_tree_manifest_validates -v
+pytest tests/test_plugin_schema.py::test_in_tree_manifest_id_matches_directory -v
+```
@@ -0,0 +1,108 @@
+---
+name: plugin-validate
+description: Validate a Slopsmith plugin's plugin.json against the schema and run structural checks. USE WHEN the user asks to validate a plugin, check the manifest, plugin.json errors, lint plugin, verify plugin structure, plugin license check, or audit plugin contract. Runs JSON Schema validation, capability metadata checks, file-existence checks for declared script/routes/settings.html/tour paths, and license-allowlist check.
+---
+
+# plugin-validate
+
+Runs the same checks `.github/workflows/validate-plugins.yml` + `tests/test_plugin_schema.py` run in CI, but **locally and instantly** — useful for catching errors before push.
+
+## When to invoke
+
+The user says one of:
+- "validate plugins/<id>"
+- "check the manifest for X"
+- "lint this plugin"
+- "verify my plugin.json"
+- "plugin license check"
+
+Works on either a specific plugin (e.g. `plugins/highway_3d/`) or all in-tree plugins if none is specified.
+
+## What to run
+
+```bash
+# All in-tree plugins (default)
+python <<'PY'
+import json, glob, sys, jsonschema, pathlib
+schema = json.load(open('schema/plugin.schema.json'))
+jsonschema.Draft202012Validator.check_schema(schema)
+ok = True
+for path in sorted(glob.glob('plugins/*/plugin.json')):
+    plugin_dir = pathlib.Path(path).parent
+    plugin_id = plugin_dir.name
+    m = json.load(open(path))
+    plugin_ok = True  # per-iteration flag so we don't print OK after a later FAIL
+    # 1. Schema, including capability-pipelines.v1 metadata
+    try:
+        jsonschema.validate(m, schema)
+    except jsonschema.ValidationError as e:
+        print(f"FAIL {path}: {e.message} (at {list(e.absolute_path)})")
+        ok = False
+        continue
+    # 2. id == directory name
+    if m['id'] != plugin_id:
+        print(f"FAIL {path}: id={m['id']!r} but directory is {plugin_id!r}")
+        ok = False
+        plugin_ok = False
+    # 3. Declared files exist
+    for field in ('script', 'routes', 'tour'):
+        if field in m and not (plugin_dir / m[field]).exists():
+            print(f"FAIL {path}: {field}={m[field]!r} but file missing")
+            ok = False
+            plugin_ok = False
+    if 'settings' in m and 'html' in m['settings']:
+        h = m['settings']['html']
+        if not (plugin_dir / h).exists():
+            print(f"FAIL {path}: settings.html={h!r} but file missing")
+            ok = False
+            plugin_ok = False
+    for field in ('settings', 'diagnostics'):
+        if field in m and 'server_files' in m[field]:
+            for relpath in m[field]['server_files']:
+                # server_files paths live under context["config_dir"], NOT the
+                # plugin dir, so we don't existence-check them here. We only
+                # confirm the path *looks* safe (already enforced by schema).
+                if '..' in relpath or relpath.startswith('/') or '\\' in relpath:
+                    print(f"FAIL {path}: {field}.server_files contains unsafe path {relpath!r}")
+                    ok = False
+                    plugin_ok = False
+    if plugin_ok:
+        print(f"OK   {path}")
+sys.exit(0 if ok else 1)
+PY
+```
+
+## Targeted invocation
+
+If the user names a specific plugin, swap the glob for `plugins/<id>/plugin.json` and report on just that one.
+
+## License-allowlist check
+
+If the user specifically asks for a license check (or the plugin declares `license` in `plugin.json`), additionally run:
+
+```bash
+pytest tests/test_plugin_schema.py::test_schema_license_enum_subset_of_contributing_allowlist -v --noconftest
+```
+
+(or skip `--noconftest` if `structlog` is installed locally).
+
+## Output
+
+Use the format from the script: `OK <path>` per validated manifest, `FAIL <path>: <reason>` per failure. Add a one-line summary:
+
+```text
+Result: 3/3 plugins valid (OK app_tour_library, app_tour_settings, highway_3d)
+```
+
+or
+
+```text
+Result: 2/3 plugins valid; 1 FAIL (see above)
+```
+
+## Related
+
+- [`schema/plugin.schema.json`](../../../schema/plugin.schema.json)
+- [`tests/test_plugin_schema.py`](../../../tests/test_plugin_schema.py)
+- [`.github/workflows/validate-plugins.yml`](../../../.github/workflows/validate-plugins.yml)
+- [`docs/plugin-manifest.md`](../../../docs/plugin-manifest.md)
@@ -0,0 +1,85 @@
+name: Bug report
+description: Report something broken in Slopsmith core (server, frontend, library, player).
+title: "[bug] "
+labels: ["bug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for reporting! Before submitting:
+        - For **plugin** issues, please open the issue in the plugin's own repository instead — plugins under `plugins/` are separate projects.
+        - For sensitive logs, redact paths/credentials. The `docs/diagnostics-bundle-spec.md` describes the redaction surface used by Export Diagnostics.
+
+  - type: input
+    id: version
+    attributes:
+      label: Slopsmith version
+      description: "Contents of the `VERSION` file at the root, or what the navbar badge shows."
+      placeholder: "e.g. 0.2.8"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: deployment
+    attributes:
+      label: How are you running Slopsmith?
+      options:
+        - Docker Compose (docker-compose.yml)
+        - Bare Python (python main.py)
+        - Proxmox CT (build-proxmox-ct.sh)
+        - slopsmith-desktop bundle
+        - Other (describe below)
+    validations:
+      required: true
+
+  - type: input
+    id: os
+    attributes:
+      label: Host OS / browser
+      placeholder: "e.g. macOS 15.4 + Chrome 134; Linux + Firefox 142"
+    validations:
+      required: true
+
+  - type: input
+    id: plugins
+    attributes:
+      label: Plugins enabled
+      description: "List the plugins active when the bug happened. Most bugs reproduce only with certain plugins."
+      placeholder: "highway_3d, fretboard, note_detect"
+
+  - type: textarea
+    id: repro
+    attributes:
+      label: Reproduction steps
+      description: "Numbered steps. Include song format (legacy archive / sloppak / loose) and arrangement type if relevant."
+      placeholder: |
+        1. ...
+        2. ...
+        3. ...
+    validations:
+      required: true
+
+  - type: textarea
+    id: expected
+    attributes:
+      label: Expected vs. actual behaviour
+    validations:
+      required: true
+
+  - type: textarea
+    id: logs
+    attributes:
+      label: Logs / diagnostics
+      description: |
+        Either paste relevant log lines (set `LOG_LEVEL=DEBUG` or `LOG_FORMAT=json` if useful) **or** attach an Export Diagnostics bundle. See `docs/diagnostics-bundle-spec.md` for what's inside the bundle and what's redacted.
+      render: text
+
+  - type: checkboxes
+    id: terms
+    attributes:
+      label: Confirmations
+      options:
+        - label: I searched existing issues and didn't find a duplicate
+          required: true
+        - label: This is a core bug, not a plugin bug
+          required: true
@@ -1 +1,11 @@
-blank_issues_enabled: true
+blank_issues_enabled: false
+contact_links:
+  - name: Plugin issues
+    url: https://github.com/slopsmith/slopsmith#plugins
+    about: Plugins live in their own repositories. Open plugin bugs/features in the plugin's own repo.
+  - name: Documentation questions
+    url: https://github.com/slopsmith/slopsmith/tree/main/docs
+    about: Plugin contracts, sloppak spec, diagnostics, and note-detect tuning are documented under docs/. Try there first.
+  - name: Security disclosures
+    url: https://github.com/slopsmith/slopsmith/security
+    about: For security issues, please use GitHub's private security advisory flow rather than a public issue.
@@ -0,0 +1,57 @@
+name: Feature request
+description: Propose a feature, behaviour change, or new plugin contract.
+title: "[feature] "
+labels: ["enhancement"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        Thanks for the suggestion! For **plugin features**, open the issue in the plugin's own repository unless the change requires new core API.
+
+  - type: textarea
+    id: problem
+    attributes:
+      label: What problem does this solve?
+      description: "Lead with the user/contributor pain — the solution shape often falls out of a sharp problem statement."
+    validations:
+      required: true
+
+  - type: textarea
+    id: proposal
+    attributes:
+      label: Proposed solution
+      description: "What you'd like to see. UI mockups, code sketches, config examples all welcome."
+
+  - type: textarea
+    id: alternatives
+    attributes:
+      label: Alternatives considered
+
+  - type: dropdown
+    id: surface
+    attributes:
+      label: Which surface does this touch?
+      multiple: true
+      options:
+        - Server (FastAPI / lib/)
+        - Frontend (static/)
+        - Plugin contract (new field / event / API)
+        - Sloppak format
+        - WebSocket protocol
+        - Diagnostics
+        - Docs only
+        - Other (describe in proposal)
+
+  - type: textarea
+    id: plugin_impact
+    attributes:
+      label: Plugin author impact
+      description: "Does this require existing plugins to change? Add a new optional field? Break a contract? Be specific so the maintainer can size compatibility work."
+
+  - type: checkboxes
+    id: license
+    attributes:
+      label: License compatibility
+      options:
+        - label: If suggesting third-party code, it's AGPL-3.0-compatible (see CONTRIBUTING.md curated list)
+          required: true
@@ -0,0 +1,38 @@
+<!--
+Thanks for the PR! A few quick reminders before you hit submit:
+- DCO sign-off on every commit (git commit -s; --amend -s to fix)
+- Plugin work? Check docs/PLUGIN_AUTHORING.md and validate plugin.json
+  against schema/plugin.schema.json, including capability metadata
+- Touching the highway / player UI? Add or update a Playwright test
+  under tests/browser/
+-->
+
+## Summary
+
+<!-- 1–3 bullets describing what changes and why. Link related discussion. -->
+
+## Linked issue
+
+<!-- Closes #1234, or "n/a" if this is a chore/docs change -->
+
+## Test plan
+
+<!-- How did you verify? Tick what applies. -->
+
+- [ ] `pytest -q` passes locally
+- [ ] `npm run test:js` passes locally
+- [ ] `npm test` (Playwright) passes locally — *or* CI will run it
+- [ ] Verified in `docker compose up` (live-reload working directory)
+- [ ] Plugin manifest validates against `schema/plugin.schema.json` (including capability metadata)
+- [ ] Not applicable — explain below
+
+## Screenshots / recordings
+
+<!-- For UI changes, paste before/after. Drag-drop into the editor or use a GIF. -->
+
+## Checklist
+
+- [ ] DCO sign-off on every commit (`Signed-off-by:` trailer)
+- [ ] Conventional-commit subject (`feat(scope):`, `fix(scope):`, `docs:`, `chore:`)
+- [ ] `CHANGELOG.md` `[Unreleased]` section updated
+- [ ] Documentation updated if behaviour or contracts changed
@@ -0,0 +1,22 @@
+# GitHub Copilot instructions
+
+This file customizes GitHub Copilot Chat and Copilot inline suggestions for the Slopsmith repository.
+
+## Read first
+
+- [`AGENTS.md`](../AGENTS.md) — canonical project orientation (architecture, conventions, first-hour pitfalls, verification). This file is a thin pointer; the real content lives there.
+- [`docs/PLUGIN_AUTHORING.md`](../docs/PLUGIN_AUTHORING.md) — plugin work entry point
+
+## House rules
+
+- **License: AGPL-3.0-only.** Inbound contributions are AGPL-compatible. Do not suggest code copied verbatim from incompatible sources.
+- **DCO sign-off required** on every commit (`git commit -s`).
+- **No frontend frameworks.** Vanilla JS, Canvas, Tailwind classes. Do not suggest React/Vue/Svelte additions.
+- **Plugin backend logging.** Suggest `context["log"]`, never `print()`.
+- **Plugin Python imports.** For cross-file backend plugins, suggest `context["load_sibling"]("module_name")` instead of bare `from module_name import X`.
+- **Capability metadata.** For plugin integrations, suggest `standards: ["capability-pipelines.v1"]` and redaction-safe `capabilities` / `ui` metadata as the primary contract.
+- **DCO/license headers.** When creating a new file in the main repo, no license header is needed (the LICENSE file at root governs). Plugin authors should add an SPDX-License-Identifier comment to their plugin's source files; the `license` field in `plugin.json` must match the allowlist in [`CONTRIBUTING.md`](../CONTRIBUTING.md).
+
+## Validation
+
+When suggesting changes to a `plugin.json`, validate against [`schema/plugin.schema.json`](../schema/plugin.schema.json), including native `capability-pipelines.v1` metadata.
@@ -3,7 +3,7 @@ name: Sync VERSION from desktop release
 # Updates the VERSION file in this repo whenever slopsmith-desktop
 # publishes a new tagged release. slopsmith-desktop's build.yml
 # dispatches the `desktop-released` event at the end of a successful
-# tag build (see docs in CLAUDE.md). A `workflow_dispatch` trigger is
+# tag build (see Versioning section in AGENTS.md). A `workflow_dispatch` trigger is
 # kept for manual testing / recovery.
 #
 # Related issue: #81.
@@ -0,0 +1,82 @@
+name: Validate plugins
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'plugins/**/plugin.json'
+      - 'plugins/__init__.py'
+      - 'schema/plugin.schema.json'
+      - 'docs/plugin-manifest.schema.json'
+      - 'static/capabilities.js'
+      - 'CONTRIBUTING.md'
+      - 'requirements-test.txt'
+      - 'tests/test_plugin_schema.py'
+      - '.github/workflows/validate-plugins.yml'
+  pull_request:
+    branches: [main]
+    paths:
+      - 'plugins/**/plugin.json'
+      - 'plugins/__init__.py'
+      - 'schema/plugin.schema.json'
+      - 'docs/plugin-manifest.schema.json'
+      - 'static/capabilities.js'
+      - 'CONTRIBUTING.md'
+      - 'requirements-test.txt'
+      - 'tests/test_plugin_schema.py'
+      - '.github/workflows/validate-plugins.yml'
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+          cache: 'pip'
+
+      - name: Install jsonschema
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements-test.txt
+
+      - name: Validate every in-tree plugin.json against capability schema
+        run: |
+          python - <<'PY'
+          import glob, json, sys
+          import jsonschema
+
+          schema_path = "schema/plugin.schema.json"
+          with open(schema_path) as f:
+              schema = json.load(f)
+
+          # Validate the schema itself is a well-formed JSON Schema.
+          jsonschema.Draft202012Validator.check_schema(schema)
+
+          manifests = sorted(glob.glob("plugins/*/plugin.json"))
+          if not manifests:
+              print("No plugin manifests found under plugins/*/plugin.json")
+              sys.exit(0)
+
+          failures = []
+          for path in manifests:
+              with open(path) as f:
+                  manifest = json.load(f)
+              try:
+                  jsonschema.validate(manifest, schema)
+                  print(f"OK   {path}")
+              except jsonschema.ValidationError as e:
+                  failures.append((path, e))
+                  print(f"FAIL {path}: {e.message} (at {list(e.absolute_path)})")
+          if failures:
+              sys.exit(1)
+          PY
+
+      - name: Run schema and capability contract tests
+        # --noconftest skips tests/conftest.py, which imports structlog
+        # (not in requirements-test.txt). The schema tests don't use
+        # shared fixtures, so this is safe and avoids dragging the full
+        # runtime requirements into a 2 KB schema-validation job.
+        run: pytest tests/test_plugin_schema.py -v --noconftest
@@ -1,13 +1,28 @@
+<!--
+Sync Impact Report
+Version change: 1.1.0 -> 1.2.0
+Modified principles:
+- III. Plugins Are the Extension Point — Isolated by `load_sibling` -> III. Plugins Are the Extension Point — Capability-Declared and Isolated
+Added sections: None
+Removed sections: None
+Templates requiring updates:
+- [updated] .specify/templates/plan-template.md — Constitution Check now names Slopsmith's concrete gates, including plugin capability declarations.
+- [reviewed] .specify/templates/spec-template.md — no structural update required; requirements remain feature-focused.
+- [reviewed] .specify/templates/tasks-template.md — no structural update required; the plan gate drives capability-related tasks.
+- [reviewed] .specify/templates/checklist-template.md — no structural update required.
+Follow-up TODOs: None
+-->
+
 # Slopsmith Constitution

 > Slopsmith is a self-hosted, single-user web app for browsing, playing, and
-> practicing interactive music notation, built around its own open `.sloppak`
+practicing interactive music notation, built around its own open `.sloppak`
 > chart format (charts imported from Guitar Pro / MusicXML or authored in the
 > built-in editor). This constitution captures the non-negotiable principles
 > that govern its core (`server.py`, `lib/`, `static/`) and that all in-tree
 > plugins (`plugins/<name>/`) inherit by default. It is a *retrospective*
 > document — the codebase came first, the principles below were distilled from
-> `CLAUDE.md`, `README.md`, and the shape of the existing implementation.
+> `AGENTS.md`, `README.md`, and the shape of the existing implementation.

 ## Core Principles

@@ -69,28 +84,45 @@ features extend `app.js` and the existing globals (`window.playSong`,
  layout invariants (`#player` flex-column, `#highway` flex:1,
  `#player-controls` at the bottom) MUST be preserved.

-### III. Plugins Are the Extension Point — Isolated by `load_sibling`
+### III. Plugins Are the Extension Point — Capability-Declared and Isolated

 Functionality that is not part of the irreducible "browse + play charts"
 loop ships as a plugin under `plugins/<name>/`, not as core code. Each
 plugin is its own directory (typically a separate git repo), discovered
 at startup via `plugin.json`, and free to add nav links, screens,
-settings panels, and `/api/plugins/<id>/...` routes. Plugins MUST
-isolate their backend Python imports via `context["load_sibling"]` so
-two plugins shipping a generic `extractor.py` / `util.py` / `client.py`
-do not collide in `sys.modules`.
+settings panels, and `/api/plugins/<id>/...` routes. Slopsmith-facing
+plugin behavior is capability-declared by default: manifests describe
+the domains a plugin owns, provides, requests, observes, validates, or
+contributes to before any runtime script hydrates. Runtime handlers,
+legacy wrappers, and private globals are implementation details or
+compatibility bridges, never the primary integration contract. Plugins
+MUST isolate their backend Python imports via `context["load_sibling"]`
+so two plugins shipping a generic `extractor.py` / `util.py` /
+`client.py` do not collide in `sys.modules`.

 **Non-negotiable rules**

 - Generic features (practice journal, setlist, metronome, tone player,
  tab view, MIDI control, stem mixing, editors, etc.) belong in a plugin
  repo, not in `lib/` or `server.py`.
+- Plugins with Slopsmith-facing behavior MUST declare
+  `standards: ["capability-pipelines.v1"]` plus redaction-safe
+  `capabilities`, `ui`, or `ui_contributions` metadata for the behavior
+  they expose. Metadata-only or transitional manifests that omit
+  capability participation MUST document why no current domain applies.
+- Runtime participants, event listeners, wrapper hooks, timers, DOM
+  roots, diagnostics contributors, and media nodes MUST be idempotent
+  across repeated script hydration. If a wrapper or private global is
+  still required, it MUST be documented as a compatibility bridge or a
+  missing capability-domain gap.
 - Plugin backend modules MUST use `context["load_sibling"]("name")` for
  sibling imports. Bare `import sibling` works during transition but
  triggers a startup warning when a name collides.
 - Plugins MUST register routes under `/api/plugins/<plugin_id>/...`,
-  use `window.slopsmith.emit/on` for cross-plugin communication, and
-  prefix their `localStorage` keys with their plugin id.
+  use capability commands/events when an active domain exists, and
+  prefix their `localStorage` keys with their plugin id. General
+  `window.slopsmith.emit/on` events remain acceptable for host events or
+  domains that have not yet been promoted.
 - Plugins inherit this constitution and may layer additional rules in
  their own `CLAUDE.md`, but MUST NOT relax core principles (e.g. a
  plugin cannot require a frontend framework in core).
@@ -207,11 +239,12 @@ no `..`, no absolute paths).
  `flex:1`; `#player-controls` sits at the bottom. Hiding the highway
  collapses the layout — use `margin-top: auto` on controls if you
  need to hide it.
- **Plugin load order**: alphabetical by directory name. The
-  `playSong` wrapper chain runs outermost-first (last-loaded wrapper
-  runs first). Plugins MUST tolerate dependent globals being absent
-  at load time and check at runtime
-  (`typeof window.X === 'function'`).
+- **Plugin load order**: alphabetical by directory name. Scripts MUST
+  tolerate dependent globals being absent at load time and check at
+  runtime (`typeof window.X === 'function'`). Load order and the
+  `playSong` wrapper chain are implementation details, not integration
+  contracts; plugins declare roles, ownership, compatibility, and UI
+  contributions through capability metadata.

 ## Development Workflow

@@ -225,8 +258,9 @@ no `..`, no absolute paths).
  After pushing a fix, the CodeRabbit loop
  (`feedback_coderabbit_review.md`) runs to silence.
 - **Testing**: `pytest` for backend (`requirements-test.txt`),
-  Playwright for browser interactions (`tests/browser/`), CI runs both
-  on every push/PR to `main`.
+  Playwright for browser interactions (`tests/browser/`), and plugin
+  manifest schema validation for capability metadata. CI runs these on
+  every relevant push/PR to `main`.
 - **CHANGELOG**: every PR updates `[Unreleased]`. Releases rename
  `[Unreleased]` to `[X.Y.Z] - YYYY-MM-DD` (the VERSION bump itself is
  automated).
@@ -246,12 +280,13 @@ no `..`, no absolute paths).
  explicit constitutional amendment in this file.
 - Amendments require: (a) a PR that updates this file alongside the
  code change, (b) an entry in `CHANGELOG.md` under "Migration notes"
-  if user-visible, and (c) a corresponding update to `CLAUDE.md` so
-  AI agents and humans see the same source of truth.
+  if user-visible, and (c) a corresponding update to `AGENTS.md` and any
+  agent-specific imports or instructions so AI agents and humans see the
+  same source of truth.
 - The principles are listed in priority order. When two principles
  conflict (e.g. "vanilla frontend" vs. a plugin that wants to ship
  React), the lower-numbered principle wins by default; the
  higher-numbered principle's escape hatch is to live in a plugin
  with its own bundled assets.

-**Version**: 1.1.0 | **Ratified**: 2026-05-09 | **Last Amended**: 2026-06-01
+**Version**: 1.2.0 | **Ratified**: 2026-05-09 | **Last Amended**: 2026-06-03
@@ -31,7 +31,29 @@

 *GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.*

-[Gates determined based on constitution file]
+Answer each gate with PASS / FAIL / N/A and a short justification:
+
+- **Self-hosted Docker path**: Does the feature keep `DLC_DIR` and
+  `CONFIG_DIR` as the only required runtime inputs, with any new
+  dependency installable in the existing Docker image?
+- **Vanilla/source-served frontend**: Does core remain plain JS and
+  committed CSS, with no framework, runtime CDN/JIT, bundler, or
+  serve-path build step? If plugin CSS is needed, does it ship through
+  `styles`?
+- **Plugin and capability boundary**: If the feature is outside browse +
+  play custom DLC, is it plugin-shaped? Does every Slopsmith-facing plugin
+  behavior declare `capability-pipelines.v1` metadata (`capabilities`,
+  `ui`, or `ui_contributions`) and use `load_sibling` for backend
+  siblings?
+- **Song format compatibility**: Are legacy archive scanning, sloppak manifests,
+  arrangement IDs, and highway WebSocket messages kept backward-
+  compatible, or is a migration note planned?
+- **Pure/testable core**: Are new `lib/` helpers flat-importable,
+  side-effect-light, and covered where practical?
+- **Observability and diagnostics**: Does backend output use logging,
+  and do diagnostics remain redacted and versioned?
+- **Settings/versioning**: Are settings imports/export paths safe,
+  additive/idempotent, and compatible with the `VERSION` workflow?

 ## Project Structure

@@ -0,0 +1,179 @@
+# AGENTS.md
+
+Project orientation for AI coding assistants (Cursor, GitHub Copilot, OpenAI Codex, Aider, Claude Code, Cline, Continue, Cody, Devin, …) and human contributors.
+
+Slopsmith is a self-hosted web app for browsing, playing, and practicing interactive music notation, built around its own open `.sloppak` chart format. Charts come from importing Guitar Pro (GP5/GP8) or MusicXML, or from authoring in the built-in editor. It runs as a Docker container with a FastAPI backend (`server.py`), vanilla JavaScript frontend (`static/`), shared Python libraries (`lib/`), and an extensive plugin system (`plugins/`). No frontend frameworks — plain JS, HTML, Tailwind CSS. AGPL-3.0-only.
+
+This file is the canonical orientation. Tool-specific automation (Claude skills/subagents/rules, Copilot instructions, etc.) lives in [`.claude/`](.claude/) and [`.github/copilot-instructions.md`](.github/copilot-instructions.md); both point back here. For plugin work, start at [`docs/PLUGIN_AUTHORING.md`](docs/PLUGIN_AUTHORING.md).
+
+## Architecture quick reference
+
+```text
+server.py              FastAPI app — library API, WebSocket highway, plugin loading
+main.py                Programmatic uvicorn entrypoint — installs structlog before boot
+logging_setup.py       Structured logging + correlation IDs (LOG_LEVEL/LOG_FORMAT/LOG_FILE)
+static/
+  app.js               Main frontend — screens, library views, player, plugin loader
+  highway.js           Canvas note highway renderer (createHighway factory)
+  diagnostics.js       window.slopsmith.diagnostics namespace (loaded first in <head>)
+  index.html           Single-page app shell
+lib/
+  song.py              Core data models (Note, Chord, Arrangement, Song)
+  sloppak.py           Sloppak format support
+  sloppak_convert.py   Import conversion + Demucs stem split
+  loosefolder.py       Loose-folder XML chart support
+  audio.py             WEM/OGG/MP3 audio handling
+  retune.py            Pitch-shifting logic
+  tunings.py           Tuning name/offset utilities
+  gp2rs.py             Guitar Pro to arrangement XML conversion
+  gp2midi.py           Guitar Pro to MIDI
+plugins/
+  __init__.py          Plugin discovery, loading, requirements install, load_sibling
+  <plugin>/            Each plugin is its own directory (often a git submodule)
+schema/
+  plugin.schema.json   JSON Schema for plugin.json (validated in CI)
+docs/                  Plugin contracts + format specs (see Plugin authoring below)
+tests/                 pytest + tests/js/ (node --test) + tests/browser/ (Playwright)
+specs/                 Active spec-kit features (specs/001-slopsmith-platform/...)
+```
+
+## Running the app
+
+Canonical dev path is Docker Compose — `docker-compose.yml` live-mounts `static/`, `server.py`, `lib/`, `plugins/`, and `VERSION` into the container, so frontend edits are visible on refresh and backend edits trigger uvicorn auto-reload.
+
+```bash
+docker compose up                                     # build + run on :8000
+DLC_PATH=/path/to/dlc docker compose up               # override default Steam DLC path
+```
+
+For host-side runs (tests, scripts, no Docker), the programmatic entry point is `main.py`:
+
+```bash
+python main.py                                        # HOST=0.0.0.0 PORT=8000 default
+HOST=127.0.0.1 PORT=8001 python main.py
+```
+
+`main.py` installs the structlog pipeline via `logging_setup.configure_logging()` **before** uvicorn boots and passes `log_config=None` so uvicorn's `dictConfig` never overwrites it. Do not invoke `uvicorn server:app` directly during development — early lifecycle log lines will bypass the structured pipeline and correlation IDs.
+
+**Logging env vars** (read by `logging_setup`):
+- `LOG_LEVEL` — `DEBUG | INFO | WARNING | ERROR` (default `INFO`)
+- `LOG_FORMAT` — `json | text` (default `text` — coloured console)
+- `LOG_FILE` — optional path for a persistent log file (e.g. `/config/slopsmith.log`)
+
+Plugin backend code receives a pre-configured `context["log"]` logger namespaced to `slopsmith.plugin.<id>` — never use `print()`. See [`docs/plugin-logging.md`](docs/plugin-logging.md).
+
+## Testing
+
+```bash
+pytest                              # All Python tests
+pytest tests/test_plugins.py -v     # Specific file
+pytest -k "load_sibling" -v         # Pattern match
+
+npm run test:js                     # Node-native JS plugin-API contract tests (tests/js/)
+npm run install:playwright          # One-time: install Chromium for Playwright
+npm test                            # Playwright browser tests (tests/browser/)
+```
+
+Pytest config in `pyproject.toml` sets `pythonpath = [".", "lib"]` and `testpaths = ["tests"]`. CI runs `pytest` on every push/PR to `main` (Python 3.12). See [`docs/testing-plugins.md`](docs/testing-plugins.md) for fixtures (`isolate_logging`, `reset_plugin_state`) and Playwright patterns.
+
+## Git workflow
+
+- **Never push directly to `main`** — always create a feature branch and open a PR.
+- **DCO sign-off is mandatory.** `git commit -s` appends `Signed-off-by:`. Forgot? `git commit --amend -s`. See [`CONTRIBUTING.md`](CONTRIBUTING.md).
+- **Upstream remote** — set `upstream` to the canonical Slopsmith repository; `origin` is your fork.
+- **Plugins are gitlinks** — each plugin in `plugins/` is typically its own git repo (submodule or clone). Branch switches on the main repo can clobber plugin directories. Use `git update-index --assume-unchanged` for plugin dirs if needed.
+- **Commit style** — short imperative subject line, blank line, then body explaining *why*. Conventional-commit prefixes (`feat(scope):`, `fix(scope):`, `chore:`, `docs:`) are conventional in the log but not enforced.
+
+## Versioning
+
+- **`VERSION`** (repo root) — single source of truth; plain semver string. Bind-mounted into the container and copied by the Dockerfile so it's always available at `/app/VERSION`.
+- **`GET /api/version`** — returns `{"version", "source_url", "license_url"}`. `source_url` is overridable via `APP_SOURCE_URL` (default `https://github.com/byrongamatos/slopsmith`); `license_url` falls back to `source_url + "/blob/main/LICENSE"` and is overridable via `APP_LICENSE_URL`. Both must be `http(s)`; non-http(s) values are rejected.
+- **Auto-sync** — `.github/workflows/sync-version.yml` rewrites `VERSION` via a `repository_dispatch` (`desktop-released`) from `slopsmith-desktop`'s release job. As an explicit automation-only exception to "Never push directly to main", the sync job commits straight to `main` as `github-actions[bot]`. Humans still go through PRs.
+- **`CHANGELOG.md`** — [Keep a Changelog](https://keepachangelog.com/) format. Update `[Unreleased]` on each PR; release renames it.
+
+## Song formats
+
+Slopsmith supports two:
+
+- **Legacy archive** (encrypted, read-only) — fast metadata scan via `lib/sloppak.py`; full unpack for playback. Audio via `vgmstream-cli` + `ffmpeg`.
+- **Sloppak** (open format) — hand-editable, two interchangeable forms: `.sloppak` zip or `.sloppak/` directory. Preferred for new features. Full spec: [`docs/sloppak-spec.md`](docs/sloppak-spec.md). Key code: `lib/sloppak.py`, `lib/sloppak_convert.py`, `lib/song.py`.
+
+## Frontend conventions
+
+- **No frameworks** — vanilla JS, fetch API, DOM manipulation
+- **Plugin integration** — prefer documented capability domains, provider APIs, and redaction-safe UI contributions over private globals
+- **Storage** — `localStorage` for all user preferences, prefixed with plugin id
+- **Styling** — Tailwind utility classes; dark theme (`bg-dark-600`, `text-gray-300`, accent `#4080e0`, gold `#e8c040`)
+- **Naming** — camelCase for JS, kebab-case for CSS, snake_case for plugin IDs
+- **Player layout** — `#player` is `display:flex; flex-direction:column; position:fixed; inset:0`. `#highway` is `flex:1`. Hiding the highway collapses the layout — use `margin-top: auto` on controls if you must hide it.
+
+## Backend conventions
+
+- **Framework** — FastAPI + uvicorn (boot via `main.py`)
+- **Imports** — flat imports from `lib/` (no `__init__.py`): `from song import Song`
+- **Database** — SQLite via `MetadataDB` class with `threading.Lock`
+- **WebSocket** — JSON frames, try/except `WebSocketDisconnect`. Protocol: [`docs/websocket-protocol.md`](docs/websocket-protocol.md)
+- **Error handling** — graceful fallbacks (audio conversion errors don't crash the song; missing art returns a placeholder)
+- **Type hints** — used sparingly (`Path | None`, `dict`, `list`)
+- **Docstrings** — minimal; code is self-documenting
+
+## Plugin authoring — see [`docs/PLUGIN_AUTHORING.md`](docs/PLUGIN_AUTHORING.md)
+
+Plugins are the primary extension point. Each lives in `plugins/<name>/` with a `plugin.json` manifest that declares its `capability-pipelines.v1` participation. Curated plugins must be AGPL-3.0 or AGPL-compatible — see [`CONTRIBUTING.md`](CONTRIBUTING.md) for the allowlist. Manifest is validated in CI against [`schema/plugin.schema.json`](schema/plugin.schema.json), including capability metadata.
+
+Topic | Doc
+--- | ---
+Manifest reference (`plugin.json` fields) | [`docs/plugin-manifest.md`](docs/plugin-manifest.md)
+Capability declarations (`standards`, `capabilities`, `ui`) | [`docs/plugin-manifest.md#capabilities`](docs/plugin-manifest.md#capabilities)
+Visualization contracts | [`docs/plugin-visualization-contracts.md`](docs/plugin-visualization-contracts.md)
+Plugin styles (`styles: "assets/plugin.css"`) | [`docs/plugin-styles.md`](docs/plugin-styles.md)
+Backend `context["log"]` logging | [`docs/plugin-logging.md`](docs/plugin-logging.md)
+Diagnostics opt-in (export bundle) | [`docs/plugin-diagnostics.md`](docs/plugin-diagnostics.md)
+Multi-file backends (`load_sibling`) | [`docs/plugin-sibling-imports.md`](docs/plugin-sibling-imports.md)
+WebSocket highway protocol | [`docs/websocket-protocol.md`](docs/websocket-protocol.md)
+Testing plugins (pytest + Playwright) | [`docs/testing-plugins.md`](docs/testing-plugins.md)
+Diagnostics bundle layout | [`docs/diagnostics-bundle-spec.md`](docs/diagnostics-bundle-spec.md)
+Sloppak format spec | [`docs/sloppak-spec.md`](docs/sloppak-spec.md)
+Tuning the note_detect plugin | [`docs/note-detect-tuning.md`](docs/note-detect-tuning.md)
+
+## First-hour pitfalls (read these before your first PR)
+
+1. **`load_sibling` for cross-file backend plugins.** Bare `from extractor import X` in `routes.py` collides across plugins because Python caches by module name in `sys.modules`. Use `context["load_sibling"]("extractor")` — gets a per-plugin namespaced module. Full explanation: [`docs/plugin-sibling-imports.md`](docs/plugin-sibling-imports.md).
+
+2. **Capability declarations are the integration map.** Plugin behavior should be visible in `standards`, `capabilities`, and `ui` metadata before runtime code hydrates. If the domain you need is missing, document it as a capability gap instead of adding another private global contract.
+
+3. **Highway flex layout.** `#highway` has `flex:1` in the player. Hiding it with `display:none` removes the flex child and `#player-controls` floats to the top. If you must hide the highway, add `margin-top: auto` to the controls div.
+
+4. **Plugin gitlinks bite on branch switches.** Plugins are separate git repos cloned into `plugins/`. `git checkout` / `git clean` on the main repo can delete or clobber them. Use `git update-index --assume-unchanged plugins/<id>` if needed.
+
+5. **DCO sign-off is mandatory.** Every commit needs `Signed-off-by:`. Add via `git commit -s` (or `git commit --amend -s` if you forgot). PRs without DCO won't merge.
+
+## Verification (run before claiming done)
+
+```bash
+pytest -q                         # backend tests
+npm run test:js                   # JS plugin-API contract tests
+npm test                          # Playwright browser tests (slow; defers to CI)
+```
+
+If you touched `plugins/*/plugin.json` or `schema/`:
+
+```bash
+python -c "import json,glob,jsonschema; s=json.load(open('schema/plugin.schema.json')); [jsonschema.validate(json.load(open(p)), s) for p in sorted(glob.glob('plugins/*/plugin.json'))]"
+```
+
+## House rules
+
+- **AGPL-3.0-only.** Inbound contributions are inbound under the same terms. Don't paste from incompatible sources.
+- **DCO sign-off mandatory** on every commit (`git commit -s`).
+- **No frontend frameworks.** Vanilla JS, fetch API, Tailwind classes. Don't add React/Vue/Svelte.
+- **Backend logging.** Plugin `routes.py` must use `context["log"]`, never `print()`. See [`docs/plugin-logging.md`](docs/plugin-logging.md).
+- **Plugin Python imports.** Multi-file backends use `context["load_sibling"]("<module>")`, not bare `from <module> import`. See [`docs/plugin-sibling-imports.md`](docs/plugin-sibling-imports.md).
+- **Capability metadata.** Plugin integrations declare `standards: ["capability-pipelines.v1"]` plus redaction-safe `capabilities`/`ui` metadata as the primary integration contract.
+- **Spec-kit owns `.specify/` and `specs/`.** Don't modify those without explicit instruction; the `/speckit-*` skills own that surface.
+
+## Tool-specific surfaces (optional reading)
+
+- [`CLAUDE.md`](CLAUDE.md) — points back here. Exists for Claude Code's auto-loading convention. Claude-specific *automation* lives in [`.claude/`](.claude/) (skills, subagents, rules, settings).
+- [`.github/copilot-instructions.md`](.github/copilot-instructions.md) — points back here. Exists for GitHub Copilot's native instructions format.
+- No `.cursorrules` — Cursor reads `AGENTS.md` natively. Cursor-specific rules, if ever needed, would go under `.cursor/rules/`.
@@ -51,6 +51,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **`highway.getPhrases()` and `highway.getMastery()` public plugin API** — exposes phrase timing windows (`[{ index, start_time, end_time, max_difficulty }]`) and the current mastery slider value (`0..1`) as documented, stable plugin API. Both values were already in memory and reachable via internal names; this surfaces them with intent so plugins can implement section-aware logic (e.g. tracking accuracy per phrase, suppressing difficulty changes during a hard solo) without reaching into undocumented internals. Returns `null` when the song has no phrase data (GP imports, single-difficulty charts). Pair with the existing `hasPhraseData()` to gate phrase-aware code paths.
 - **Tailwind freshness guard + wider plugin scan.** A new `tailwind-fresh` CI job (`.github/workflows/tests.yml`) rebuilds `static/tailwind.min.css` with the pinned `tailwindcss@3.4.19` and hard-fails on any diff, so the committed prebuilt stylesheet can no longer silently lag source (after PR #411 removed the runtime Play CDN, a stale file shipped unstyled elements with no guard). The `tailwind.config.js` plugin content glob is widened to `./plugins/**/*.{js,html}`, which also scans non-`screen.js` plugin JS (e.g. `plugins/app_tour_*/script.js`) that was previously invisible to the build. Regenerating under the wider glob is a no-op for runtime behaviour — it only adds classes that were already used in source. Groundwork for the plugin `styles` capability (constitution 1.1.0, Principle II): runtime-installed plugins ship their own compiled CSS rather than relying on core's build-time scan.
 - **Plugin capability pipelines** — adds the first versioned capability coordination layer for plugin authors and support tooling. `/api/plugins` now exposes validated capability declarations, validation warnings, unsupported-version metadata, UI/runtime domain declarations, and compatibility shim summaries for legacy `nav` / `screen` / `settings` / `routes` / visualization surfaces. The browser runtime now tracks manifest participants separately from live handlers, explicit dispatch outcomes (`no-owner`, `no-handler`, `unsupported-command`, `incompatible-version`), claim lifecycle cleanup, manual override precedence, deterministic ownership conflicts, multi-provider ordering, shim hit counts, and a redaction-safe diagnostics snapshot capped at 64 KB. A bundled Capability Inspector plugin shows the live graph, and new docs cover the manifest schema, recipes, safety matrix, lifecycle cleanup, and diagnostics contract.
+- **Constitution 1.2.0 codifies capability-first plugins.** Principle III now makes `capability-pipelines.v1` manifest declarations the default Slopsmith-facing plugin contract, treats wrappers/private globals as compatibility bridges or capability gaps, and adds a concrete spec-kit Constitution Check gate for plugin capability metadata.
 - **Audio graph/session capability slice** — promotes `audio-mix`, `audio-input`, `audio-monitoring`, and coordinated `stems` diagnostics into the capability runtime. The new audio session host records song route/fader state, redaction-safe input sources, monitoring lifecycle outcomes, stem automation claims/overrides/orphans, and compatibility bridge hits for legacy faders, song volume, Stems master volume, 3D Highway analyser taps, audio startup barriers, and input source handoffs. `core.audio.session` coordinates `stems` without replacing the Stems plugin as the owner of actual stem playback/state.
 - **Audio-mix control plane** — makes `audio-mix` the player mixer source of truth. Core now exposes `list-faders`, `get-fader-value`, `set-fader-value`, `inspect-route`, and `inspect-analyser` through the capability runtime, routes native and compatibility-backed fader provider operations with a 2-second timeout, reports committed values back to the mixer UI, suppresses matching legacy faders when a native participant owns the same logical control, and expands audio-session diagnostics/Capability Inspector rendering for fader availability, source modes, bridge hits, route/analyser summaries, and timeout failures.
 - **Audio-input control plane** — makes `audio-input` the redaction-safe source of truth for instrument input discovery and lifecycle. Core now exposes `list-sources`, `select-source`, `open-source`, and `close-source` through the capability runtime, persists selected logical sources, keeps inspect/list/select prompt-free, routes provider `source.open`/`source.close` operations with bounded outcomes, shares compatible open sessions across requesters, suppresses compatibility-backed duplicate sources when a native provider owns the same logical key, and expands audio-session diagnostics/Capability Inspector rendering for selected input, open sessions, bridge hits, storage status, and permission/device failures without exposing raw device labels or live audio handles.
@@ -1,633 +1,22 @@
-# Slopsmith — AI Agent Guide
+# CLAUDE.md

-Slopsmith is a self-hosted web app for browsing, playing, and practicing interactive music notation, built around its own open `.sloppak` chart format. Charts come from importing Guitar Pro (GP5/GP8) or MusicXML, or from authoring in the built-in editor. It runs as a Docker container with a FastAPI backend (`server.py`), vanilla JavaScript frontend (`static/`), shared Python libraries (`lib/`), and an extensive plugin system (`plugins/`). There are no frontend frameworks — everything is plain JS, HTML, and Tailwind CSS.
+Claude Code memory file. This repo's canonical project orientation lives in [`AGENTS.md`](AGENTS.md) - the cross-tool standard read by Cursor, Copilot, Codex, Aider, Cline, and others. The line below uses Claude Code's `@`-import to inline AGENTS.md into this memory file, so there's a single source of truth and no drift between two near-duplicate files.

-## Architecture Quick Reference
+@AGENTS.md

-```
-server.py              FastAPI app — library API, WebSocket highway, plugin loading
-static/
-  app.js               Main frontend — screens, library views, player, plugin loader
-  highway.js           Canvas note highway renderer (createHighway factory)
-  index.html           Single-page app shell
-  style.css            Custom CSS loaded alongside Tailwind
-lib/
-  song.py              Core data models (Note, Chord, Arrangement, Song)
-  sloppak.py           Sloppak format support
-  loosefolder.py       Loose-folder XML chart support
-  audio.py             OGG/MP3 audio handling
-  retune.py            Pitch-shifting logic
-  tunings.py           Tuning name/offset utilities
-  gp2rs.py             Guitar Pro to arrangement XML conversion
-  gp2midi.py           Guitar Pro to MIDI
-plugins/
-  __init__.py           Plugin discovery, loading, requirements install
-  <plugin_name>/        Each plugin is its own directory (often a git submodule)
-tests/
-  test_*.py             pytest test suite
-```
+## Claude-specific surfaces

-## Plugin System
+The rest of this file is content that *only* makes sense for Claude Code (other AI tools have their own incompatible automation mechanisms). Skills, subagent, rule, and settings live under [`.claude/`](.claude/):

-Plugins are the primary extension point. Each plugin lives in `plugins/<name>/` with a `plugin.json` manifest. Plugins are typically their own git repositories — see [CONTRIBUTING.md](CONTRIBUTING.md) for the licensing policy (curated plugins should be AGPL-3.0 or AGPL-compatible: MIT, BSD, Apache-2.0).
+- [`.claude/skills/plugin-scaffold/`](.claude/skills/plugin-scaffold/SKILL.md) - generates a plugin skeleton with capability-pipelines metadata.
+- [`.claude/skills/plugin-validate/`](.claude/skills/plugin-validate/SKILL.md) - validates `plugin.json` against `schema/plugin.schema.json` locally before push.
+- [`.claude/skills/speckit-*/`](.claude/skills/) - spec-kit skills (auto-generated from `.specify/`; don't edit manually).
+- [`.claude/rules/plugin-author.md`](.claude/rules/plugin-author.md) - glob-scoped to `plugins/**`; encodes the contracts from `docs/PLUGIN_AUTHORING.md` so suggestions don't drift from them.
+- [`.claude/agents/slopsmith-reviewer.md`](.claude/agents/slopsmith-reviewer.md) - plugin-aware code-review subagent. Invoke with `@slopsmith-reviewer`.
+- [`.claude/settings.json`](.claude/settings.json) - repo defaults (no hooks enabled by default; commented opt-in example for `plugin.json` validation on save).

-```json
-{
-  "id": "my_plugin",
-  "name": "My Plugin",
-  "version": "1.0.0",
-  "private": false,
-  "type": "visualization",
-  "nav": { "label": "My Plugin", "screen": "plugin-my_plugin" },
-  "screen": "screen.html",
-  "script": "screen.js",
-  "styles": "assets/plugin.css",
-  "routes": "routes.py",
-  "settings": {
-    "html": "settings.html",
-    "server_files": ["my_plugin.db", "my_plugin_models/"]
-  },
-  "diagnostics": {
-    "server_files": ["my_plugin.diag.json"],
-    "callable": "diagnostics:collect"
-  }
-}
-```
+See [`.claude/README.md`](.claude/README.md) for conventions when adding more.

-All fields except `id` and `name` are optional. Plugins can have any combination of frontend (screen/script), backend (routes), and settings.
+## Why this file is short

-`version` and `private` are advisory metadata — the plugin loader does not currently consume them, but plugins commonly include them for publishing/tooling purposes.
-
-`description`, `category`, and `icon` are **optional, additive v3 Pedalboard metadata** (surfaced in `/api/plugins`, consumed by the v3 Plugins page `static/v3/plugins-page.js`). `description` is a short one-sentence summary shown under the pedal name. `category` (`audio | creation | practice | game | tools`, free-form; unknown/absent → curated default → `"other"`) picks which pedalboard the plugin sits on. `icon` is an assets-relative thumbnail path (e.g. `"assets/thumb.png"`, ~square ~256×256, same containment rule as `styles`, served via `/api/plugins/<id>/assets/...`); if omitted the loader auto-detects `assets/thumb.png`, and plugins with no thumbnail get a default pedal graphic. All three are backward-compatible — omit them and the plugin still loads. See [docs/plugin-v3-ui.md](docs/plugin-v3-ui.md).
-
-`styles` is the **opt-in** for self-hosted CSS (Principle II — prebuilt Tailwind, no Play CDN). Core's `static/tailwind.min.css` only contains classes scanned from core source at build time, so a plugin installed at runtime (community / NAS) that uses classes core didn't scan — especially arbitrary values like `text-[11px]` — renders unstyled. Declaring `styles` makes the frontend inject one versioned `<link rel="stylesheet">` into `<head>` (covering the plugin's screen *and* its settings panel) pointing at the plugin's own compiled stylesheet. The value is a **plugin-root-relative path that must live under `assets/`** (e.g. `"assets/plugin.css"`) so it serves through the sandboxed `/api/plugins/<id>/assets/...` route. Build it with `corePlugins: { preflight: false }` (utilities only — core ships the single base reset; don't duplicate it) and **never** the Tailwind Play CDN. Plugins that use only core-guaranteed utilities, or ship no Tailwind, omit `styles` and are byte-for-byte unaffected. Full authoring guide + scaffold: [docs/plugin-styles.md](docs/plugin-styles.md).
-
-`settings.server_files` is the **opt-in** for the unified Settings export/import flow (slopsmith#113). It's a list of relpaths under `context["config_dir"]` that the plugin wants included in user-triggered backups. A trailing `/` denotes a directory (recurse). Plugins that omit this field have no server-side files exported; their state lives entirely in browser `localStorage`, which is bundled wholesale on every export. Rules:
- Relpaths only. Absolute paths, drive letters, `..` segments, and backslashes are rejected at load time with a `[Plugin]` warning.
- The same allowlist is consulted at both export and import: a bundle that references a file the *importing host*'s manifest no longer declares is skipped with a warning (handles plugin updates between export and import). A bundle that references a file your host's manifest never declared is also skipped — no surprise writes.
- Files are encoded as `{"encoding": "json", "data": <parsed>}` for `.json` files that parse cleanly (diff-friendly), `{"encoding": "base64", "data": "..."}` otherwise (sqlite, model blobs, IRs).
- Plugins own their internal data migration. Importing a bundle whose data schema predates your current code restores bytes verbatim — your plugin must cope at next load.
- Symlinks are skipped on export and never followed on import.
-
-`diagnostics` is the **opt-in** for the troubleshooting bundle (slopsmith#166 — Settings → Export Diagnostics). Two independent fields:
- `diagnostics.server_files` — same allowlist semantics as `settings.server_files`: relpaths under `context["config_dir"]`, no `..`, no abs paths, no backslashes, no leading dots. Files listed here are copied verbatim into `plugins/<plugin_id>/<relpath>` inside the bundle. Use this for snapshot-style state (small DB excerpts, model lists, last-error files).
- `diagnostics.callable` — `"<module>:<function>"` (e.g. `"diagnostics:collect"`). Resolved lazily via `load_sibling` when the user clicks Export, then called as `func({"plugin_id": "...", "config_dir": Path(...)})`. Return `dict`/`list` → written to `plugins/<id>/callable.json`; `bytes` → `callable.bin`; `str` → `callable.txt`. Exceptions are caught and appended to the bundle's `manifest.notes` — a buggy plugin never crashes the export.
-
-Plugins that omit the field contribute nothing to the bundle from the backend side. Frontend plugins can independently push state via `window.slopsmith.diagnostics.contribute(plugin_id, payload)` from their `screen.js` before the user hits Export. Bundle layout + per-file schemas: [docs/diagnostics-bundle-spec.md](docs/diagnostics-bundle-spec.md).
-
-Best practices:
- Embed your own `schema` field (e.g. `"my_plugin.diag.v1"`) in JSON returned by `callable` so future tooling can dispatch by version.
- Keep payloads small (< 100 KB). Diagnostics are not a backup channel — that's `settings.server_files`.
- Don't include user secrets, API keys, or session tokens. The bundle is shared with maintainers / posted to GitHub issues.
-
-`type` is an optional role hint (slopsmith#36). Supported values:
- `"visualization"` — plugin provides a highway renderer. Declaring this makes the plugin eligible for the main-player viz picker AND splitscreen's per-panel picker. Must pair with a `window.slopsmithViz_<id>` factory exporting the setRenderer contract below.
- Absent → no declared role; plugin is loaded and its script runs, but it doesn't appear in role-specific UIs.
-
-**Backend routes** — `routes.py` must export a `setup(app, context)` function. The `context` dict provides:
- `config_dir` — persistent config path
- `get_dlc_dir()` — returns the DLC folder Path
- `extract_meta()` — metadata extraction callable
- `meta_db` — shared MetadataDB instance
- `library_providers` — shared library provider registry for source-aware browsing
- `register_library_provider(provider)` — register a plugin-provided library source. Providers expose `id`, `label`, optional `kind`/`capabilities`, and callable `query_page`, `query_artists`, `query_stats`, and `tuning_names` methods. Providers with `art.read` may also expose `get_art(song_id)` returning one of: a `Response` object (any media type, served as-is); raw `bytes` or `bytearray` (**assumed PNG** — use a `Response` or a `dict` with `content`+`media_type` keys for JPEG/WebP or other formats); a URL string (http/https → 302 redirect; other schemes are rejected with 400); a filesystem path string or `Path` (served as a file with auto-detected media type); or a `dict` with a `url`, `path`, or `content` key. Providers with `song.sync` may expose `sync_song(song_id)` returning `None` (success with no local file) or a `dict` — the dict is passed through as the JSON response and should include `filename`/`local_filename` if a local playable file was produced.
- `unregister_library_provider(provider_id)` — remove a plugin-provided library source by id. The built-in `local` provider cannot be removed.
- `get_sloppak_cache_dir()` — sloppak cache path
- `load_sibling(name)` — loads a sibling module from this plugin's directory under a unique, namespaced module name. See "Sibling imports" below.
- `log` — stdlib `logging.Logger` namespaced to `slopsmith.plugin.<id>`. Pre-configured with the app-wide level, format (including JSON mode), and correlation IDs. Use this for all backend plugin output instead of `print()`. See "Backend plugin logging" below.
-
-**Sibling imports — use `load_sibling`, not bare imports** (slopsmith#33). The plugin loader inserts each plugin's directory onto `sys.path` so `from extractor import X` works, but Python caches imports by **module name** in `sys.modules`. Two plugins that each ship a top-level `extractor.py` (or any other generic name — `util.py`, `client.py`, `parser.py`, `config.py`, …) collide: whichever loads first wins, and the other plugin's `from extractor import X` either gets the wrong module or fails with `cannot import name 'X' from 'extractor'`.
-
-The fix is `context["load_sibling"](name)`, which loads the sibling under a namespaced module name (`plugin_<id>.<name>`, where plugin_id is bijectively encoded so reverse-DNS-style ids like `com.example.foo` work without colliding: `_` -> `_5f_`, `.` -> `_2e_`) so each plugin gets its own copy:
-
-```python
-def setup(app, context):
-    helper = context["load_sibling"]("helper")
-    HelperClass = helper.HelperClass
-    # …
-```
-
-Notes:
- `name` is a bare module name — no `.py` suffix, no slashes, no `.`. The helper raises `ValueError` for path traversal / format issues and `ImportError` for missing files.
- Both single-file siblings (`extractor.py`) and package-form siblings (`extractor/__init__.py`) work. Package form wins when both exist (matches CPython's import-resolution precedence).
- Relative imports between siblings work — `from .shared import X` in a top-level helper, `from ..shared import X` from inside a sibling package. The synthetic parent package `plugin_<id>` carries the plugin directory in its `__path__`.
- `from . import sibling` (attribute-style) also resolves: loaded children are exposed as attributes on the parent package.
- Repeat calls return the cached module. Concurrent first-time calls are serialized via per-module locks so no caller observes a half-initialized module.
- Bare `import sibling` from `routes.py` still works during the transition period, but the loader prints a startup warning when it detects two plugins shipping a same-named top-level module — covering both `.py` files and package directories. Migrate to `load_sibling` to silence the warning and immunize your plugin from future ecosystem collisions. (Don't mix bare imports and `load_sibling` for the same module — they'd execute the file twice and split module-level state.)
-
-**Frontend scripts** — `screen.js` runs in the global scope via a `<script>` tag. It can access `window.playSong`, `window.showScreen`, `window.createHighway`, the `<audio>` element, and the `window.slopsmith` event emitter.
-
-**The playSong wrapper chain** — Plugins commonly wrap `window.playSong` to hook into song playback. Plugins load alphabetically, so the last-loaded (alphabetically later) wrapper runs first, while the alphabetically first plugin runs closest to the original. Be aware that `await` calls in inner wrappers yield to the event loop — WebSocket messages can arrive before outer wrappers finish setup.
-
-## Plugin Best Practices
-
-### v3 UI (fee[dB]ack v0.3.0) — player-chrome contract
-
-v0.3.0 ships a redesigned UI behind a flag (`SLOPSMITH_UI=v3` or the `/v3` route);
-the classic UI (v2) stays the default until 0.3.0 ships, so **plugins must work in
-both**. v3 reuses the same engine (`server.py`, `app.js`, `highway.js`, `playSong`,
-`showScreen`, capabilities, library providers, the `window.slopsmithViz_<id>` /
-`setRenderer` contract), so a plugin's **backend, capabilities, `nav`/`screen`,
-visualization renderers, diagnostics, and settings export work unchanged** — v3
-surfaces `nav` in its sidebar and mounts screens exactly as v2 does.
-
-**The only thing that changed is the player chrome.** If your plugin injects a
-control into it, you must adapt:
-
- v2's wide always-visible `#player-controls` bar is, in v3, a **minimal
-  auto-hiding transport** (fades ~2.5 s after the pointer stills during playback)
-  plus a hover-reveal left icon rail. So injecting into `#player-controls` the
-  legacy way means your control **auto-hides**, and the legacy insertion anchors
-  (`insertBefore` the `span.text-gray-700` separator, or `button:last-child` / ✕
-  Close) **don't exist in v3** → it lands wrong / unreachable.
- **Detect v3** with `window.slopsmith.uiVersion === 'v3'` and **mount into
-  `window.slopsmith.ui.playerControlSlot()`** (a stable, always-reachable container
-  — the "Plugins" rail popover) instead of `#player-controls`. Drop the dead
-  anchors (append), and guard re-injection against the *actual* container
-  (`controls.contains(myBtn)`), not a hard-coded `#player-controls`.
- A host `MutationObserver` re-homes legacy `#player-controls` children into the
-  slot as a fallback, but it **breaks plugins that guard on
-  `#player-controls.contains()`** (the moved node fails the check → re-inject every
-  song). Mount into the slot yourself; don't rely on the shim.
- v3 uses `fb-*` tokens (`fb-card`, `fb-text`, `fb-textDim`, `fb-primary`,
-  `fb-border`) vs v2's `dark-*`/`accent`; legacy classes still render acceptably.
-  Keep `#player` overlay `z-index` ≤ the chrome layers (transport/HUD 20, rail 30,
-  popovers 40).
-
-Full guide + the canonical snippet: **[docs/plugin-v3-ui.md](docs/plugin-v3-ui.md)**.
-Verify any player-injecting plugin in **both** `/` (v2) and `/v3`.
-
-### Performance — never run DOM queries on a per-frame path
-
-Plugins share the main thread with the highway's 60 fps render loop, and during
-playback the highway + note detectors mutate the DOM ~60×/s — so anything that
-*reacts* to DOM changes runs that often too. Work that looks cheap in isolation
-becomes the dominant cost when it runs every frame. A profiled "the 3D highway is
-laggy" report turned out to be **three plugins doing per-frame `querySelectorAll`**
-(~18% of main-thread CPU + NodeList GC churn), not the renderer. The GPU was idle.
-
- **Never call `querySelector` / `querySelectorAll` inside `draw()`, a
-  `requestAnimationFrame` loop, a short `setInterval`, or a `MutationObserver`
-  callback.** Resolve the element(s) **once** when your UI mounts and cache the
-  references; re-resolve only when the cached node is gone (`!el.isConnected`).
-  `querySelectorAll` also allocates a fresh `NodeList` every call → GC pressure at
-  60 fps. (notedetect #75 — a VU meter that `querySelector`'d its bar every tick.)
-
- **Scope `MutationObserver`s narrowly — never `observe(document.body, { subtree:
-  true })` just to notice your own UI's container mount.** A body-subtree observer
-  fires on *every* DOM mutation anywhere, including the per-frame highway churn, so
-  a callback that then scans the document is a per-frame full-DOM scan. Observe the
-  specific container; if it's swapped on screen changes, observe a stable parent,
-  or **cheaply early-bail** (one `getElementById` / a screen-state check) *before*
-  the expensive work. (sloppak-converter #32 — a body-subtree observer re-ran
-  whole-document inject sweeps on every frame of playback.)
-
- **Stop playback-tied loops when their UI is hidden.** An rAF/interval meter (VU,
-  etc.) that keeps drawing while its panel is closed is pure waste — gate it on
-  visibility, or stop and restart it on open/close.
-
- **Per-instance, not global.** Under splitscreen a viz/detector plugin runs
-  multiple instances. Cache refs and resolve panels against your *own* instance's
-  container, never a global `document.querySelector` that could grab a sibling
-  instance's node. (notedetect #75 follow-up.)
-
-These are cheap to get right up front and expensive to retrofit. Profile the
-**main thread**, not the GPU, when a renderer "feels laggy" — the offender is
-usually an unrelated plugin's per-frame DOM work.
-
-### Visualization plugins — two complementary contracts
-
-Slopsmith supports two ways for a plugin to participate in the main player's visuals. They coexist; the setRenderer contract is the default for any viz that draws a highway-shaped surface, and overlays handle layered decorations on top.
-
-**Pick the right shape:**
- Replacing the whole highway drawing on the existing highway canvas (your renderer owns its rendering context / resources; `createHighway()` still owns the canvas element and the rAF loop)? → **setRenderer** (section 1). Enters the viz picker. Works in both the main player and per-panel under splitscreen.
- Adding a layer on top of whichever viz is active? → **Overlay** (section 2). Navbar toggle, not in the picker.
-
-#### 1. setRenderer contract (slopsmith#36) — preferred
-
-Plugins that want to replace the main highway's draw function (per panel, per session) export a renderer factory on `window.slopsmithViz_<id>` where `<id>` matches the `id` in `plugin.json` (`type: "visualization"` required). The factory returns an object matching this shape:
-
-```js
-window.slopsmithViz_my_viz = function () {
-    return {
-        // Required canvas context type. Default '2d' if omitted.
-        // highway.js reads this BEFORE calling init() so it can
-        // replace the underlying <canvas> element if the current
-        // one is locked to a different context type (see "Canvas
-        // context-type swapping" below).
-        contextType: '2d', // or 'webgl2'
-        init(canvas, bundle) {
-            // One-time setup. Own your getContext() call here —
-            // acquire '2d' or 'webgl2' depending on the renderer.
-            // The canvas you receive is guaranteed to either be
-            // unbound or already bound to your declared contextType.
-            this.ctx = canvas.getContext('2d');
-        },
-        draw(bundle) {
-            // Called each requestAnimationFrame tick by the factory.
-            // `bundle` is a snapshot with: currentTime, songInfo, isReady,
-            // notes, chords, anchors (all difficulty-filter-aware),
-            // beats, sections, chordTemplates, stringCount, lyrics,
-            // toneChanges, toneBase, mastery, hasPhraseData, inverted,
-            // lefty, renderScale, lyricsVisible, the 2D coordinate
-            // helpers project and fretX, and getNoteState (see below).
-            // `stringCount` is the active arrangement's string count (4
-            // for bass, 6 for guitar, 7+ for extended-range GP imports —
-            // size string-indexed geometry against this, not a hardcoded
-            // 6). If your renderer needs lefty-aware text rendering, check
-            // bundle.lefty and apply the mirror transform yourself —
-            // a bundle-level helper isn't provided because it would
-            // need your renderer's own context, not the factory's.
-            //
-            // bundle.getNoteState(note, chartTime) (slopsmith#254) — call
-            // this per visible chart note / chord-note to find out whether
-            // a scorer (note_detect) has flagged it 'hit' / 'active' (a
-            // sustain currently being held correctly) / 'miss', so the gem
-            // itself can light up / a held sustain can glow instead of
-            // relying on an overlay ring. Returns null when no provider is
-            // registered or it reports nothing for this note; otherwise
-            // { state: 'hit'|'active'|'miss', alpha: 0..1, color: string|null }.
-            // For chord notes pass the chord's time (note_detect keys its
-            // judgments by `${time}_${string}_${fret}`). 'hit' and 'active'
-            // are both "lit" — a renderer may treat them identically; the
-            // provider owns all fade timing via `alpha` and by simply
-            // ceasing to return state when the effect should end.
-        },
-        resize(w, h) {
-            // Optional. Canvas dims already updated; re-create WebGL
-            // framebuffers / reset 2D transforms here.
-        },
-        destroy() {
-            // Optional. Release resources, remove DOM nodes, null refs.
-            // Called before setRenderer() swaps to another renderer
-            // and on highway.stop().
-        },
-    };
-};
-```
-
-Selecting this plugin in the main-player viz picker — or in splitscreen's per-panel picker — calls `highway.setRenderer(factory())` on the existing highway instance. The built-in 2D highway is the default renderer and is restored by passing nullish — `setRenderer(null)` and `setRenderer(undefined)` both work (the implementation gates on `r == null`). Splitscreen panels create one `createHighway()` per panel and each independently consults the picker, so N panels can run different renderers (or N copies of the same renderer with different arrangements) without coordination.
-
-**Lifecycle contract.** The factory returns a single renderer instance that may go through multiple `init() → ... → destroy()` cycles as the user navigates between songs or screens. Specifically:
-
- `init(canvas, bundle)` runs when the highway has a canvas and the renderer takes over drawing. This is when to acquire `getContext()`, build shaders / meshes / DOM nodes, and register listeners.
- `draw(bundle)` runs on every rAF frame once the WebSocket `ready` message has fired and until the renderer is replaced or the highway stops. It is **not** called during the loading / reconnect window (between `api.init()` + `stop()` and the next `ready`) — that would hand the renderer half-populated chart arrays. Renderers that want to show a "loading" state can read `bundle.isReady` inside a future-widened contract, but today the factory gates `draw` behind the ready flag and `isReady` is only informational once it does fire.
- `destroy()` runs when the renderer is replaced via another `setRenderer(...)` call, OR when `highway.stop()` is called (e.g. the user navigates away from the player). It releases everything `init()` acquired.
- **After `destroy()`, the same instance may receive another `init()` call** — this happens on `playSong()` which does `stop()` → `init()` to reuse the same canvas element for the next song. Renderers must tolerate `init()` being called again on an instance that was previously destroyed. Practically: null your refs in destroy, re-acquire them in init.
- `destroy()` is skipped when it would run on an un-init'd renderer — if a caller does `setRenderer(x)` before the highway ever init'd (possible when restoring a saved picker selection at page load), `x.destroy()` is not called until `x.init()` has run at least once.
- `resize(w, h)` is optional; runs after init and whenever the canvas dimensions change.
-
-**Key rules:**
- The factory **returns a fresh object on each call** — important for splitscreen, where multiple panels will each get an independent instance.
- The renderer **owns its own rendering context** (2D or WebGL). Factory will not call getContext for you.
- **Canvas context-type swapping.** Browsers lock a `<canvas>` to the first context type successfully acquired for its lifetime: once `getContext('2d')` succeeds, `getContext('webgl2')` on that same canvas returns `null`, and vice versa. To let arbitrary 2D ⇄ WebGL renderer swaps work mid-session, `highway.setRenderer()` reads the next renderer's `contextType` before calling its `init()` and, if it differs from the type currently bound, replaces the underlying `<canvas>` element with a fresh one via `oldCanvas.cloneNode(false)` followed by `oldCanvas.replaceWith(newCanvas)`. The factory then calls the renderer's `init(newCanvas, bundle)` with the fresh element so its `getContext()` succeeds. Practical implications:
-  - **What survives the swap.** `cloneNode(false)` preserves *every HTML attribute* on the element — `id`, `class`, inline `style`, all `data-*` and `aria-*` attributes, `role`, `tabindex`, the attribute form of `width`/`height`, and anything else a plugin attached. DOM position is preserved by `replaceWith()`, so siblings, parents, and surrounding layout are unaffected.
-  - **What does NOT survive.** Event listeners attached via `addEventListener` are NOT cloned, and expando properties set imperatively on the JavaScript object (such as the bound rendering context, or any `canvas._myPlugin = …`-style data a plugin attached) are not carried over either. The bound rendering context being left behind on the detached element is exactly what allows the new canvas to start fresh and accept a different `getContext()` call. Note: `canvas.width`/`canvas.height` *are* reflected HTML attributes, so those values do survive the clone; `api.resize()` re-applies the backing-store dimensions on the new element after the swap regardless.
-  - Renderers must **declare `contextType`** on the returned instance (`'2d'` or `'webgl2'`; absent → `'2d'`). Factories may also expose it as a static (`window.slopsmithViz_<id>.contextType = 'webgl2'`) so core can read it before constructing the renderer — used today by Auto-mode evaluation.
-  - Plugins that hold a stale reference to the highway canvas across renderer swaps — including any code that registered listeners directly on the canvas element rather than on `window`/`document` — should listen for the `highway:canvas-replaced` event on `window.slopsmith` and re-acquire / re-register. `window.slopsmith.emit` dispatches a `CustomEvent`, so the payload `{ oldCanvas, newCanvas, contextType }` lives on `event.detail`, not on the event object itself:
-    ```js
-    window.slopsmith.on('highway:canvas-replaced', (event) => {
-        const { oldCanvas, newCanvas, contextType } = event.detail;
-        // re-acquire / re-register against newCanvas
-    });
-    ```
-    Plugins that re-query `document.getElementById('highway')` lazily inside their own event handlers don't need this listener — they pick up the new element automatically (it keeps `id="highway"`).
-  - **`highway:visibility`** — fired on `window.slopsmith` whenever the highway canvas transitions between displayed and hidden. Detection is DOM-based via `canvas.offsetParent === null` (catches `display:none` on the canvas or any ancestor — e.g. splitscreen's `#highway` hide) or whatever a host explicitly sets via `highway.setVisible(bool)`. While `visible === false`, core skips the rAF `renderer.draw(bundle)` call AND the default 2D draw, so renderers don't have to no-op themselves. The event is emitted only on transitions (including the first one after `init()`), not every frame. Payload `{ visible, canvas }` lives on `event.detail`:
-    ```js
-    window.slopsmith.on('highway:visibility', (event) => {
-        const { visible, canvas } = event.detail;
-        // Toggle any sibling DOM your renderer mounts. The 3D Highway
-        // renderer hides its `.h3d-wrap` overlay here so `display:none`
-        // on `#highway` actually hides the visible output.
-    });
-    ```
-    Renderers that only paint to the slopsmith canvas don't need this listener — the rAF skip is enough. Renderers that mount sibling DOM (separate WebGL contexts, overlays, etc.) do.
-  - **`highway.setVisible(bool | null)`** — forces the visibility state regardless of `offsetParent`. Pass `null` to clear the override and resume DOM-based detection. Useful when the host hides the highway via `visibility:hidden`, `opacity:0`, transforms, or clipping rather than `display:none`. The override re-emits any resulting transition immediately rather than waiting for the next rAF tick.
-  - Default-renderer ctx is closure-cached. The replace path nulls the closure ctx so stale draw paths short-circuit; the next default-renderer `init()` re-acquires the 2D context from the new canvas cleanly.
- `draw(bundle)` receives difficulty-filtered arrays — never read from `_filteredNotes` or other internals.
- `_drawHooks` fire for the default 2D renderer (the factory calls them at the end of each frame). Custom WebGL renderers that maintain a 2D overlay canvas (like the bundled 3D highway) also call `window.highway.fireDrawHooks(ctx, W, H)` on that overlay so overlay plugins continue to work regardless of which renderer is active. Custom renderers without a 2D overlay context should not attempt to fire hooks.
-
-**Auto mode — `matchesArrangement(songInfo)` (optional).**
-
-The viz picker prepends an "Auto (match arrangement)" entry that is the default selection on fresh installs. When Auto is active, core evaluates registered viz factories on every `song:ready` and swaps the renderer to the first factory whose `matchesArrangement(songInfo)` predicate returns truthy. No match → the built-in 2D highway.
-
-Declare the predicate as a static on the factory (not the instance) so core can evaluate it without constructing a throwaway renderer:
-
-```js
-window.slopsmithViz_piano = function () { /* ... */ };
-window.slopsmithViz_piano.matchesArrangement = function (songInfo) {
-    return /keys|piano|synth/i.test((songInfo && songInfo.arrangement) || '');
-};
-```
-
- `songInfo` is the highway's live song_info snapshot — `arrangement`, `tuning`, `capo`, `centOffset`, `arrangement_index`, `filename`, `artist`, `title`, etc. May be `{}` before the first song loads.
- Factories without `matchesArrangement` are skipped during auto-selection — the correct default for arrangement-agnostic viz (tabview, jumpingtab) that only make sense as manual picks.
- Explicit picker selections override Auto and are persisted to `localStorage.vizSelection`, so the pinned choice survives page reloads until the user switches back to "Auto" (which also persists). Picking "Auto" re-evaluates against the current song immediately. In contexts where `localStorage` is unavailable (private mode, sandboxed iframes, some test runners) persistence falls back to the current picker `<option>` value, which still overrides Auto for as long as the page stays loaded.
- When an Auto-selected renderer fails and core emits `viz:reverted`, the picker falls back to the built-in default and disables auto-switching until the user re-selects Auto.
- First match wins (picker order), so the registration order of plugins is the tiebreaker. Keep predicates narrow to avoid stealing songs from more specialized viz.
-
-**WebGL viz in Auto mode.** Auto evaluation runs on every `song:ready` regardless of which renderer is active. Auto-installing a WebGL renderer when the canvas is currently 2D — or reverting from a WebGL Auto pick to the default 2D — works without a reload because `setRenderer` swaps the canvas element when `contextType` differs (see "Canvas context-type swapping" above). WebGL viz can therefore safely declare `matchesArrangement` and rely on Auto. For 3D Highway specifically, `_canRun3D()` in app.js still gates Auto from picking it on machines without WebGL2 — that fallback is independent of canvas swapping.
-
-**Per-instance settings for host plugins (slopsmith#849).** A viz provider may declare per-instance controls a consuming host (e.g. splitscreen's per-panel popover) renders generically, by adding a `settings` array to its `capabilities.visualization` manifest block: `[{ key, label, type: "toggle" | "range" | "select", default, min?, max?, step?, options? }]`. This is the capability-native, declarative replacement for the ad-hoc `factory.panelControls` static. The validated list is surfaced through the visualization host's `list-providers` snapshot, so a host reads it without knowing the plugin. **A provider that declares `settings` MUST implement `applySetting(key, value)` on its renderer instance** — the host calls it on the specific per-panel instance, which is inherently per-panel (no canvas→panel resolution, no shared global localStorage keys). `getSetting(key)` is optional (the host falls back to the declared `default`); the host owns persistence. `factory.panelControls` remains read as a legacy fallback for hosts that still consume it, but new viz should declare `settings` + `applySetting`.
-
-#### 2. Overlay contract — for add-on layers
-
-Plugins that add a layer on top of whichever visualization is active — HUDs, fretboard diagrams, chord labels, practice feedback — don't replace the renderer. They manage their own canvas, their own rAF loop, and a toggle button somewhere visible (typically a navbar pill), reading public highway state via the getters:
-
- `highway.getTime()` / `highway.getBeats()` — current playback position
- `highway.getNotes()` / `highway.getChords()` — raw arrays containing every note/chord in the chart regardless of the current difficulty level
- `highway.getFilteredNotes()` / `highway.getFilteredChords()` — difficulty-filtered variants. Returns the master-difficulty-filtered arrays when the song has phrase-level data (slider active); falls through to the raw arrays for songs with a single difficulty level (slider disabled). Plugins that process only the notes the player is currently expected to play should use these instead of `getNotes()` / `getChords()`
- `highway.hasPhraseData()` — returns `true` when the current song has phrase-level difficulty ladder data (i.e. the mastery slider is active and `getFilteredNotes()` / `getFilteredChords()` return a filtered subset). Use this to gate logic that only makes sense when difficulty filtering is available
- `highway.getPhrases()` — phrase timing windows `[{ index, start_time, end_time, max_difficulty }]` for the current song's difficulty ladder. Returns `null` when phrase data is absent (GP imports, single-difficulty charts). Read-only; do not mutate. Pair with `hasPhraseData()` to gate phrase-aware logic.
- `highway.getMastery()` — current master-difficulty slider value as a fraction `0..1`. Reflects the same value the mastery slider is set to; meaningful only when `hasPhraseData()` is true.
- `highway.getChordTemplates()` — chord shape lookup table; index by `chord.id` from `getChords()` to get `{ name, fingers, frets }`. `fingers` and `frets` are per-string arrays (length matches the tuning's string count); within `fingers`, `-1` = unused, `0` = open string, `n > 0` = finger number. arrangement XML sources populate real fingerings; GP imports currently emit all `-1` since pre-import sources don't carry finger data. Not filter-aware: templates are static metadata, every `chord_id` referenced by `getChords()` is guaranteed valid
- `highway.getSongInfo()` — tuning, arrangement, capo
- `highway.getStringCount()` — number of strings on the active arrangement (4 for bass, 6 for guitar, 7+ for extended-range GP imports). Derived server-side as `max(notes-max-string + 1, name-based fallback, len(tuning))` where the tuning length only contributes when it isn't the arrangement XML padded 6-string form (sloppak / GP-imported sources carry trimmed tuning lengths). The name-based fallback is 4 for arrangements containing "bass" (case-insensitive) and 6 otherwise. This combination handles partial-string-usage charts (a 6-string lead that never plays string 5), extended-range GP imports (5-string bass, 7-string guitar), and sloppaks that explicitly encode the instrument range — without requiring plugins to do their own arrangement-name matching
- `highway.getLefty()` / `highway.getInverted()` — mirror + invert state
-
-Overlays do NOT appear in the viz picker and do NOT declare `"type": "visualization"` in `plugin.json`. They coexist with whichever renderer (default 2D, 3D highway, piano, ...) the user has picked.
-
-**Key rules:**
- **Own your rAF + canvas** — don't piggyback on `_drawHooks` or on `createHighway`'s rendering context. Draw hooks fire for the default 2D renderer and for custom renderers that explicitly call `window.highway.fireDrawHooks(ctx, W, H)` (e.g. the bundled 3D highway fires them on its 2D overlay canvas), but not for every custom renderer.
- **Re-read state every frame** — overlay output must track whatever the current renderer is drawing. Don't cache note positions across frames.
- **Respect lefty + invert toggles** — if the overlay depicts strings or frets, mirror using the same transforms the active renderer would.
- **If you position with `highway.project` / `highway.fretX` (the 2D-highway geometry), gate on `highway.isDefaultRenderer()`** — those helpers describe the *built-in 2D* highway's depth curve and fret zoom. When a custom renderer (3D highway, piano, …) is active your draw hook still fires (on that renderer's 2D overlay layer), but those coordinates won't match its scene — markers land in arbitrary places. Skip rendering when `isDefaultRenderer()` is false; the custom renderer owns that feedback. Renderer-agnostic overlays (fretboard diagram, chord-label HUD — they use `getNotes()`/`getChordTemplates()` + their own layout) don't need this guard.
- **Clean up on toggle-off** — cancel rAF and remove/hide the overlay canvas so inactive overlays aren't wasting frames.
-
-Reference: [fretboard plugin](https://github.com/got-feedback/feedback-plugin-fretboard) — canonical overlay implementation (navbar toggle, own canvas, 80ms active-note window).
-
-**Why two?** setRenderer plugs into an existing highway — main-player or splitscreen-panel — reusing its WebSocket and data parsing, so the common "I want a different look for the same data" case is zero boilerplate AND multi-instance for free. Overlays compose with whatever renderer is active — they decorate rather than replace, so multiple can stack (fretboard + chord labels + practice feedback) without fighting over the canvas.
-
-A previous standalone-pane contract (`window.createMyVisualization({ container })` with its own WebSocket per pane) was used by splitscreen pre-Wave-C. It's been retired now that splitscreen calls `setRenderer` on per-panel `createHighway()` instances; if you find references in older plugin docs or external integration guides, those describe the legacy path.
-
-#### 3. Note-state provider — for scorers that want renderers to "light up" notes (slopsmith#254)
-
-A scoring plugin (note_detect) can publish a per-note judgment so whichever renderer is active draws the **gem itself** lit on a correct hit, and keeps a sustain trail glowing while it's still being played correctly — instead of a separate overlay ring floating near the note.
-
-```js
-// In the plugin (after resolving the highway instance):
-highway.setNoteStateProvider((note, chartTime) => {
-    // `note` is the chart note object ({ t, s, f, sus, ... }); for chord
-    // notes `chartTime` is the chord's time. Return one of:
-    //   - falsy  → no special state (render normally)
-    //   - 'hit'    — struck correctly; renderer lights the gem
-    //   - 'active' — a sustained note is right now being held correctly
-    //   - 'miss'   — missed; renderer may red-wash the gem
-    //   - { state: <one of the above>, alpha?: 0..1, color?: '#rrggbb' }
-    // You own all fade timing: return a decaying `alpha` for a struck-note
-    // glow, `alpha: 1` (or a bare string) for a held sustain, and stop
-    // returning state when the effect should end. Keep it cheap — it's
-    // called per visible note per renderer per frame.
-});
-// On teardown:  highway.setNoteStateProvider(null);
-```
-
- Only one provider is active at a time (last `setNoteStateProvider` wins). `highway.getNoteStateProvider()` returns the current one (or null).
- The built-in 2D highway consults it in `drawNote` / `drawSustains` / the chord-frame path: 'hit'/'active' → bright string colour + additive halo + a contained "sizzle" (crackling sparks, throbbing core, a shockwave ring on a fresh strike) on the gem and a bright (vs dim) sustain trail; 'miss' → faint red wash. The bundled **3D highway** reads the same data via `bundle.getNoteState` (bright string-tinted outline + bright body + glowing sustain + a contained sparkle hugging the note rect on hit/active; red outline + suppressed body on miss). Custom renderers that want it call `bundle.getNoteState(note, chartTime)` — it null-guards and returns the normalized `{ state, alpha, color }` (or null).
- This is orthogonal to the overlay contract: note_detect remains an overlay (HUD, diagnostic miss markers, the "currently detected" indicator) *and* a scorer that feeds this provider. A renderer that ignores `getNoteState` simply doesn't light gems — nothing breaks.
-
-### Audio mixer fader registration (slopsmith#87)
-
-Plugins that produce audio outside the song's `<audio>` element (NAM amp output, synth voices, etc.) can register a labeled fader so users can balance them against the song from one mixer popover in the player controls.
-
-```js
-function _registerFader() {
-    const api = window.slopsmith && window.slopsmith.audio;
-    if (!api) return;
-    api.registerFader({
-        id: 'my_plugin',           // unique key
-        label: 'My Plugin',        // shown above the fader
-        unit: 'dB',                // optional suffix shown next to the value (e.g. '%', 'dB')
-        min: 0, max: 2, step: 0.05,
-        defaultValue: 1.0,
-        getValue: () => _myCurrentVolume,        // read current value
-        setValue: (v) => _setMyVolume(v),         // write + persist + apply
-    });
-}
-
-if (window.slopsmith && window.slopsmith.audio) {
-    _registerFader();
-} else {
-    window.addEventListener('slopsmith:audio:ready', _registerFader, { once: true });
-}
-```
-
-The plugin owns persistence — the registry calls `getValue()` when the popover opens, and also after each `setValue()` during slider drags to re-sync the displayed value. Keep `getValue()` cheap and side-effect-free, and make sure `setValue()` updates whatever backing state `getValue()` reads synchronously. Pair `setValue` with whatever your plugin already does internally (write the GainNode, persist to localStorage, update any in-plugin label). Use `unregisterFader(id)` when your plugin is teardown-able and you want the strip to disappear; otherwise keep it registered so the user's setting persists across toggle states.
-
-### Backend plugin logging
-
-Use `context["log"]` for all backend plugin output. It is a stdlib `logging.Logger` namespaced to `slopsmith.plugin.<id>`, pre-configured with the app-wide level, format (including JSON mode), and correlation IDs. Never use `print()` — it bypasses correlation context and log rotation.
-
-```python
-def setup(app, context):
-    log = context["log"]
-    log.info("plugin ready")
-    log.warning("optional dependency %r not found, feature disabled", dep)
-    try:
-        risky_init()
-    except Exception:
-        log.exception("unhandled error during setup")  # auto-captures traceback
-```
-
-For CLI entry points (scripts that also run as `__main__`), add a stdlib fallback so the logger works without the server pipeline:
-
-```python
-if __name__ == "__main__":
-    import logging
-    logging.basicConfig(level=logging.INFO, format="%(levelname)s %(message)s")
-```
-
-### Diagnostics contribution from frontend (slopsmith#166)
-
-Plugins that hold useful debug state in the browser (active model name, last user input, internal counters) can push it into the diagnostics bundle by calling `window.slopsmith.diagnostics.contribute(plugin_id, payload)` at any time. The contribution API is idempotent — repeated calls overwrite the previous value. Whatever was last contributed before the user hits Export Diagnostics is what lands in `plugins/<plugin_id>/client.json`.
-
-```js
-window.slopsmith.diagnostics.contribute('my_plugin', {
-    schema: 'my_plugin.client_diag.v1',
-    active_preset: getActivePreset(),
-    last_error: _lastError,
-});
-```
-
-Loaded from `static/diagnostics.js` ASAP in `<head>` so the console-wrap is in place before any other script runs. Available on the `window.slopsmith.diagnostics` namespace alongside `snapshotConsole()`, `snapshotHardware()`, `snapshotUa()`, `snapshotLocalStorage()`, `snapshotContributions()`. Keep your payload small (< 100 KB) and don't include secrets — bundles are shared with maintainers.
-
-### Keyboard Shortcuts
-
-Plugins can register keyboard shortcuts via the global `window.registerShortcut()` function. Shortcuts appear in the `?` help panel.
-
-```js
-window.registerShortcut({
-    key: 'k',                       // key value (e.key) or key code (e.code)
-    description: 'Toggle my view',  // shown in the help panel
-    scope: 'player',                // 'global' | 'player' | 'library' | 'settings' | 'plugin-{id}'
-    condition: () => _isMyViewActive, // optional guard
-    handler: (e) => _myAction()      // called when shortcut triggers
-});
-```
-
-**Scope** controls when the shortcut is active:
- `global` — works on any screen
- `player` — only on the player screen
- `library` — only on the home/favorites screens
- `settings` — only on the settings screen
- `plugin-{id}` — only when your plugin's screen is active
-
-**Panel-scoped shortcuts:** For plugins that create multiple panels (e.g., splitscreen), shortcuts are automatically scoped to the active panel. Use `const panel = window.createShortcutPanel(id)` to create a panel (it returns the panel object — keep the reference so you can call `panel.clearShortcuts()` during cleanup) and `window.setActiveShortcutPanel(id)` to switch between them. Each panel has its own shortcut registry, so multiple panels can have the same key without collisions.
-
-**Condition** is an optional guard function. If it returns false, the shortcut is skipped even if in scope.
-
-**Key matching:** The handler matches against both `e.key` (character produced) and `e.code` (physical key). Use `e.key` for letters/symbols that depend on keyboard layout, and `e.code` for special keys (e.g. `Space`, `ArrowLeft`).
-
-**Built-in shortcuts:**
-
-| Key | Description |
-|-----|-------------|
-| `?` | Show keyboard shortcuts panel (global) |
-| `Space` | Play/Pause (player only) |
-| `←` / `→` | Seek ±5 seconds (player only) |
-| `Escape` | Back to library (player only) |
-| `[` / `]` | Audio offset ±10ms (Shift: ±50ms) (player only) |
-
-**Debugging:** Open browser console and type `_listShortcuts()` to inspect registered shortcuts.
-
-### General plugin guidelines
-
- Wrap your plugin code in an IIFE: `(function () { 'use strict'; ... })();`
- Use `localStorage` for user-facing settings, prefixed with your plugin id
- If hooking `window.playSong`, always call the original and `await` it
- If hooking `window.showScreen`, clean up your state when leaving the player screen
- Use `window.slopsmith.emit()` / `window.slopsmith.on()` for inter-plugin communication
- Use `window.registerShortcut()` to add keyboard shortcuts. Clean up with `window.unregisterShortcut(key, scope)` — pass the same scope you registered with, since the default is `'global'` and won't match `player`/`library`/`settings`/`plugin-*` bindings. For panel-scoped shortcuts, prefer `panel.clearShortcuts()`.
-
-## Song Formats
-
-Slopsmith supports two song formats:
-
-### Loose folder (XML charts)
-A directory containing arrangement XML plus an audio file (and optional `manifest.json` + album art). Discovered, indexed, and played directly — see `lib/loosefolder.py`. Metadata follows a `manifest.json` → XML tags → folder-name priority chain. Songs are tagged `format: "loose"` in the library.
-
-### Sloppak (open format)
-An open, hand-editable song package designed for Slopsmith. Exists in two interchangeable forms:
- **Zip archive** (`.sloppak` file) — distribution form
- **Directory** (`.sloppak/` folder) — authoring form
-
-**Contents:**
-```
-manifest.yaml          Song metadata (title, artist, album, duration, tuning, arrangement IDs, ...)
-arrangements/
-  lead.json            Note/chord/anchor data in wire format (see song.py)
-  rhythm.json          Files here are driven by manifest.yaml arrangement entries
-  ...                  (e.g. arrangements/<arrangement-id>.json)
-stems/
-  full.ogg             Mixed audio (always present)
-  guitar.ogg           Individual stems (optional, from Demucs split)
-  bass.ogg
-  drums.ogg
-  vocals.ogg
-  piano.ogg
-  other.ogg
-cover.jpg              Album art (optional)
-lyrics.json            Syllable-level lyrics (optional)
-```
-
-Sloppak is the preferred format for new features. The [Stems plugin](https://github.com/topkoa/slopsmith-plugin-stems) provides live stem mixing for sloppak songs.
-
-**Full developer reference:** [docs/sloppak-spec.md](docs/sloppak-spec.md) — manifest schema, arrangement wire format, and how to extend the format with new data types (drum tab, key/scale annotations, etc.).
-
-**Key code:**
- `lib/sloppak.py` — format detection, zip/directory resolution, metadata extraction, song loading
- `lib/sloppak_convert.py` — sloppak assembly pipeline, Demucs stem splitting
- `lib/song.py` — shared data models (`Note`, `Chord`, `Arrangement`, `Song`) and wire format serialization used by both formats
-
-## Frontend Conventions
-
- **No frameworks** — vanilla JS, fetch API, DOM manipulation
- **Globals** — `highway`, `audio`, `playSong()`, `showScreen()`, `createHighway()`, `window.slopsmith`
- **Storage** — `localStorage` for all user preferences
- **Styling** — Tailwind CSS utility classes, dark theme (`bg-dark-600`, `text-gray-300`, accent `#4080e0`, gold `#e8c040`). Tailwind is served as a **prebuilt** stylesheet (`static/tailwind.min.css`, regenerated by `bash scripts/build-tailwind.sh`), **never** the runtime Play CDN — the CDN's on-the-fly JIT rescanned the DOM on the main thread and dropped ~26% of frames with the 3D highway (slopsmith-desktop#110). The committed CSS only contains classes the build scanner saw, so CI (`tailwind-fresh`) rebuilds and diffs it; run the build script and commit when you add new classes. A plugin that uses classes not guaranteed in core (notably arbitrary values like `w-[37px]`) MUST ship its own compiled stylesheet via the `styles` manifest key, built with `corePlugins.preflight = false` (utilities only — core ships the one base reset). Plugins MUST NOT load the Tailwind Play CDN or any runtime CSS JIT. See constitution Principle II.
- **Naming** — camelCase for JS functions, kebab-case for CSS classes, snake_case for plugin IDs
- **Player layout** — `#player` is `display:flex; flex-direction:column; position:fixed; inset:0`. `#highway` is `flex:1`. `#player-controls` sits at the bottom. Hiding the highway collapses the layout — use `margin-top: auto` on controls if you need to hide it.
-
-## Backend Conventions
-
- **Framework** — FastAPI with uvicorn
- **Imports** — flat imports from `lib/` (no package `__init__.py`): `from song import Song`
- **Database** — SQLite via MetadataDB class with `threading.Lock` for thread safety
- **WebSocket** — JSON frames, try/except `WebSocketDisconnect`
- **Error handling** — graceful fallbacks (audio conversion errors don't crash the song, missing art returns placeholder)
- **Type hints** — used sparingly (`Path | None`, `dict`, `list`)
- **Docstrings** — minimal; code is self-documenting
-
-## Testing
-
-```bash
-pytest                         # Run all tests
-pytest tests/test_song.py -v   # Specific file
-pytest -k "round_trip" -v      # Pattern match
-```
-
- Framework: pytest
- Config: `pyproject.toml` sets `pythonpath = [".", "lib"]` and `testpaths = ["tests"]`
- CI: GitHub Actions runs pytest on push/PR to main (Python 3.12)
- Test dependencies: `requirements-test.txt`
-
-## Tuning the note_detect plugin
-
-Detection quality is hard to judge by eye — a player UI that "feels worse" after a code change isn't a regression you can defend in review. The plugin ships with a record-replay-sweep workflow so changes to the detector, the matcher, or the user's environment (A/V offset, latency, channel) can be measured against a single reference take.
-
-Quick orientation:
- **Reference recording** lives in the gear popover on the player (gated behind Settings → Note Detection → "Detection tuning (advanced)"). Arm before pressing Play; auto-saves a WAV to `static/note_detect_recordings/` on song-end. The directory is bind-mounted, so the host-side harness can read it without a copy step.
- **Benchmark sloppak** ships in-tree at [docs/benchmarks/note_detect_v1/note_detect_benchmark_v1.sloppak](docs/benchmarks/note_detect_v1/note_detect_benchmark_v1.sloppak) — 8 sections each isolating a different failure mode (low-freq mono, sustained holds, hammer/pull, power chords, dense open chords, bends). Drop it directly into your sloppak DLC folder to install (don't rename — slopsmith keys off the `.sloppak` suffix even though the file is a zip under the hood). The unzipped form lands at `static/sloppak_cache/note_detect_benchmark_v1.sloppak/` after first play. Builder: [docs/benchmarks/note_detect_v1/build_benchmark.py](docs/benchmarks/note_detect_v1/build_benchmark.py).
- **Headless harness** at [`tools/harness.js`](https://github.com/got-feedback/feedback-plugin-notedetect/blob/main/tools/harness.js) in the note_detect plugin's own repo (cloned into `plugins/note_detect/` locally) runs the same `processFrame` / `matchNotes` / `checkMisses` code path off Node, in seconds per run. Same `note_detect.diagnostic.v1` schema as the in-app Download Diagnostic button.
- **A/V auto-calibrate** (Settings → Note Detection) reads `timing_error_ms_hits.median` and proposes the av-offset that drives it to zero. Iterative: usually converges in 2–3 Apply rounds.
-
-**Always record at 1.0× playback speed** — half-speed takes produce all-miss garbage because chart times are absolute. **Always use `timing_error_ms_hits` (not all-matched) as a calibration signal** — the all-matched median pins near a constant when the offset is wrong, because the matcher silently snaps to neighbouring chart notes.
-
-Full developer reference (workflow recipes, harness flag table, diagnostic schema, common pitfalls): [docs/note-detect-tuning.md](docs/note-detect-tuning.md).
-
-## Versioning
-
- **`VERSION`** (repo root) — single source of truth; plain semver string (e.g. `0.2.4`). Bind-mounted into the container and copied by the Dockerfile so it's always available at `/app/VERSION`.
- **`GET /api/version`** — returns `{"version": "<contents of VERSION>", "source_url": "...", "license_url": "..."}`. The version drives the navbar badge; `source_url` / `license_url` populate the Settings → About links. `source_url` is configurable via the `APP_SOURCE_URL` env var (default `https://github.com/got-feedback/feedback`); `license_url` falls back to `source_url + "/blob/main/LICENSE"` (GitHub-style, default branch `main`) and is overridable via the `APP_LICENSE_URL` env var — set it explicitly when the source is hosted on a non-GitHub forge (GitLab/Gitea/self-hosted) or under a non-`main` default branch. Both env values must be `http(s)`; non-http(s) values are rejected and fall back to the safe default to prevent `javascript:`/`data:` hrefs.
- **Auto-sync** — `.github/workflows/sync-version.yml` rewrites `VERSION` via a `repository_dispatch` (`desktop-released`) fired from `slopsmith-desktop`'s release job. As an explicit automation-only exception to the "Never push directly to main" rule in Git Workflow below, the sync job commits straight to `main` as `github-actions[bot]` (version bumps are mechanical; the PR round-trip adds no signal). Human contributors must still go through feature branches + PRs. No manual VERSION edits needed. Use the workflow's `workflow_dispatch` trigger with `version: X.Y.Z` for manual runs (recovery / out-of-band bumps).
- **`CHANGELOG.md`** — follows [Keep a Changelog](https://keepachangelog.com/) format. Update the `[Unreleased]` section with each PR; when `slopsmith-desktop` cuts a release, rename `[Unreleased]` to the new version + date (the VERSION bump itself is automated).
-
-## Git Workflow
-
- **Never push directly to main** — always create a feature branch and open a PR
- **Upstream remote** — set `upstream` to the canonical Slopsmith repository; `origin` is your fork
- **Plugins are gitlinks** — each plugin in `plugins/` is typically its own git repo (submodule or clone). Branch switches on the main repo can clobber plugin directories. Use `git update-index --assume-unchanged` for plugin dirs if needed.
- **Commit style** — short imperative subject line, blank line, then body explaining *why*
-
-## WebSocket Protocol Reference
-
-The highway WebSocket at `/ws/highway/{filename}?arrangement={index}` streams these messages in order:
-
-| Message | Shape | Description |
-|---------|-------|-------------|
-| `loading` | `{ type: 'loading', stage }` | Status/progress message during extraction or conversion |
-| `song_info` | `{ type, title, artist, arrangement, arrangement_index, arrangements, duration, tuning, capo, centOffset, format, audio_url, audio_error, stems }` | Song metadata. `arrangements` is the full list for the switcher. `audio_url` is `null` when audio is unavailable, in which case `audio_error` is non-null; otherwise `audio_error` is `null`. `stems` is always present — an empty array for non-sloppak songs or sloppak songs with no split stems. `tuning` is an array (6 for guitar, 4 for bass). `centOffset` is a float (cents) from the RS2014 `<centOffset>` field — commonly `-1200.0` for extended-range bass (one octave down), small non-zero values for true-tuned content (e.g. A443 ≈ +11.8 cents), `0.0` when absent. Available via `getSongInfo().centOffset`. |
-| `beats` | `{ type, data: [{ time, measure }] }` | Beat timestamps with measure numbers |
-| `sections` | `{ type, data: [{ time, name }] }` | Named sections (Intro, Verse, Chorus, etc.) |
-| `anchors` | `{ type, data: [{ time, fret, width }] }` | Fret zoom anchors |
-| `chord_templates` | `{ type, data: [{ name, frets: [6] }] }` | Named chord shapes |
-| `lyrics` | `{ type, data: [{ w, t, d }], source }` | Syllables: `w`=word, `t`=time, `d`=duration. `-` joins to previous, `+` = line break. `source` is one of `"xml"`, `"whisperx"`, `"user"` — UI can use it to render an "auto-transcribed" badge for `whisperx`. Sloppaks always include `source` (legacy sloppaks without a `lyrics_source` manifest key default to `"xml"` at load time). Loose folders set it based on which extractor matched. Absent only when no lyrics fired the message at all |
-| `tone_changes` | `{ type: 'tone_changes', base, data: [{ time, name }] }` | Optional — tone change events relative to the arrangement base tone; only sent if tones were found |
-| `notes` | `{ type, data: [{ t, s, f, sus, ho, po, sl, bn, ... }] }` | Single notes |
-| `chords` | `{ type, data: [{ t, notes: [{ s, f, sus, ... }] }] }` | Chord events |
-| `phrases` | `{ type, data: [{ start_time, end_time, max_difficulty, levels: [{ difficulty, notes, chords, anchors, handshapes }] }], total }` | Optional — per-phrase difficulty ladder for master-difficulty slider (slopsmith#48). Only sent when the source chart carries multi-level phrase data (phrase-aware sloppak). Sent in chunks (`data` is a batch, `total` is the full count across messages) to avoid multi-MB single frames. Absent for GP imports and legacy sloppak; consumers must treat missing message as "single fixed difficulty — slider disabled". |
-| `ready` | `{ type: 'ready' }` | All data sent — safe to finalize and start rendering |
-
-Message delivery is incremental. You may receive `loading` updates and `lyrics` before note/chord payloads; `tone_changes` comes after `lyrics` when present and may be omitted entirely. Do not finalize rendering until you receive `ready`.
-
-## Common Pitfalls
-
-1. **playSong wrapper race condition** — The wrapper chain runs outermost-first (last-loaded wrapper runs first). If an inner plugin (e.g. `3dhighway`) does `await import(CDN)`, it yields to the event loop. WebSocket messages (`song_info`, `ready`) can arrive before outer plugins set their callbacks. Use `getSongInfo()` as a fallback rather than relying solely on `_onReady`.
-
-2. **Plugin gitlinks** — Plugins are separate git repos cloned into `plugins/`. Switching branches on the main repo can delete or clobber these directories. Be careful with `git checkout` and `git clean`.
-
-3. **Highway flex layout** — `#highway` has `flex:1` in the player. Hiding it with `display:none` removes the flex child, causing `#player-controls` to float to the top. If you hide the highway, add `margin-top: auto` to the controls div to keep it at the bottom.
-
-4. **Multiple WebSocket connections** — The server supports many simultaneous WebSocket connections to the same song. Split screen panels, lyrics panes, and jumping tab panes each open their own. This is by design — don't try to multiplex.
-
-5. **Plugin load order** — Plugins load alphabetically by directory name. This determines the `playSong` wrapper chain order and which plugin's UI elements appear first. If your plugin depends on another's globals, check at runtime (`typeof window.X === 'function'`), not at load time.
+Everything you'd expect to find here - architecture, running the app, testing, conventions, plugin authoring, first-hour pitfalls - is imported above via `@AGENTS.md`. Updates go in `AGENTS.md`. This file only carries Claude-Code-specific automation references.
@@ -26,7 +26,7 @@ If you forget to sign off, amend the most recent commit with `git commit --amend

 ## Plugin licensing

-Plugins live in their own repositories and are loaded at runtime — see the [Plugin System section in CLAUDE.md](CLAUDE.md) for the technical contract, and [Plugin Best Practices](CLAUDE.md) for the conventions every plugin should follow (v2/v3 player chrome, the visualization contracts, and the **performance rules** — no per-frame DOM queries or broad `document.body` `MutationObserver`s — that keep the 60 fps highway smooth). Plugins are not subject to AGPL by being loaded into Slopsmith (the loader runs them as separate Python modules / browser scripts), but for the **curated plugin list** to accept your plugin we ask that it be released under an AGPL-3.0-compatible license:
+Plugins live in their own repositories and are loaded at runtime — see [`docs/PLUGIN_AUTHORING.md`](docs/PLUGIN_AUTHORING.md) for the technical contract and [`schema/plugin.schema.json`](schema/plugin.schema.json) for the manifest schema. Plugins are not subject to AGPL by being loaded into Slopsmith (the loader runs them as separate Python modules / browser scripts), but for the **curated plugin list** to accept your plugin we ask that it be released under an AGPL-3.0-compatible license:

 - AGPL-3.0-only or AGPL-3.0-or-later
 - GPL-3.0-only or GPL-3.0-or-later
@@ -41,7 +41,7 @@ Plugins under GPL-2.0-only, LGPL-2.1-only, CDDL, EPL, or proprietary terms will

 ## Workflow

-Standard PR workflow described in [CLAUDE.md → Git Workflow](CLAUDE.md):
+Standard PR workflow described in [AGENTS.md → Git workflow](AGENTS.md#git-workflow):
 - Never push directly to `main`.
 - Create a feature branch on your fork.
 - Open a PR against `got-feedback/feedback:main`.
@@ -0,0 +1,61 @@
+# Plugin Authoring Guide
+
+Slopsmith's plugin system is the primary extension point. Each plugin lives in `plugins/<name>/` with a `plugin.json` manifest that declares the capability domains, UI contributions, settings metadata, diagnostics, and runtime files the plugin participates in.
+
+This guide is the entry point. Each topic below has a dedicated doc — read what's relevant to what you're building.
+
+## Quickstart
+
+```text
+plugins/my_plugin/
+├── plugin.json          Manifest (required) — see docs/plugin-manifest.md
+├── screen.html          Optional — UI declared through `ui` contributions
+├── screen.js            Optional — hydrates declared frontend capabilities
+├── routes.py            Optional — backend provider/requester implementation
+├── settings.html        Optional — settings UI declared through `ui.settings`
+└── requirements.txt     Optional — pip deps auto-installed on load
+```
+
+Start every plugin by describing its Slopsmith-facing behavior in the manifest with `standards: ["capability-pipelines.v1"]`, native `capabilities`, and redaction-safe `ui` metadata. A plugin with no app-facing behavior beyond metadata can still be this small:
+
+```json
+{
+  "id": "my_plugin",
+  "name": "My Plugin",
+  "version": "0.1.0"
+}
+```
+
+Capability declarations are the source of truth for diagnostics, the Capability Inspector, and plugin tooling. Treat missing capability metadata as an intentional exception for metadata-only or transitional plugin manifests.
+
+## Topics
+
+| Topic | Doc | When to read |
+|---|---|---|
+| **Manifest reference** | [plugin-manifest.md](plugin-manifest.md) | Field-by-field reference for `plugin.json`. Read first. |
+| **Capability declarations** | [plugin-manifest.md#capabilities](plugin-manifest.md#capabilities) | Declaring provider/requester/observer intent with `capability-pipelines.v1`. |
+| **Capability domains** | [capability-domains.md](capability-domains.md) | Active domains, planned domains, and promotion rules. |
+| **Capability recipes** | [capability-recipes.md](capability-recipes.md) | Copyable manifest patterns for provider/requester/observer plugins. |
+| **Visualization contracts** | [plugin-visualization-contracts.md](plugin-visualization-contracts.md) | Building a highway renderer (setRenderer), an overlay layer, or a note-state provider. |
+| **Plugin styles** | [plugin-styles.md](plugin-styles.md) | Shipping a plugin-owned prebuilt stylesheet via `styles: "assets/plugin.css"`. |
+| **Backend logging** | [plugin-logging.md](plugin-logging.md) | Plugin has a `routes.py`. Use `context["log"]`, never `print()`. |
+| **Diagnostics contribution** | [plugin-diagnostics.md](plugin-diagnostics.md) | Adding plugin state to the Export Diagnostics bundle. |
+| **Sibling Python imports** | [plugin-sibling-imports.md](plugin-sibling-imports.md) | Multi-file backend plugins. Use `context["load_sibling"]`. |
+| **WebSocket protocol** | [websocket-protocol.md](websocket-protocol.md) | Plugins that read the highway stream directly. |
+| **Testing plugins** | [testing-plugins.md](testing-plugins.md) | Conftest fixtures and Playwright patterns for plugin tests. |
+| **Diagnostics bundle spec** | [diagnostics-bundle-spec.md](diagnostics-bundle-spec.md) | Existing in-depth spec — what's inside a diagnostics export. |
+| **Sloppak format spec** | [sloppak-spec.md](sloppak-spec.md) | Existing in-depth spec — for plugins that read/write sloppaks. |
+
+## General guidelines
+
+- Wrap your plugin code in an IIFE: `(function () { 'use strict'; ... })();`
+- Declare `standards: ["capability-pipelines.v1"]` and native `capabilities` for the plugin's Slopsmith-facing behavior.
+- Use `ui` / `ui_contributions` for plugin-owned UI surfaces so the host can attribute them in diagnostics and support bundles.
+- Use `localStorage` for user-facing settings, prefixed with your plugin id.
+- Prefer native capability commands, events, and provider registration over private globals. If a domain you need is not active yet, document the gap in the PR instead of baking in a new private integration.
+
+## Licensing for curated plugins
+
+Plugins submitted for inclusion in Slopsmith must use AGPL-3.0-only. See [CONTRIBUTING.md](../CONTRIBUTING.md) for the full policy. The `plugin.json` schema enforces this via the `license` field enum — see [plugin-manifest.md](plugin-manifest.md).
+
+Add an `SPDX-License-Identifier: AGPL-3.0-only` comment to plugin source files (`screen.js`, `routes.py`, helper modules, and similar authored code) so the manifest license and source-file metadata stay aligned.
@@ -16,7 +16,7 @@ Only declare `plugin-runtime-idempotent.v1` when repeated script hydration canno

 ## UI Contributions

-Legacy `nav`, `screen`, and `settings` fields still work through the existing plugin loader. PR1 keeps UI capability domains out of the runtime graph, so migrated plugins should not treat `ui.navigation`, `ui.plugin-screens`, or `settings` as active capability contracts yet. Their candidate manifest shape is reserved for a future UI-host PR:
+New plugin UI should declare stable `ui` contribution metadata so diagnostics and support tools can attribute surfaces before runtime code hydrates. The runtime host for UI placement is still promoted by a future UI-host PR, but manifests can use the candidate shape now:

 ```json
 {
@@ -28,25 +28,30 @@ Legacy `nav`, `screen`, and `settings` fields still work through the existing pl
 }
 ```

-Core continues to load legacy UI fields normally. It does not emit PR1 compatibility shim entries for UI placement or visualization `type`; the PR that promotes those domains will own their shim accounting and tests.
-
 ## Runtime Domains

-Declare non-UI runtime surfaces under `domains` or `runtime_domains`:
+Declare non-UI runtime surfaces under `capabilities`:

 ```json
 {
-  "domains": {
-    "library": { "role": "provider" }
+  "capabilities": {
+    "library": {
+      "roles": ["provider"],
+      "operations": ["query-page", "query-artists", "query-stats"],
+      "mode": "active",
+      "compatibility": "none",
+      "safety": "safe",
+      "version": 1
+    }
  }
 }
 ```

-If a plugin still uses `routes`, the backend loader continues to load `routes.py` normally. PR1 does not expose that legacy surface as `backend.routes`; the backend route domain is deferred until a future PR has a concrete route/provider workflow and privilege review.
+Backend route metadata should support a declared capability domain. A generic `backend.routes` domain is deferred until a future PR has a concrete route/provider workflow and privilege review.

 Plugins that call `context["register_library_provider"](...)` are attributed to the loading plugin id in `/api/library/providers` as `owner_plugin_id`. The browser library capability module at [static/capabilities/library.js](../static/capabilities/library.js) owns the `library` domain as a `provider-coordinator`: it refreshes `/api/library/providers`, registers the built-in `local` provider as `core.library.local`, and registers plugin-backed providers under their `owner_plugin_id` when one is known. Provider manifests should still declare the `library` capability so diagnostics and the bundled inspector can show intended relationships before the backend route code runs.

-Route-only external plugins that participate in library workflows without registering a browsable provider should declare requester/observer intent instead of provider ownership when they adopt this contract in their own repositories. This PR documents the generic shape only: such plugins use `library` requester/observer `requests` and `observes` declarations and do not appear as providers, owners, or separate `backend.routes` domains.
+Route-only external plugins that participate in library workflows without registering a browsable provider declare requester/observer intent instead of provider ownership when they adopt this contract in their own repositories. This PR documents the generic shape only: such plugins use `library` requester/observer `requests` and `observes` declarations and do not appear as providers, owners, or separate `backend.routes` domains.

 ```json
 {
@@ -69,21 +74,19 @@ Capability declarations may include a short `description`. The bundled Capabilit

 ## Audio Graph/Session Domains

-The audio graph/session slice promotes four player-audio domains into the runtime graph: `audio-mix`, `audio-input`, `audio-monitoring`, and `stems`. The browser module at [static/capabilities/audio-session.js](../static/capabilities/audio-session.js) owns the active session boundary, contributes diagnostics under `slopsmith.audio_session.diagnostics.v1`, and records compatibility bridge hits for legacy audio surfaces.
+The audio graph/session slice promotes four player-audio domains into the runtime graph: `audio-mix`, `audio-input`, `audio-monitoring`, and `stems`. The browser module at [static/capabilities/audio-session.js](../static/capabilities/audio-session.js) owns the active session boundary, contributes diagnostics under `slopsmith.audio_session.diagnostics.v1`, and records compatibility bridge hits for older audio surfaces.

-`audio-mix`, `audio-input`, and `audio-monitoring` are core-owned provider-coordinator domains. They expose bounded inspect/register/start/stop style commands, redaction-safe diagnostics, and bridge accounting for legacy fader, analyser, input, and monitoring handshakes.
+`audio-mix`, `audio-input`, and `audio-monitoring` are core-owned provider-coordinator domains. They expose bounded inspect/register/start/stop style commands, redaction-safe diagnostics, and bridge accounting for older fader, analyser, input, and monitoring handshakes.

 For `audio-mix`, native fader providers register mix participants with stable `participantId`, `kind`, `sourceMode`, optional `logicalFaderKey`, and `fader` metadata. The public command surface is `inspect`, `list-faders`, `get-fader-value`, `set-fader-value`, `inspect-route`, `inspect-analyser`, `register-participant`, and `unregister-participant`; provider operations are `fader.get-value`, `fader.set-value`, `route.get-current`, and `analyser.get-summary`. Providers own persistence for plugin faders and must return committed values from set operations so the player mixer can display the value that actually applied.

-Legacy `window.slopsmith.audio.registerFader(...)` remains supported as an audio-mix compatibility bridge. The bridge registers a compatibility-backed participant, wraps legacy `getValue`/`setValue` callbacks as provider operations, and preserves `window.slopsmith.audio.getFaders()` for external callers. If a native participant and a legacy fader share the same logical fader key, the native participant owns the visible control; the legacy participant is retained for diagnostics with `supersededBy` and an `overshadowed` bridge hit. Removal gates for the bridge are: native providers cover bundled mixer integrations, diagnostics show no unexpected legacy hits in normal playback, and repeated plugin hydration does not create duplicate faders.
-
 Audio-mix diagnostics live under `slopsmith.audio_session.diagnostics.v1`. The `audio-mix` domain snapshot includes session state, participants, visible fader summaries, required participant-kind coverage, route summary, analyser summary, bridge hits, and bounded recent outcomes. Fader outcomes include operation name, participant id, fader id, status such as `committed`, `normalized`, `unavailable`, or `timeout`, and a bounded reason. Diagnostics must not include raw audio buffers, FFT arrays, device labels, stable hardware identifiers, secrets, or unredacted local paths; route/analyser payloads are summaries only.

 For `audio-input`, native providers register source summaries with `sourceId`, `providerId`, `logicalSourceKey`, `kind`, redaction-safe label/pseudonym, `availability`, `channelSummary`, `sourceMode`, and provider operations. The public command surface is `inspect`, `list-sources`, `register-source`, `unregister-source`, `select-source`, `open-source`, and `close-source`; provider operations are `source.enumerate`, `source.describe`, `source.open`, and `source.close`. `inspect`, `list-sources`, and `select-source` are prompt-free and never open live input or call enumeration. `source.enumerate` runs only when explicitly requested by provider/user discovery. `open-source` is the permission boundary: it routes to `source.open`, attributes the requester, checks the selected source and requested channel shape, and records `handled`, `denied`, `degraded`, `failed`, `no-owner`, `no-handler`, `unsupported-command`, or `incompatible-version` outcomes.

 Selected input is persisted by `logicalSourceKey` when browser storage is available. If storage is unavailable, the in-memory selection remains usable for the current session and diagnostics report the storage status. Start/stop/song switches preserve selected input independently of playback transport while clearing live open sessions. Compatible requesters share one open session per logical source and channel shape; requester references are released via `close-source`, and the provider receives `source.close` only after the last requester releases.

-Compatibility-backed input sources should record `sourceMode: "compatibility"` plus `compatibilitySource` and, when applicable, an `audio-input.legacy-source` bridge hit. If a native provider and a compatibility-backed source share the same logical source key, the native source owns the visible source list and the compatibility source is retained in diagnostics with `supersededBy`. Removal gates for input bridges are: native providers cover bundled source discovery/open flows, diagnostics show no unexpected compatibility hits in normal playback, denied/unavailable/failure outcomes are distinguishable, repeated hydration does not create duplicate sources, and support snapshots contain no raw device labels, hardware ids, paths, secrets, live handles, buffers, samples, or waveform data.
+Compatibility-backed input sources are retained for diagnostics only when a native provider supersedes the same logical source key. Removal gates for input bridges are: native providers cover bundled source discovery/open flows, diagnostics show no unexpected compatibility hits in normal playback, denied/unavailable/failure outcomes are distinguishable, repeated hydration does not create duplicate sources, and support snapshots contain no raw device labels, hardware ids, paths, secrets, live handles, buffers, samples, or waveform data.

 For `audio-monitoring`, native providers register monitoring summaries with `providerId`, `logicalMonitoringKey`, redaction-safe label/pseudonym, `availability`, `sourceMode`, provider operations, `directMonitor`, and `latencySummary`. The public command surface is `inspect`, `list-providers`, `register-provider`, `unregister-provider`, `select-provider`, `start`, `stop`, and `set-direct-monitor`; provider operations are `monitoring.start`, `monitoring.stop`, `monitoring.status`, and `monitoring.set-direct-monitor`. `inspect`, `list-providers`, `select-provider`, and `monitoring.status` are prompt-free and must not open audio input or start monitoring.

@@ -93,25 +96,11 @@ Monitoring sessions are keyed by provider, selected source, required channel sha

 Direct-monitor state is user-authoritative. `set-direct-monitor` updates the user's/default preference and applies provider control to active sessions only when the provider supports it. Requester `directMonitorRequirement` values are advisory constraints: when they conflict with the user's preference or provider support, the requester/session is marked degraded or unsupported, but the stored user/default preference is not changed.

-Compatibility-backed monitoring providers should record `sourceMode: "compatibility"` plus `compatibilitySource` (which becomes the bridge id, defaulting to `audio-monitoring.legacy-provider` when unset) and, when applicable, the `audio-monitoring.audio-barrier` startup-barrier bridge hit. If a native provider and compatibility-backed provider share a logical monitoring key, the native provider owns the visible provider list and the compatibility provider is retained in diagnostics with `supersededBy`. Removal gates for monitoring bridges are: native providers cover bundled start/stop/status/direct-monitor flows, normal playback shows no unexpected legacy hits, background requesters cannot silently start live monitoring, repeated hydration does not duplicate providers or sessions, and support snapshots contain no raw device labels, hardware ids, paths, secrets, live handles, buffers, samples, waveform data, recordings, or provider-private payloads.
+Compatibility-backed monitoring providers are retained for diagnostics only when a native provider supersedes the same logical monitoring key. Removal gates for monitoring bridges are: native providers cover bundled start/stop/status/direct-monitor flows, normal playback shows no unexpected compatibility hits, background requesters cannot silently start live monitoring, repeated hydration does not duplicate providers or sessions, and support snapshots contain no raw device labels, hardware ids, paths, secrets, live handles, buffers, samples, waveform data, recordings, or provider-private payloads.

 `stems` is different: `core.audio.session` is a coordinator, not the semantic owner of stem playback. The Stems plugin, or another active stem provider, remains the provider/owner of actual stem state, mute/restore mechanics, and per-song availability. The session coordinator records the active provider via `registerStemOwner(...)`, brokers claim/override/orphan diagnostics, and returns `no-owner` when no stem provider is available.

-New bundled audio code should use the session host or native capability dispatch instead of adding new globals, private stem-state reads, direct analyser ownership, or plugin-specific handshakes. Existing legacy paths remain supported through named compatibility bridges until their migration notes and removal gates are satisfied.
-
-## Audio Effects Domain
-
-The audio-effects slice promotes `audio-effects` as a core-owned provider-coordinator domain implemented by [static/capabilities/audio-effects.js](../static/capabilities/audio-effects.js). The host owns provider selection, compatible executor selection, route state, fallback accounting, redaction-safe diagnostics, and the constrained chain-plan schema. Providers do not call executors. Provider code proposes plans and, for execution requests, returns a provider-private trusted asset map to the host; the host immediately hands that private request to a compatible executor such as trusted Desktop native audio or NAM Tone's browser/WASM executor.
-
-The public command surface is `inspect`, `list-providers`, `list-executors`, `register-provider`, `unregister-provider`, `register-executor`, `unregister-executor`, `select-chain`, `resolve-plan`, `load-plan`, `inspect-route`, `list-mappings`, `upsert-mapping`, `delete-mapping`, `activate-mapping`, `clear-active-mapping`, `bypass`, `restore`, `fallback`, `activate-segment`, `set-stage-bypass`, `set-stage-parameter`, and `record-bridge-hit`. Provider operations are `chain.resolve`, `chain.inspect`, `mapping.list`, `mapping.upsert`, `mapping.delete`, `mapping.activate`, `mapping.clear-active`, `segment.activate`, `stage.set-bypass`, `stage.set-parameter`, `route.bypass`, and `route.restore`; executor operations are `loadChainPlan`, `activateSegment`, `setStageBypass`, and `setStageParameter`. Fresh chain selection and route bypass/restore require `authorization: "user-action"` or `authorization: "restore-selection"`; physical loading through `load-plan` requires `authorization: "user-action"`, `authorization: "restore-selection"`, or `authorization: "playback-session"`. Background requesters may inspect the current route and resolve an already selected compatible provider.
-
-Core also owns the durable public mapping index at `/api/audio-effects/mappings`. A mapping answers "for this song/tone, this provider has an addressable effect plan"; it does not contain the provider's preset or chain data. Rows are keyed by `song_key + tone_key + provider_id`, carry an opaque `provider_ref`, and may be marked as the active mapping for that song/tone. Providers CRUD their own rows through the audio-effects host and resolve `provider_ref` inside their own storage when `chain.resolve` runs. This lets NAM Tone and Rig Builder coexist for the same song/tone while core owns arbitration and fallback order. `song_key` should be the playback domain's redaction-safe settings key when available; `filename` is optional legacy/debug context for migration and display.
-
-Providers register stable `providerId`, `pluginId`, `routeKey`, priority, availability, source mode, operations, and operation handlers. Executors register stable `executorId`, `pluginId`, `routeKey`, priority, availability, source mode, supported provider ids, supported stage kinds, optional maximum stage count, operations, and handlers. The host chooses the highest-priority enabled provider for a route unless the caller requests a specific provider, then chooses the highest-priority compatible executor for that provider and resolved plan. Compatibility means both provider-compatible and plan-compatible: a browser/WASM NAM executor can advertise `providerIds: ["nam-tone"]`, `supportedKinds: ["nam", "ir"]`, and `maxStages: 2`, so it will not be asked to execute a Rig Builder VST/full-chain plan. If a selected provider has no compatible executor and the caller supplies a fallback provider, the host may fall back to that provider; if the caller explicitly requested the original provider, the host reports `unavailable` instead of silently changing providers. The initial default route is `desktop-main`, matching the desktop native executor path planned for full-chain NAM/IR/VST playback while still allowing browser executors for non-Desktop runtimes.
-
-`chain.resolve` returns schema `slopsmith.audio_effects.chain_plan.v1`. A valid plan includes `planId`, `routeKey`, `providerId`, `stages`, optional `segments`, and optional redaction-safe summaries. Each stage exposes only stable opaque `stageId`, `kind` (`nam`, `ir`, `vst`, `utility`, or `bypass`), `role` (`pre-pedal`, `amp`, `cab`, `rack`, `master-pre`, etc.), opaque `assetRef`, optional opaque `stateRef`, bypass state, gain summary, and safe summary metadata. Raw file paths, URLs, model filenames, IR filenames, VST state blobs, native preset JSON, callbacks, handles, DOM nodes, audio buffers, samples, and waveform data are rejected or omitted.
-
-Diagnostics live under `slopsmith.audio_effects.diagnostics.v1`. The snapshot includes provider summaries, executor summaries, route summaries, bridge hits, bounded recent outcomes, limits, and redaction notes. It intentionally omits full chain plans, stage asset references, provider-private mapping payloads, raw filenames, and song keys; diagnostics should explain which provider/executor/route failed without leaking local library structure or licensed asset names. Legacy NAM Tone/Rig Builder fetch interception, direct Desktop `loadPreset` calls, legacy tone controls, old `nam_tone.db` `tone_mappings` access, and MIDI/external effect handoffs are attributed through `audio-effects.legacy-nam-routing`, `audio-effects.legacy-native-load`, `audio-effects.legacy-tone-controls`, `audio-effects.legacy-tone-db`, and `audio-effects.legacy-midi-amp` bridge records while providers migrate.
+New bundled audio code should use the session host or native capability dispatch instead of adding new globals, private stem-state reads, direct analyser ownership, or plugin-specific handshakes.

 ## Playback Control Plane

@@ -119,39 +108,7 @@ The playback slice promotes `playback` as a core-owned command domain implemente

 `static/app.js` remains the transport data plane. It registers a private playback adapter that can start songs, pause/resume/stop, seek, and manage loops, but the capability snapshot never exposes the `<audio>` element, JUCE player object, raw audio buffers, native route handles, samples, waveforms, recordings, local file paths, or URL payloads. Exported diagnostics use pseudonymous `target-*` ids for arrangement-scoped identity and hashed `settings-*` keys for per-song plugin settings; the local Capability Inspector may show visible title, artist, and arrangement labels for the active song.

-Legacy playback surfaces remain supported during migration and are attributed through bridges such as `playback.window-play-song`, `playback.song-events`, `playback.window-slopsmith-transport`, `playback.loop-api`, and native route handoff records. Fresh audible `start` commands require `authorization: "user-action"`; background requesters may inspect or control an existing session, but user-priority pause/stop decisions block lower-priority automation until a user action resumes or starts a new session.
-
-## Progression Domain
-
-The progression slice (spec 010) promotes `progression` as a core-owned command domain implemented by [static/v3/progression-core.js](../static/v3/progression-core.js). Core owns the player's mastery rank (onboarding calibration + instrument-path levels), the challenge/quest engine, the Decibels wallet, and the cosmetics shop; all definitions are bundled content under `data/progression/` so new paths, levels, challenges, quests, and shop items are JSON edits, never code.
-
-The public command surface is `inspect`, `record-event`, `list-shop`, `buy-item`, and `equip-item`. `record-event` accepts only whitelisted externally-postable event types (`minigame_run` in v1); `song_completed` is server-derived inside `/api/stats` so scored-session authority stays in one place and is denied at this surface. `buy-item` and `equip-item` require `authorization: "user-action"`. Backend plugins use the symmetric plugin-context hook `record_progression_event` (the minigames hub reports runs through it), which trusts backend code and skips the HTTP whitelist.
-
-The domain emits `challenge-completed`, `quest-completed`, `path-level-up`, `rank-changed`, `db-changed`, `calibration-completed`, and `cosmetic-equipped` on the capability surface, mirrored as `progression:*` events on `window.slopsmith` for non-capability consumers. Diagnostics live under `slopsmith.progression.diag.v1` and contain content-load warnings, rank/path-level/quest counts, and wallet totals only — no song filenames or display names.
-
-Decibels are earned exclusively by playing (songs, minigame runs, quest rewards); there is no real-money acquisition path and none may be added. The wallet tracks spend separately from the monotonic lifetime-earned total, so per-source XP resets and `db_earned` goals stay correct. A deferred release slice adds a `contributor` role so plugins can ship their own challenge/quest content (e.g. a drums plugin contributing drums challenges); content stays core-bundled until then.
-
-## Visualization Domain
-
-The visualization slice (cap:6) promotes `visualization` as a core-owned provider-coordinator implemented by [static/capabilities/visualization.js](../static/capabilities/visualization.js). Viz plugins are providers of the highway renderer surface; the core picker/auto-match machinery in `static/app.js` stays the selection workflow and attributes every renderer change into the domain.
-
-The public command surface is `inspect`, `list-providers`, `select-renderer`, and `clear-renderer`. Selection delegates to the existing picker (`setViz`) so localStorage persistence, WebGL2 gating, and fallback semantics have exactly one implementation. The domain emits `providers-refreshed`, `renderer-changed` (with a `source` of `auto-match`, `user-select`, `fallback`, or `command:<requester>`), `renderer-ready`, and `renderer-failed`.
-
-Provider discovery is still the legacy surface — `type: "visualization"` manifests populate the picker and `window.slopsmithViz_*` factory globals carry the renderer contract — and both are registered as compatibility shims (`visualization:type-visualization-manifest`, `visualization:window.slopsmithViz_*`) with hit accounting, so the Inspector shows exactly how much of the domain still rides the bridge. Plugins migrate by declaring a `visualization` provider capability in their manifests; the renderer factory contract (`init`/`draw`/`resize`/`destroy`, `contextType`, `matchesArrangement`) is unchanged.
-
-**Per-instance provider settings (#849).** A provider may declare a `settings` array on its `visualization` capability — generic control descriptors (`{ key, label, type: "toggle" | "range" | "select", default, min/max/step, options }`) the capability-pipelines schema validates on *any* domain (the field lives on the shared `capabilityDeclaration`, not a visualization-only spot — see `docs/plugin-manifest.schema.json`). Descriptors flow through the **generic participant model**: the backend validates them for `/api/plugins` (`plugins/__init__.py`), `static/capabilities.js` normalizes + preserves them on the registered participant (so generic `inspect('visualization')` carries them), and the visualization owner reads them back from the participant by id — no app.js/picker side channel. They surface in the `list-providers` snapshot (each provider's `settings`, deep-frozen) plus a `provider_policy.hasSettings` flag in diagnostics, so a consuming host — splitscreen's per-panel control popover — can render the controls generically without per-plugin hardcoding. The visualization domain's **apply contract**: a provider that declares `settings` MUST implement `applySetting(key, value)` on its renderer instance (the host calls it on the specific per-panel instance, which is inherently per-panel — no canvas→panel resolution, no shared global keys); `getSetting(key)` is optional (the host falls back to the declared `default`). The host owns persistence. **This core slice lands the declarative surface + participant plumbing only** — no bundled provider declares `settings` yet (`highway_3d` still ships the legacy `factory.panelControls` static). The `highway_3d` migration and the splitscreen generic consumer are the remaining #849 follow-ups.
-
-Diagnostics live under `slopsmith.visualization_capability.v1` and contain provider ids/labels/context types, the active renderer id and its selection source, the last auto-match outcome (resolved id + whether any predicate claimed the song), and the last failure (provider id + reason) — never song filenames, titles, or arrangement names. Per-panel selection (splitscreen #90) and per-panel provider settings (#849) are tracked follow-ups; the domain currently models the primary highway surface.
-
-## Note-Detection Domain
-
-The note-detection slice (spec 009, issues #727/#728) promotes `note-detection` as a core-owned provider-coordinator implemented by [static/capabilities/note-detection.js](../static/capabilities/note-detection.js). Doctrine per [specs/009-note-detection-domain/spec.md](../specs/009-note-detection-domain/spec.md): the domain exposes detection PRIMITIVES through requester-owned, context-scoped bindings — a monophonic pitch estimate and a polyphonic "is this note set ringing now?" verification — and consumers own all judgment semantics (hit windows, streaks, accuracy, tiers). Hit/miss/verdict results flow through the domain as observability events, never as domain-owned scoring.
-
-The public command surface is `inspect`, `register-provider`, `unregister-provider`, `open-binding`, `close-binding`, `set-target`, and `clear-target`. Providers declare a kind — `midi` (a digital instrument producing exact verdicts, e.g. the keys highway's Web-MIDI input), `engine` (the desktop JUCE verifier), or `js` (the browser harmonic-comb / YIN fallback) — and the primitives they serve (`pitch.estimate`, `verify.target`). Each binding carries its requester's own redacted context summary (arrangement kind, string count, capo, MIDI range), independent of whatever song the host highway has loaded; concurrent bindings never perturb one another (spec 009 FR-003). With no provider registered, `open-binding` reports `unavailable` — consumers degrade, never block.
-
-The legacy chart-coupled surface — `highway.setNoteStateProvider(fn)`, the single-global-detector path spec 009 retires — keeps working unchanged and is wrapped for compatibility-shim hit accounting (`note-detection:highway.setNoteStateProvider`). Migrating the chart `note_detect` consumer, Step Mode verify, minigames YIN scoring, and the `setVerifyTarget` bridge onto real bindings — and wiring per-binding tuning contexts into the engine verifier — is the remainder of the spec-009 slice and lands behind the Spec 003 migration gate.
-
-Diagnostics live under `slopsmith.note_detection_capability.v1` and contain provider ids/labels/kinds, binding summaries (requester, provider, redacted context, target size), availability, and the last bounded outcome (event, binding, provider, MIDI number, hit flag) — never raw audio buffers, sample data, device labels, or song identity.
+Fresh audible `start` commands require `authorization: "user-action"`; background requesters may inspect or control an existing session, but user-priority pause/stop decisions block lower-priority automation until a user action resumes or starts a new session.

 ## Capability Roles

@@ -180,9 +137,9 @@ Core domains include review metadata in diagnostics:
 - `active`: wired to current Slopsmith behavior and expected to work as an integration point.
 - `diagnostic`: support/inspection-only runtime surfaces.

-PR1 includes only the delivered domains listed in [capability-roadmap.md](capability-roadmap.md): `pipeline`, `diagnostics`, and `library`. The follow-up audio graph/session slice promotes `audio-mix`, `audio-input`, `audio-monitoring`, and a coordinated `stems` surface. The playback slice promotes `playback` as an active transport control plane. The audio-effects slice promotes provider-selected effect-chain planning while leaving physical processor loading to compatible executors such as trusted Desktop native audio or a browser/WASM executor. The visualization slice promotes `visualization` as the highway renderer provider-coordinator, and the note-detection slice (spec 009) promotes `note-detection` as the detection-binding control plane. Backend routes, app UI, settings, and other hardware-facing domains remain documented in the roadmap and safety matrix until their own host workflow/provider slice exists.
+PR1 includes only the delivered domains listed in [capability-roadmap.md](capability-roadmap.md): `pipeline`, `diagnostics`, and `library`. The follow-up audio graph/session slice promotes `audio-mix`, `audio-input`, `audio-monitoring`, and a coordinated `stems` surface. The playback slice promotes `playback` as an active transport control plane. Backend routes, app UI, settings, visualization, note-detection, and other hardware-facing domains remain documented in the roadmap and safety matrix until their own host workflow/provider slice exists.

-Capability metadata is versioned by the `capability-pipelines.v1` standard. Invalid roles, commands, operations, requests, observes, emits, events, owner kinds, compatibility modes, ownership policies, safety classes, or version fields are excluded from the capability graph and surfaced through `capability_validation_warnings`; legacy plugin fields continue to load through their existing app paths. Plugins that declare a future `capability-pipelines` version are reported through `capability_unsupported_versions` and their runtime handlers are marked incompatible.
+Capability metadata is versioned by the `capability-pipelines.v1` standard. Invalid roles, commands, operations, requests, observes, emits, events, owner kinds, compatibility modes, ownership policies, safety classes, or version fields are excluded from the capability graph and surfaced through `capability_validation_warnings`. Plugins that declare a future `capability-pipelines` version are reported through `capability_unsupported_versions` and their runtime handlers are marked incompatible.

 `diagnostics` and `pipeline` are adjacent support domains. `diagnostics` is the read-only snapshot/export surface: `snapshot` returns the redaction-safe state used by support bundles and the Capability Inspector. `pipeline` is the graph operations surface: `inspect`, `validate`, and `participant.set-enabled` operate on the capability graph itself and emit graph lifecycle events such as `resolved`, `runtime.validated`, and `participant.state-changed`.

@@ -217,7 +174,7 @@ Owner participants use a `kind` that describes how the domain is coordinated:
 - `diagnostic`: read-only support and inspector surfaces.
 - `privileged`: command execution needs an explicit enforcement plan before shipping.

-Legacy `ownership` remains accepted in manifests for compatibility and diagnostics, but new domains should prefer `kind` plus participant roles. Ownership is derived for core owners where possible: `provider-coordinator` behaves like a multi-provider domain, diagnostics are diagnostic-only, privileged owners are privileged, and command/event owners are exclusive by default.
+New domains should prefer `kind` plus participant roles. Ownership is derived for core owners where possible: `provider-coordinator` behaves like a multi-provider domain, diagnostics are diagnostic-only, privileged owners are privileged, and command/event owners are exclusive by default.

 The compatibility ownership vocabulary remains:

@@ -232,9 +189,9 @@ Dispatch results use explicit outcomes: `handled`, `transformed`, `denied`, `fai

 ## Deferred Core Adapters

-UI placement and settings contributions are real Slopsmith surfaces, but they are not PR1 capability contracts (visualization is active as of the cap:6 slice; note-detection as of the spec-009 slice). Audio mixer/session domains are active as of the audio graph/session slice, playback is active as of the playback control-plane slice, and audio-effects is active as a provider/route/chain-plan coordinator; plugins should keep using current documented APIs for remaining areas until the corresponding domain PR ships the host workflow, command/event contract, compatibility shims, diagnostics fields, and tests.
+UI placement, settings contributions, visualization, and note-detection are real Slopsmith surfaces, but they are not PR1 capability contracts. Audio mixer/session domains are active as of the audio graph/session slice, and playback is active as of the playback control-plane slice. For remaining areas, document the capability gap and avoid adding new private integration surfaces until the corresponding domain PR ships the host workflow, command/event contract, diagnostics fields, and tests.

-The library provider workflow is the PR1 core adapter and is implemented natively as the `library` capability module. Provider refresh, selection, and sync run through `library` owner commands; backend provider registration remains the way providers enter the library registry, and the browser module turns that registry into provider participants. The app event bus continues to dispatch local `window.slopsmith` events for legacy listeners; playback now mirrors song transport, route, seek, and loop lifecycle into `playback`, and visualization attributes renderer selection/failure, while navigation, note, and route-only surfaces remain outside capability domains until their own slices land.
+The library provider workflow is the PR1 core adapter and is implemented natively as the `library` capability module. Provider refresh, selection, and sync run through `library` owner commands; backend provider registration remains the way providers enter the library registry, and the browser module turns that registry into provider participants. Playback mirrors song transport, route, seek, and loop lifecycle into `playback`, while navigation, note, visualization, route-only, and highway rendering surfaces remain outside capability domains until their own slices land.

 The direct `window.highway` object remains the renderer data plane. Per-frame reads such as notes, chords, beats, and renderer hooks should not be moved behind asynchronous capability commands until there is a dedicated chart/render facade.

@@ -242,13 +199,13 @@ The direct `window.highway` object remains the renderer data plane. Per-frame re

 Large management surfaces should prefer plugin-owned UI over crowding normal Settings. First-party management plugins can contribute screens and settings panels while core keeps shared services and diagnostics contracts centralized.

-The bundled Capability Inspector plugin is the support surface for the current graph. It reads `window.slopsmith.capabilities.snapshotDiagnostics()`, filters by domain, and summarizes manifest participants, runtime participants, conflicts, unsupported versions, safety classes, expected legacy event surfaces, and compatibility shim hits without rendering raw runtime objects. Domains are grouped in review order: application/library, player/audio runtime, plugin-defined surfaces, then capability runtime. In the all-domains view, each domain starts collapsed with a domain-specific icon plus compact summary badges for participant-lane count, endpoint count, observed links, shimmed links, and status; badge labels live in tooltips/ARIA labels so the header stays scannable. Clicking the domain label expands or collapses the domain, opening the same graph view used by the single-domain filter. The graph places owner details and right-aligned command/event groups on the left, with short owner descriptions bottom-aligned as the final part of that pane. Participant usage is grouped the same way on the right, with observed or shimmed links between border-aligned endpoint ports. In multi-provider domains, links to provider participants use provider-family colors: purple for owner-to-provider command delegation and a lighter violet for provider events. Provider participants, including `library` sources, stay on the right lane and show a provider icon in their header. Headers show role-aware core/non-core origin badges such as Core owner, Core provider, or Non-core participant; owner headers place the origin badge directly after the owner icon, and the built-in local library provider is marked as core-origin. Observer and requester roles are implied by the command/event links rather than separate header badges. Participant cards are shown only when the plugin or runtime source has visible command or event usage for the current graph filter; domains with no such usage show zero participants, and attribution-only shims with no matching endpoint stay out of the lane. Command and event groups can collapse; when collapsed, all links for that side and group converge on the single group port. Hovering a participant, endpoint, or command/event group emphasizes the matching links and dims unrelated links; owner-side labels outside the current focus de-emphasize so the active source endpoints are easy to track. Expanded domain graphs progressively enhance to Cytoscape.js overlays that route bezier links between measured DOM endpoint ports, while keeping the HTML lanes as the fallback and readable data surface. Its Plugins-menu entry is hidden by default; enable **Capability Inspector → Show in Plugins menu** from Settings when reviewing or debugging capability behavior.
+The bundled Capability Inspector plugin is the support surface for the current graph. It reads `window.slopsmith.capabilities.snapshotDiagnostics()`, filters by domain, and summarizes manifest participants, runtime participants, conflicts, unsupported versions, safety classes, expected compatibility event surfaces, and compatibility shim hits without rendering raw runtime objects. Domains are grouped in review order: application/library, player/audio runtime, plugin-defined surfaces, then capability runtime. In the all-domains view, each domain starts collapsed with a domain-specific icon plus compact summary badges for participant-lane count, endpoint count, observed links, shimmed links, and status; badge labels live in tooltips/ARIA labels so the header stays scannable. Clicking the domain label expands or collapses the domain, opening the same graph view used by the single-domain filter. The graph places owner details and right-aligned command/event groups on the left, with short owner descriptions bottom-aligned as the final part of that pane. Participant usage is grouped the same way on the right, with observed or shimmed links between border-aligned endpoint ports. In multi-provider domains, links to provider participants use provider-family colors: purple for owner-to-provider command delegation and a lighter violet for provider events. Provider participants, including `library` sources, stay on the right lane and show a provider icon in their header. Headers show role-aware core/non-core origin badges such as Core owner, Core provider, or Non-core participant; owner headers place the origin badge directly after the owner icon, and the built-in local library provider is marked as core-origin. Observer and requester roles are implied by the command/event links rather than separate header badges. Participant cards are shown only when the plugin or runtime source has visible command or event usage for the current graph filter; domains with no such usage show zero participants, and attribution-only shims with no matching endpoint stay out of the lane. Command and event groups can collapse; when collapsed, all links for that side and group converge on the single group port. Hovering a participant, endpoint, or command/event group emphasizes the matching links and dims unrelated links; owner-side labels outside the current focus de-emphasize so the active source endpoints are easy to track. Expanded domain graphs progressively enhance to Cytoscape.js overlays that route bezier links between measured DOM endpoint ports, while keeping the HTML lanes as the fallback and readable data surface. Its Plugins-menu entry is hidden by default; enable **Capability Inspector → Show in Plugins menu** from Settings when reviewing or debugging capability behavior.

 ## Diagnostics Contract

 Capability diagnostics use schema `slopsmith.capabilities.diagnostics.v1`. Snapshots are redaction-safe and capped at 64 KB by trimming older `recentDecisions` first while preserving current participants, active or orphaned claims, conflicts, domain review metadata, shim summaries, safety notes, and unsupported-version reports. Server diagnostics bundles include plugin manifest capability metadata, validation warnings, unsupported-version metadata, and compatibility shim summaries.

-Compatibility shim entries include `shimId`, `source`, `capability`, `legacySurface`, `status`, `reason`, and optional hit fields. A shim with `hitCount > 0` means legacy behavior was observed, not merely declared. The `library` domain no longer uses compatibility shims for provider registration or source selection; provider attribution comes from `owner_plugin_id` and runtime provider participants. Future domains should add expected shim entries only in the PR that implements their actual legacy bridge.
+Compatibility shim entries include `shimId`, `source`, `capability`, `legacySurface`, `status`, `reason`, and optional hit fields. A shim with `hitCount > 0` means compatibility behavior was observed, not merely declared. The `library` domain no longer uses compatibility shims for provider registration or source selection; provider attribution comes from `owner_plugin_id` and runtime provider participants. Future domains should add expected shim entries only in the PR that implements their actual compatibility bridge.

 ## Expected Future Domains

@@ -260,20 +217,31 @@ Release slices should stay reviewable. The domain-level roadmap, PR1 domain set,

 Future privileged domains must state user value, included and excluded commands, safety class, diagnostics fields, failure recovery, and tests proving disabled or incompatible participants cannot execute handlers before implementation begins.

-## Rehydration Pattern
+## Runtime Idempotency Pattern

-Plugins that wrap shared functions such as `window.playSong` or `window.showScreen` should store wrapper state on a stable `window.__slopsmith...Hooks` object. Re-running the script should replace the implementation object and return before installing another wrapper.
+Plugins that declare `plugin-runtime-idempotent.v1` must tolerate repeated script hydration without duplicating participants, listeners, timers, DOM roots, jobs, media nodes, or diagnostics contributors. Use stable ids and replace the current implementation behind the participant instead of registering a second copy.

 ```js
-const hookState = window.__slopsmithMyPluginHooks || (window.__slopsmithMyPluginHooks = {});
-hookState.impl = { afterPlaySong(filename) { /* current implementation */ } };
-if (hookState.installed) return;
-hookState.installed = true;
-hookState.basePlaySong = window.playSong;
-window.playSong = async function(filename, arrangement) {
-  await hookState.basePlaySong.call(this, filename, arrangement);
-  hookState.impl?.afterPlaySong?.(filename, arrangement);
+const runtime = window.__slopsmithMyPluginRuntime || (window.__slopsmithMyPluginRuntime = {});
+runtime.impl = {
+  async inspect() {
+    return { ready: true };
+  },
 };
+
+if (!runtime.registered) {
+  runtime.registered = true;
+  window.slopsmith.capabilities.registerParticipant('my_plugin.runtime', {
+    'example.plugin-domain': {
+      roles: ['provider'],
+      commands: ['inspect'],
+      handlers: {
+        inspect: () => runtime.impl.inspect(),
+      },
+      runtime: true,
+    },
+  });
+}
 ```

 ## Validation Commands
@@ -100,7 +100,7 @@ A plugin that registers a remote client or generated library source declares its

 ## Library Requester And Observer

-A route-only wrapper that uses the library capability without registering a browsable provider should declare requester/observer intent instead of provider ownership. This is a generic manifest shape for external plugins to adopt in their own repositories; it does not make the wrapper part of this PR's delivered domain set.
+A route-only wrapper that uses the library capability without registering a browsable provider declares requester/observer intent instead of provider ownership. This is a generic manifest shape for external plugins to adopt in their own repositories; it does not make the wrapper part of this PR's delivered domain set.

 ```json
 {
@@ -147,121 +147,9 @@ Existing plugins can keep using `window.slopsmith.audio.registerFader(spec)` whi

 Native audio-mix fader providers should register a stable participant id and fader id, return the committed value from every set operation, and settle get/set operations within two seconds. The player mixer displays the committed value rather than the raw requested value. If the fader is temporarily unavailable, keep the participant registered with unavailable/disabled state so the mixer can render a disabled control and diagnostics can explain why it cannot be changed.

-During migration, a plugin may still call `window.slopsmith.audio.registerFader(spec)`. Core maps that legacy fader into a compatibility-backed audio-mix participant and records bridge hits. If a native participant and a legacy fader represent the same logical source, the native participant owns the visible control and the legacy path is reported as compatibility-backed/overshadowed.
-
-## Audio Effects Provider
-
-Plugins that can provide guitar/bass processing chains should declare `audio-effects` as a provider and register at runtime with `window.slopsmith.audioEffects.registerProvider(...)`. The provider returns opaque chain plans; it must not expose local filenames, URLs, native preset JSON, VST state blobs, or raw handles through diagnostics or public route state.
-
-```json
-{
-  "id": "rig_builder",
-  "name": "Rig Builder",
-  "standards": ["capability-pipelines.v1", "plugin-runtime-idempotent.v1"],
-  "capabilities": {
-    "audio-effects": {
-      "roles": ["provider"],
-      "operations": ["chain.resolve", "chain.inspect", "segment.activate", "stage.set-bypass", "stage.set-parameter"],
-      "events": ["provider-registered", "route-selected", "plan-resolved", "changed", "fallback", "bridge-hit"],
-      "mode": "active",
-      "compatibility": "shim-allowed",
-      "safety": "sensitive",
-      "version": 1
-    }
-  }
-}
-```
-
-```js
-const effects = window.slopsmith && window.slopsmith.audioEffects;
-effects.registerProvider({
-  providerId: 'rig-builder',
-  pluginId: 'rig_builder',
-  routeKey: 'desktop-main',
-  priority: 40,
-  operations: ['chain.resolve', 'segment.activate', 'stage.set-bypass', 'stage.set-parameter'],
-  operationHandlers: {
-    'chain.resolve': request => ({
-      outcome: 'handled',
-      plan: {
-        schema: 'slopsmith.audio_effects.chain_plan.v1',
-        planId: 'song-tone-plan',
-        routeKey: request.routeKey,
-        providerId: 'rig-builder',
-        stages: [
-          { stageId: 'amp', kind: 'nam', role: 'amp', assetRef: 'rig-builder:asset:amp-main' },
-          { stageId: 'cab', kind: 'ir', role: 'cab', assetRef: 'rig-builder:asset:cab-main' }
-        ],
-        segments: [{ segmentId: 'base', stageIds: ['amp', 'cab'] }],
-        summary: { stageCount: 2 }
-      }
-    })
-  }
-});
-```
-
-User-facing controls should dispatch through the domain instead of mutating another plugin's private state:
-
-```js
-await window.slopsmith.capabilities.dispatch({
-  capability: 'audio-effects',
-  command: 'select-chain',
-  source: 'rig_builder',
-  payload: { routeKey: 'desktop-main', providerId: 'rig-builder', authorization: 'user-action' }
-});
-
-const resolved = await window.slopsmith.capabilities.dispatch({
-  capability: 'audio-effects',
-  command: 'resolve-plan',
-  source: 'nam_tone',
-  payload: { routeKey: 'desktop-main', target: { settingsKey: 'settings-v1-...' } }
-});
-```
-
-Providers should store public song/tone routing through the host-owned mapping index and keep their own preset or chain rows private. The mapping's `provider_ref` is opaque to core: NAM Tone can use a preset id, Rig Builder can use a chain/preset id, and each provider resolves that reference in `chain.resolve`.
-
-```js
-await window.slopsmith.audioEffects.upsertMapping({
-  song_key: playbackTarget.settingsKey,
-  filename: playbackTarget.filename, // optional migration/debug context
-  tone_key: 'Dist',
-  provider_id: 'rig-builder',
-  provider_ref: 'chain:99',
-  label: 'Full Rig Builder chain',
-  source: 'manual',
-  active: true
-});
-
-const mappings = await window.slopsmith.audioEffects.listMappings({
-  song_key: playbackTarget.settingsKey,
-  tone_key: 'Dist'
-});
-```
-
-Only one mapping is active for a `song_key + tone_key` at a time, but multiple providers may have rows for the same song/tone. The active row decides which provider core asks first; provider fallback remains explicit through provider priority and `fallbackProviderId` during `loadPlan(...)`.
-
-Browser or native executors should declare both provider scope and plan scope. A NAM-only browser executor should not claim Rig Builder plans just because it can load NAM files:
-
-```js
-window.slopsmith.audioEffects.registerExecutor({
-  executorId: 'nam-tone-browser-wasm',
-  pluginId: 'nam_tone',
-  routeKey: 'desktop-main',
-  providerIds: ['nam-tone'],
-  supportedKinds: ['nam', 'ir'],
-  maxStages: 2,
-  sourceMode: 'browser',
-  loadChainPlan: request => loadNamToneWasmPlan(request)
-});
-```
-
-Trusted Desktop can advertise broader support, while provider-specific browser executors should keep their `providerIds`, `supportedKinds`, and `maxStages` as narrow as the runtime actually supports.
-
-The desktop executor is the trust boundary for physical loading. It should treat `assetRef` and `stateRef` values as opaque provider references, validate them through provider-owned lookup code, enforce local policy, then load or reject processor stages. Browser diagnostics should report route/provider/outcome summaries only.
-
 ## Audio Input And Monitoring Requester

-Plugins that need live instrument input should declare requester/observer intent and let the host expose redaction-safe source identity. Diagnostics must not contain raw device labels, stable hardware ids, or audio buffers.
+Plugins that need live instrument input declare requester/observer intent and let the host expose redaction-safe source identity. Diagnostics must not contain raw device labels, stable hardware ids, or audio buffers.

 ```json
 {
@@ -274,7 +162,7 @@ Plugins that need live instrument input should declare requester/observer intent
      "requests": ["inspect", "list-sources", "select-source", "open-source", "close-source"],
      "observes": ["source-registered", "source-selected", "source-opened", "source-open-degraded", "source-closed", "permission-denied"],
      "mode": "active",
-      "compatibility": "shim-allowed",
+      "compatibility": "none",
      "ownership": "requester-only",
      "safety": "sensitive",
      "version": 1
@@ -284,7 +172,7 @@ Plugins that need live instrument input should declare requester/observer intent
      "requests": ["inspect", "list-providers", "select-provider", "start", "stop", "set-direct-monitor"],
      "observes": ["provider-registered", "provider-selected", "provider-selection-required", "monitoring-started", "monitoring-degraded", "monitoring-unavailable", "monitoring-failed", "monitoring-denied", "monitoring-stopped", "direct-monitor-changed"],
      "mode": "active",
-      "compatibility": "shim-allowed",
+      "compatibility": "none",
      "ownership": "requester-only",
      "safety": "sensitive",
      "version": 1
@@ -400,7 +288,7 @@ The Stems plugin remains the provider/owner of actual stem playback state. `core
      "operations": ["stem.get-state", "stem.apply-automation", "stem.restore-automation"],
      "events": ["owner-available", "automation-applied", "automation-restored", "automation-overridden", "claim-orphaned"],
      "mode": "active",
-      "compatibility": "shim-allowed",
+      "compatibility": "none",
      "ownership": "exclusive-owner",
      "safety": "safe",
      "version": 1
@@ -411,7 +299,7 @@ The Stems plugin remains the provider/owner of actual stem playback state. `core

 ## Playback Requester And Observer

-Plugins that need to inspect or coordinate song transport should declare `playback` requester/observer intent and use the capability dispatch surface instead of wrapping `window.playSong` or scraping the `<audio>` element. Raw media handles stay private to core; diagnostics expose only pseudonymous targets, sanitized timing, route, loop, requester, observer, and recent outcome summaries.
+Plugins that need to inspect or coordinate song transport declare `playback` requester/observer intent and use the capability dispatch surface. Raw media handles stay private to core; diagnostics expose only pseudonymous targets, sanitized timing, route, loop, requester, observer, and recent outcome summaries.

 ```json
 {
@@ -424,7 +312,7 @@ Plugins that need to inspect or coordinate song transport should declare `playba
      "requests": ["inspect", "pause", "resume", "seek", "set-loop", "clear-loop"],
      "observes": ["ready", "started", "paused", "resumed", "seeking", "seeked", "stopped", "loop-set", "loop-cleared"],
      "mode": "active",
-      "compatibility": "shim-allowed",
+      "compatibility": "none",
      "ownership": "requester-only",
      "safety": "safe",
      "version": 1
@@ -455,106 +343,10 @@ if (state.status !== 'idle') {
 }
 ```

-During migration, legacy uses of `window.playSong`, `song:*` events, `window.slopsmith.seek`, and loop helpers remain available and are recorded as playback bridge hits. Treat bridge hits as migration telemetry: native capability requests should eventually cover normal plugin workflows so unexpected legacy hits disappear from diagnostics.
-
-## Progression Requester And Observer
-
-Plugins that report gameplay outcomes or react to player progression (spec 010) should declare `progression` requester/observer intent and use capability dispatch instead of private fetches. Externally postable event types are whitelisted (`minigame_run` in v1); `song_completed` is server-derived inside `/api/stats` and is denied at this surface. Backend plugin code can use the plugin-context hook `record_progression_event` instead (the minigames hub does).
-
-```json
-{
-  "id": "my_minigame",
-  "name": "My Minigame",
-  "standards": ["capability-pipelines.v1"],
-  "capabilities": {
-    "progression": {
-      "roles": ["requester", "observer"],
-      "requests": ["inspect", "record-event"],
-      "observes": ["challenge-completed", "quest-completed", "path-level-up", "rank-changed", "db-changed"],
-      "mode": "active",
-      "compatibility": "none",
-      "ownership": "requester-only",
-      "safety": "safe",
-      "version": 1
-    }
-  }
-}
-```
-
-`buy-item` and `equip-item` require a visible user gesture (`authorization: "user-action"`). Decibels are play-earned only; plugins must not present any purchase path.
-
-```js
-const api = window.slopsmith.capabilities;
-
-const result = await api.dispatch({
-  capability: 'progression',
-  command: 'record-event',
-  source: 'my_minigame',
-  payload: { type: 'minigame_run', payload: { game_id: 'my-minigame', score: 420 } },
-});
-// result.payload lists challenges/quests completed by this event (toast UX).
-
-window.slopsmith.on('progression:quest-completed', (e) => {
-  console.log('quest done:', e.detail.title, '+' + e.detail.reward_db + ' dB');
-});
-```
-
 ## Future Expansion Domains

 Some domain names are reserved for expected future contracts, but they are not registered in the runtime graph yet. For example, `ui.player-panels` is documented as a likely panel-host surface, but Slopsmith does not currently expose a capability command for panel contributions. See [capability-roadmap.md](capability-roadmap.md) for the PR1 domain set and deferred-domain checklist.

-Plugins should not declare future expansion domains until the corresponding host workflow ships. For current integrations, prefer active domains such as `library`, `playback`, `audio-mix`, `audio-input`, `audio-monitoring`, or `stems` intent matching the recipes above.
+Do not declare future expansion domains until the corresponding host workflow ships. For current integrations, use active domains such as `library`, `playback`, `audio-mix`, `audio-input`, `audio-monitoring`, or `stems` intent matching the recipes above.

-Invalid capability metadata is excluded from the capability graph, but legacy manifest fields still load through their existing app paths. The `library` workflow is native in PR1 and does not use compatibility shim metadata. Unsupported `capability-pipelines` versions are reported as incompatible and their runtime handlers must not execute.
-
-## Library Card Action (`ui.library-card-injection`)
-
-Delivered in fee[dB]ack v0.3.0 (frontend host). Plugins add per-song actions to
-the library cards by REGISTERING them instead of DOM-injecting onto
-`.song-card`. The library renders applicable actions in each card's action
-menu, dispatches the handler on click, and emits `action-result` events;
-the owner is visible in the Capability Inspector.
-
-```json
-{
-  "id": "my_card_action",
-  "name": "My Card Action",
-  "standards": ["capability-pipelines.v1"],
-  "capabilities": {
-    "ui.library-card-injection": {
-      "roles": ["provider"],
-      "operations": ["action.run"],
-      "events": ["action-registered", "action-result"],
-      "mode": "active",
-      "compatibility": "none",
-      "safety": "safe",
-      "version": 1
-    }
-  }
-}
-```
-
-Register the action from the plugin's `screen.js`:
-
-```js
-window.slopsmith.libraryCardActions.register({
-  id: 'my_card_action.run',
-  pluginId: 'my_card_action',
-  label: 'Do the thing',
-  placement: 'menu',                 // 'menu' | 'inline' | 'overlay'
-  order: 50,
-  applies: (song) => song.format === 'sloppak',  // shown only when relevant
-  enabled: (song) => true,
-  run: async (song, ctx) => {        // ctx.source identifies the surface
-    await fetch('/api/plugins/my_card_action/run', {
-      method: 'POST', headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ filename: song.filename }),
-    });
-  },
-});
-```
-
-`register(spec)` returns an `unregister()` fn. The host owns rendering,
-applicability, enabled state, and `action-result` events — plugins do not touch
-library DOM. Legacy `.song-card` DOM injection still works in the 0.2.x UI;
-migrate to this for the v0.3.0 native library.
+Invalid capability metadata is excluded from the capability graph. The `library` workflow is native in PR1 and does not use compatibility shim metadata. Unsupported `capability-pipelines` versions are reported as incompatible and their runtime handlers must not execute.
@@ -0,0 +1,45 @@
+# Audio mixer fader registration
+
+Plugins that produce audio outside the song's `<audio>` element (NAM amp output, synth voices, etc.) can register a labeled fader so users can balance them against the song from one mixer popover in the player controls.
+
+This is the slopsmith#87 contract.
+
+## Registration
+
+```js
+function _registerFader() {
+    const api = window.slopsmith && window.slopsmith.audio;
+    if (!api) return;
+    api.registerFader({
+        id: 'my_plugin',           // unique key
+        label: 'My Plugin',        // shown above the fader
+        unit: 'dB',                // optional suffix shown next to the value (e.g. '%', 'dB')
+        min: 0, max: 2, step: 0.05,
+        defaultValue: 1.0,
+        getValue: () => _myCurrentVolume,        // read current value
+        setValue: (v) => _setMyVolume(v),         // write + persist + apply
+    });
+}
+
+if (window.slopsmith && window.slopsmith.audio) {
+    _registerFader();
+} else {
+    window.addEventListener('slopsmith:audio:ready', _registerFader, { once: true });
+}
+```
+
+## Contract
+
+- **Persistence is the plugin's responsibility.** The registry calls `getValue()` when the popover opens and after each `setValue()` during slider drags to re-sync the displayed value.
+- **`getValue()` must be cheap and side-effect-free.**
+- **`setValue()` must update whatever backing state `getValue()` reads synchronously** — pair it with whatever your plugin already does internally (write the GainNode, persist to `localStorage`, update any in-plugin label).
+- **Use `unregisterFader(id)`** when your plugin is teardown-able and you want the strip to disappear; otherwise keep it registered so the user's setting persists across toggle states.
+
+## Lifecycle event
+
+`slopsmith:audio:ready` fires once on `window` when the audio mixer registry is ready. Guard registration against this event for plugins that load before the mixer.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-visualization-contracts.md](plugin-visualization-contracts.md) — visualization counterpart
@@ -0,0 +1,86 @@
+# Plugin diagnostics contribution
+
+Slopsmith ships an **Export Diagnostics** feature (Settings → Export Diagnostics) that bundles a redacted set of host + plugin state into a zip the user can share with maintainers. Plugins have three independent opt-ins for contributing to this bundle.
+
+The bundle layout and per-file schemas are documented in [diagnostics-bundle-spec.md](diagnostics-bundle-spec.md). This doc covers how plugins integrate.
+
+## 1. `manifest.diagnostics.server_files` — opt-in file capture
+
+Declare files under `context["config_dir"]` to copy verbatim into the bundle:
+
+```json
+{
+  "diagnostics": {
+    "server_files": ["my_plugin.diag.json", "my_plugin_models/active.json"]
+  }
+}
+```
+
+Rules (same as `settings.server_files`):
+- Relpaths only. No `..`, no abs paths, no backslashes, no leading dots.
+- Files land at `plugins/<plugin_id>/<relpath>` inside the bundle.
+- Encoded as `{"encoding": "json", "data": <parsed>}` if `.json` parses cleanly, base64 otherwise.
+
+Use this for **snapshot-style state** — small DB excerpts, model lists, last-error files. Don't use it for backups (that's `settings.server_files`).
+
+## 2. `manifest.diagnostics.callable` — opt-in dynamic capture
+
+Declare a Python entry point that produces diagnostics at export time:
+
+```json
+{
+  "diagnostics": {
+    "callable": "diagnostics:collect"
+  }
+}
+```
+
+The form is `"<module>:<function>"`. The module is resolved lazily via `load_sibling` when the user clicks Export, then called as:
+
+```python
+# plugins/my_plugin/diagnostics.py
+def collect(ctx):
+    """ctx is {"plugin_id": str, "config_dir": Path}."""
+    return {
+        "schema": "my_plugin.diag.v1",
+        "active_preset": _read_active_preset(ctx["config_dir"]),
+        "model_count": len(list((ctx["config_dir"] / "models").glob("*.pt"))),
+    }
+```
+
+Return-type handling:
+- `dict` / `list` → written to `plugins/<id>/callable.json`
+- `bytes` → `callable.bin`
+- `str` → `callable.txt`
+
+Exceptions are caught and appended to the bundle's `manifest.notes` — a buggy plugin never crashes the export.
+
+## 3. Frontend contribution (slopsmith#166)
+
+Plugins that hold useful debug state in the browser (active model name, last user input, internal counters) can push it into the bundle from `screen.js`:
+
+```js
+window.slopsmith.diagnostics.contribute('my_plugin', {
+    schema: 'my_plugin.client_diag.v1',
+    active_preset: getActivePreset(),
+    last_error: _lastError,
+});
+```
+
+- **Idempotent.** Repeated calls overwrite the previous value.
+- Whatever was last contributed before the user hits Export Diagnostics is what lands in `plugins/<plugin_id>/client.json`.
+- Available namespace: `window.slopsmith.diagnostics.{contribute, snapshotConsole, snapshotHardware, snapshotUa, snapshotLocalStorage, snapshotContributions}`.
+- Loaded from `static/diagnostics.js` ASAP in `<head>` so the console-wrap is in place before any other script runs.
+
+## Best practices
+
+- **Embed a `schema` field** (e.g. `"my_plugin.diag.v1"`) in JSON returned by `callable` so future tooling can dispatch by version.
+- **Keep payloads small (< 100 KB).** Diagnostics are not a backup channel — that's `settings.server_files`.
+- **Don't include secrets, API keys, or session tokens.** Bundles are shared with maintainers / posted to GitHub issues.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [diagnostics-bundle-spec.md](diagnostics-bundle-spec.md) — full bundle layout + per-file schemas
+- [plugin-manifest.md](plugin-manifest.md) — declaring `diagnostics` fields
+- [plugin-logging.md](plugin-logging.md) — `log.exception()` writes traceback into the diagnostics log capture
@@ -0,0 +1,64 @@
+# Plugin keyboard shortcuts
+
+Plugins can register keyboard shortcuts via the global `window.registerShortcut()` function. Shortcuts appear in the `?` help panel.
+
+## Registration
+
+```js
+window.registerShortcut({
+    key: 'k',                       // key value (e.key) or key code (e.code)
+    description: 'Toggle my view',  // shown in the help panel
+    scope: 'player',                // 'global' | 'player' | 'library' | 'settings' | 'plugin-{id}'
+    condition: () => _isMyViewActive, // optional guard
+    handler: (e) => _myAction()      // called when shortcut triggers
+});
+```
+
+## Scope
+
+Scope controls when the shortcut is active:
+
+- **`global`** — works on any screen
+- **`player`** — only on the player screen
+- **`library`** — only on the home/favorites screens
+- **`settings`** — only on the settings screen
+- **`plugin-{id}`** — only when your plugin's screen is active
+
+## Panel-scoped shortcuts
+
+For plugins that create multiple panels (e.g., splitscreen), shortcuts are automatically scoped to the active panel. Use `const panel = window.createShortcutPanel(id)` to create a panel (keep the returned reference so you can call `panel.clearShortcuts()` during cleanup) and `window.setActiveShortcutPanel(id)` to switch between them. Each panel has its own shortcut registry, so multiple panels can have the same key without collisions.
+
+## Condition
+
+`condition` is an optional guard function. If it returns false, the shortcut is skipped even if in scope.
+
+## Key matching
+
+The handler matches against both `e.key` (character produced) and `e.code` (physical key). Use `e.key` for letters/symbols that depend on keyboard layout, and `e.code` for special keys (e.g. `Space`, `ArrowLeft`).
+
+## Cleanup
+
+Clean up with `window.unregisterShortcut(key, scope)`. **You must pass the same scope you registered with** — the default is `'global'` and won't match `player`/`library`/`settings`/`plugin-*` bindings.
+
+For panel-scoped shortcuts, prefer `panel.clearShortcuts()` over per-key unregister calls.
+
+## Built-in shortcuts
+
+| Key | Description |
+|-----|-------------|
+| `?` | Show keyboard shortcuts panel (global) |
+| `Space` | Play/Pause (player only) |
+| `←` / `→` | Seek ±5 seconds (player only) |
+| `Escape` | Back to library (player only) |
+| `[` / `]` | Audio offset ±10ms (Shift: ±50ms) (player only) |
+
+Don't override these. The `?` panel is the canonical reference for users.
+
+## Debugging
+
+Open the browser console and type `_listShortcuts()` to inspect every registered shortcut, its scope, and its source plugin.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [testing-plugins.md](testing-plugins.md) — Playwright tests for shortcut behaviour
@@ -0,0 +1,67 @@
+# Plugin logging
+
+Use `context["log"]` for all backend plugin output. It is a stdlib `logging.Logger` namespaced to `slopsmith.plugin.<id>`, pre-configured with the app-wide level, format (including JSON mode), and correlation IDs. **Never use `print()`** — it bypasses correlation context and log rotation.
+
+## Backend usage
+
+```python
+def setup(app, context):
+    log = context["log"]
+    log.info("plugin ready")
+    log.warning("optional dependency %r not found, feature disabled", dep)
+    try:
+        risky_init()
+    except Exception:
+        log.exception("unhandled error during setup")  # auto-captures traceback
+```
+
+## CLI entry-point fallback
+
+For helper scripts that also run as `__main__`, add a stdlib fallback so the logger works without the server pipeline:
+
+```python
+if __name__ == "__main__":
+    import logging
+    logging.basicConfig(level=logging.INFO, format="%(levelname)s %(message)s")
+```
+
+## How it's wired
+
+The plugin loader assigns each plugin a logger before calling `setup()`:
+
+```python
+context["log"] = logging.getLogger(f"slopsmith.plugin.{plugin_id}")
+```
+
+That logger inherits from the root `slopsmith` logger, which is configured by `logging_setup.configure_logging()` (called from `main.py` before uvicorn boots). It respects:
+
+- **`LOG_LEVEL`** — `DEBUG | INFO | WARNING | ERROR` (default `INFO`)
+- **`LOG_FORMAT`** — `json | text` (default `text` — coloured console)
+- **`LOG_FILE`** — optional path for a persistent log file (e.g. `/config/slopsmith.log`)
+- **Correlation IDs** — each HTTP request carries `X-Request-ID`; structlog injects it into every log line during that request's lifetime. WebSocket sessions get their own `ws_conn_id` contextvar bound at accept time.
+
+## Verifying
+
+Look for your plugin's logger name in the console output:
+
+```text
+INFO     slopsmith.plugin.my_plugin: plugin ready
+```
+
+Switch `LOG_FORMAT=json` to see structured output:
+
+```json
+{"timestamp": "...", "level": "info", "logger": "slopsmith.plugin.my_plugin", "event": "plugin ready", "request_id": "..."}
+```
+
+## Common mistakes
+
+- **Using `print()` inside `setup()` or request handlers.** `print()` goes to stdout, bypasses level filtering, log rotation, JSON formatting, and correlation IDs. Audit your plugin with `grep -nR 'print(' plugins/<id>/`.
+- **Creating a new logger with `logging.getLogger("my_plugin")`.** This creates an unparented logger that doesn't inherit slopsmith's configuration. Always use the one passed via `context["log"]`.
+- **Logging at `INFO` in hot paths.** Default `LOG_LEVEL` is `INFO`, so `log.info(...)` inside a per-frame or per-message loop floods output. Use `log.debug(...)` for hot-path tracing.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-manifest.md](plugin-manifest.md) — the `routes.py` / `setup(app, context)` contract
+- [plugin-diagnostics.md](plugin-diagnostics.md) — capturing logs into the diagnostics bundle
@@ -0,0 +1,234 @@
+# `plugin.json` manifest reference
+
+Every plugin lives in `plugins/<name>/` and must declare a `plugin.json` manifest. JSON Schema for this format ships at [`schema/plugin.schema.json`](../schema/plugin.schema.json) and is enforced in CI for in-tree plugins.
+
+## Full example
+
+```json
+{
+  "id": "my_plugin",
+  "name": "My Plugin",
+  "version": "1.0.0",
+  "private": false,
+  "standards": ["capability-pipelines.v1", "plugin-runtime-idempotent.v1"],
+  "screen": "screen.html",
+  "script": "screen.js",
+  "styles": "assets/plugin.css",
+  "routes": "routes.py",
+  "settings": {
+    "html": "settings.html",
+    "server_files": ["my_plugin.db", "my_plugin_models/"]
+  },
+  "diagnostics": {
+    "server_files": ["my_plugin.diag.json"],
+    "callable": "diagnostics:collect"
+  },
+  "settings_schema": {
+    "schema_version": "1",
+    "packable_keys": ["enabled"]
+  },
+  "ui": {
+    "settings": [{ "id": "my-plugin-settings", "region": "plugin-settings", "label": "My Plugin" }],
+    "ui.plugin-screens": [{ "id": "my-plugin-screen", "region": "plugin.main", "label": "My Plugin" }]
+  },
+  "capabilities": {
+    "library": {
+      "roles": ["provider"],
+      "operations": ["query-page", "query-artists", "query-stats"],
+      "mode": "active",
+      "compatibility": "none",
+      "ownership": "multi-provider",
+      "safety": "safe",
+      "version": 1
+    }
+  }
+}
+```
+
+All fields except `id` and `name` are optional. Runtime files such as `screen`, `script`, `routes`, and `settings.html` should correspond to declared `capabilities`, `ui`, diagnostics, or settings metadata.
+
+## Fields
+
+### `id` (required, string)
+
+Snake-case identifier. Used to namespace `localStorage` keys, build the plugin's screen id (`plugin-<id>`), namespace the backend logger (`slopsmith.plugin.<id>`), and as the directory name in diagnostics bundles. Cannot contain slashes, dots are encoded by the sibling-import loader (see [plugin-sibling-imports.md](plugin-sibling-imports.md)).
+
+### `name` (required, string)
+
+Human-readable name shown in UI surfaces.
+
+### `version` (string, optional)
+
+Plain semver string. Advisory only — the plugin loader does not consume this. Plugins commonly include it for publishing/tooling purposes.
+
+### `private` (boolean, optional)
+
+Advisory metadata for plugin authors. Not consumed by the loader.
+
+### `standards` (string[], expected)
+
+Versioned contracts the plugin participates in. Plugin manifests are expected to declare `"capability-pipelines.v1"` for Slopsmith-facing behavior and metadata. Omit it only for metadata-only or transitional manifests with no capability participation yet.
+
+Declare `"plugin-runtime-idempotent.v1"` only when repeated script hydration cannot duplicate wrappers, listeners, timers, DOM roots, diagnostics contributors, jobs, media nodes, or capability participants.
+
+### `capability_api` (object, optional)
+
+Explicit capability API marker. Most plugins can use the compact `standards` form instead:
+
+```json
+{ "capability_api": { "standard": "capability-pipelines.v1", "version": 1 } }
+```
+
+### `screen` (string, optional)
+
+Path to HTML file (relative to plugin dir). Mounted at `#plugin-<id>` in the SPA.
+
+### `script` (string, optional)
+
+Path to JS file (relative to plugin dir). Loaded via `<script>` tag in global scope. Wrap in an IIFE.
+
+### `styles` (string, optional)
+
+Path to a plugin-owned compiled stylesheet under `assets/`, for example `"assets/plugin.css"`. Use this when a plugin ships Tailwind utilities that core's prebuilt stylesheet cannot know about, especially arbitrary-value classes in runtime-installed plugins. The stylesheet must be built ahead of time with Tailwind `preflight: false`; Slopsmith injects one versioned `<link>` for the plugin. See [plugin-styles.md](plugin-styles.md).
+
+### `routes` (string, optional)
+
+Path to Python file exporting `setup(app, context)`. See "Backend routes" below.
+
+### `settings` (object, optional)
+
+`{ "html": string, "server_files": string[] }`
+
+- **`settings.html`** — settings-panel HTML.
+- **`settings.server_files`** — **opt-in** for the unified Settings export/import flow (slopsmith#113). List of relpaths under `context["config_dir"]` that the plugin wants included in user-triggered backups. A trailing `/` denotes a directory (recurse).
+
+  Rules:
+  - Relpaths only. Absolute paths, drive letters, `..` segments, and backslashes are rejected at load time with a `[Plugin]` warning.
+  - The same allowlist is consulted at both export and import: a bundle that references a file the *importing host*'s manifest no longer declares is skipped with a warning (handles plugin updates between export and import). A bundle that references a file your host's manifest never declared is also skipped — no surprise writes.
+  - Files are encoded as `{"encoding": "json", "data": <parsed>}` for `.json` files that parse cleanly (diff-friendly), `{"encoding": "base64", "data": "..."}` otherwise (sqlite, model blobs, IRs).
+  - Plugins own their internal data migration. Importing a bundle whose data schema predates your current code restores bytes verbatim — your plugin must cope at next load.
+  - Symlinks are skipped on export and never followed on import.
+
+  Plugins that omit this field have no server-side files exported; their state lives entirely in browser `localStorage`, which is bundled wholesale on every export.
+
+### `diagnostics` (object, optional)
+
+`{ "server_files": string[], "callable": string }`
+
+**Opt-in** for the troubleshooting bundle (slopsmith#166 — Settings → Export Diagnostics). Two independent fields:
+
+- **`diagnostics.server_files`** — same allowlist semantics as `settings.server_files`: relpaths under `context["config_dir"]`, no `..`, no abs paths, no backslashes, no leading dots. Files listed here are copied verbatim into `plugins/<plugin_id>/<relpath>` inside the bundle. Use this for snapshot-style state (small DB excerpts, model lists, last-error files).
+- **`diagnostics.callable`** — `"<module>:<function>"` (e.g. `"diagnostics:collect"`). Resolved lazily via `load_sibling` when the user clicks Export, then called as `func({"plugin_id": "...", "config_dir": Path(...)})`. Return `dict`/`list` → written to `plugins/<id>/callable.json`; `bytes` → `callable.bin`; `str` → `callable.txt`. Exceptions are caught and appended to the bundle's `manifest.notes` — a buggy plugin never crashes the export.
+
+See [plugin-diagnostics.md](plugin-diagnostics.md) for full diagnostics integration patterns.
+
+### `settings_schema` (object, optional)
+
+Redaction-safe settings metadata for support tooling and capability diagnostics. Use this to describe schema/version and packable key names; do not store user settings values, paths, tokens, or plugin-private payloads here.
+
+### `ui` / `ui_contributions` (object, optional)
+
+Native UI contribution declarations keyed by UI domain or surface. Use these whenever a plugin contributes settings panels, plugin screens, player controls, overlays, tours, or other host-visible UI so Slopsmith can attribute UI to stable contribution records.
+
+Example:
+
+```json
+{
+  "ui": {
+    "settings": [{ "id": "my-plugin-settings", "region": "plugin-settings", "label": "My Plugin" }],
+    "ui.player-overlays": [{ "id": "my-plugin-overlay", "region": "player.overlays.highway", "label": "My Overlay" }]
+  }
+}
+```
+
+Contribution ids must be stable and unique per plugin. Keep metadata redaction-safe: no settings values, DOM handles, local paths, callbacks, or private payloads.
+
+### `capabilities` (object, expected for app-facing behavior)
+
+Native `capability-pipelines.v1` declarations keyed by capability domain. They describe what the plugin owns, provides, requests, observes, or emits before the runtime script hydrates, and are the default way plugin behavior is made visible to Slopsmith.
+
+```json
+{
+  "standards": ["capability-pipelines.v1"],
+  "capabilities": {
+    "library": {
+      "roles": ["provider"],
+      "operations": ["query-page", "query-artists", "query-stats", "tuning-names", "get-art", "sync-song"],
+      "description": "Adds a browsable library source.",
+      "mode": "active",
+      "compatibility": "none",
+      "ownership": "multi-provider",
+      "safety": "safe",
+      "version": 1
+    },
+    "playback": {
+      "roles": ["observer"],
+      "observes": ["loading", "ready", "stopped", "ended"],
+      "description": "Observes playback lifecycle through playback capability events.",
+      "mode": "active",
+      "compatibility": "none",
+      "ownership": "observer-only",
+      "safety": "safe",
+      "version": 1
+    }
+  }
+}
+```
+
+Supported declaration fields include:
+
+- `roles`: `owner`, `coordinator`, `provider`, `observer`, `requester`, `transformer`, `handler`, `validator`, `short-circuiter`, `contributor`
+- `commands`, `operations`, `requests`, `observes`, `emits`, `events`: string arrays naming public commands, provider operations, or events
+- `kind`: `command`, `provider-coordinator`, `event`, `diagnostic`, `privileged`
+- `mode`: `active`, `optional`, `legacy-shim`, `disabled`
+- `compatibility`: prefer `none` for new declarations
+- `ownership`: `exclusive-owner`, `multi-provider`, `observer-only`, `requester-only`, `privileged`, `diagnostic-only`
+- `safety`: `safe`, `privileged`, `sensitive`, `diagnostic-only`
+- `description` / `summary`: short redaction-safe text for local tooling
+- `version`: `1`
+
+Invalid capability metadata is rejected by schema validation and ignored by runtime capability tooling. Fix invalid metadata rather than relying on undocumented runtime behavior.
+
+### `license` (string, optional but recommended)
+
+SPDX identifier. Contributions must use `AGPL-3.0-only`. See [CONTRIBUTING.md](../CONTRIBUTING.md).
+
+## Backend routes — `setup(app, context)`
+
+`routes.py` must export `setup(app, context)`. The `context` dict provides:
+
+- `config_dir` — persistent config path (`Path`)
+- `get_dlc_dir()` — returns the DLC folder `Path`
+- `extract_meta()` — metadata extraction callable
+- `meta_db` — shared `MetadataDB` instance
+- `get_sloppak_cache_dir()` — sloppak cache `Path`
+- `load_sibling(name)` — loads a sibling module from this plugin's directory under a unique, namespaced module name. See [plugin-sibling-imports.md](plugin-sibling-imports.md).
+- `log` — stdlib `logging.Logger` namespaced to `slopsmith.plugin.<id>`. Pre-configured with the app-wide level, format (including JSON mode), and correlation IDs. Use this for all backend plugin output instead of `print()`. See [plugin-logging.md](plugin-logging.md).
+
+Prefer native capability declarations and provider registration for Slopsmith-facing behavior. Backend plugins should not open ad hoc SQLite connections to core databases or treat database tables as a public integration surface. If a legacy or core-provided route path already needs metadata access through `context["meta_db"]`, use the shared `MetadataDB` instance and its synchronized methods only; do not bypass its `threading.Lock` protection with direct SQLite access.
+
+Example:
+
+```python
+def setup(app, context):
+    log = context["log"]
+    extractor = context["load_sibling"]("extractor")
+
+    @app.get("/api/my_plugin/status")
+    def status():
+        return {"ready": True}
+
+    log.info("my_plugin ready")
+```
+
+## Validation
+
+Run the local validator skill `/plugin-validate` (Claude Code) or the CI workflow `.github/workflows/validate-plugins.yml`. Both consume [`schema/plugin.schema.json`](../schema/plugin.schema.json), including capability-pipelines metadata.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-logging.md](plugin-logging.md) — `context["log"]` pattern
+- [plugin-sibling-imports.md](plugin-sibling-imports.md) — `load_sibling`
+- [plugin-diagnostics.md](plugin-diagnostics.md) — diagnostics opt-in details
+- [diagnostics-bundle-spec.md](diagnostics-bundle-spec.md) — full diagnostics bundle layout
@@ -3,62 +3,396 @@
  "$id": "https://slopsmith.local/contracts/plugin-manifest-capabilities.schema.json",
  "title": "Slopsmith Plugin Manifest Capability Contract",
  "type": "object",
-  "required": ["id", "name"],
+  "required": [
+    "id",
+    "name"
+  ],
  "properties": {
-    "id": { "type": "string", "minLength": 1, "pattern": "^[A-Za-z0-9_.-]+$" },
-    "name": { "type": "string", "minLength": 1 },
-    "version": { "type": ["string", "null"] },
-    "private": { "type": "boolean" },
-    "standards": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+    "id": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^[A-Za-z0-9_.-]+$"
+    },
+    "name": {
+      "type": "string",
+      "minLength": 1
+    },
+    "version": {
+      "type": [
+        "string",
+        "null"
+      ]
+    },
+    "private": {
+      "type": "boolean"
+    },
+    "standards": {
+      "type": "array",
+      "items": {
+        "type": "string",
+        "minLength": 1
+      },
+      "uniqueItems": true
+    },
    "capability_api": {
      "type": "object",
-      "properties": { "standard": { "const": "capability-pipelines.v1" }, "version": { "const": 1 } },
+      "properties": {
+        "standard": {
+          "const": "capability-pipelines.v1"
+        },
+        "version": {
+          "const": 1
+        }
+      },
      "additionalProperties": false
    },
    "capabilities": {
      "type": "object",
-      "propertyNames": { "$ref": "#/$defs/domainName" },
-      "additionalProperties": { "$ref": "#/$defs/capabilityDeclaration" }
+      "propertyNames": {
+        "$ref": "#/$defs/domainName"
+      },
+      "additionalProperties": {
+        "$ref": "#/$defs/capabilityDeclaration"
+      }
    },
-    "ui_contributions": { "type": "object", "propertyNames": { "$ref": "#/$defs/domainName" }, "additionalProperties": { "$ref": "#/$defs/contributionList" } },
-    "ui": { "type": "object", "propertyNames": { "$ref": "#/$defs/domainName" }, "additionalProperties": { "$ref": "#/$defs/contributionList" } },
-    "runtime_domains": { "type": "object", "propertyNames": { "$ref": "#/$defs/domainName" }, "additionalProperties": { "$ref": "#/$defs/domainDeclaration" } },
-    "domains": { "type": "object", "propertyNames": { "$ref": "#/$defs/domainName" }, "additionalProperties": { "$ref": "#/$defs/domainDeclaration" } },
-    "settings_schema": { "type": "object" },
-    "nav": {}, "screen": {}, "script": {}, "routes": {}, "settings": {}, "diagnostics": {}, "type": { "type": "string" }, "tour": {},
-    "description": { "type": "string", "description": "Short one-sentence summary of the plugin, surfaced on the v3 Pedalboard Plugins page (clamped to ~2 lines). Optional and additive." },
-    "category": { "type": "string", "description": "Which pedalboard the plugin sits on in the v3 Plugins page. Suggested values: 'audio', 'creation', 'practice', 'game', 'tools'. Free-form; unknown/absent values fall back to a curated default then 'other'. Optional and additive." },
-    "icon": { "type": "string", "minLength": 1, "pattern": "^assets/(?!.*\\.\\.)[^\\\\?#]+$", "description": "Plugin-root-relative path under assets/ (e.g. 'assets/thumb.png') to a thumbnail (~square, ~256x256 PNG/SVG) shown as the pedal graphic on the v3 Plugins page. Same containment rule as `styles`. If omitted, the loader auto-detects assets/thumb.png; failing that the UI shows a default pedal graphic. Optional and additive." },
-    "styles": { "type": "string", "minLength": 1, "pattern": "^assets/(?!.*\\.\\.)[^\\\\?#]+$", "description": "Plugin-root-relative path under assets/ (e.g. 'assets/plugin.css') to a compiled, preflight-off Tailwind stylesheet the frontend injects as a <link>. Must stay under assets/ with no '..', backslash, or query/fragment. See docs/plugin-styles.md." }
+    "ui_contributions": {
+      "type": "object",
+      "propertyNames": {
+        "$ref": "#/$defs/domainName"
+      },
+      "additionalProperties": {
+        "$ref": "#/$defs/contributionList"
+      }
+    },
+    "ui": {
+      "type": "object",
+      "propertyNames": {
+        "$ref": "#/$defs/domainName"
+      },
+      "additionalProperties": {
+        "$ref": "#/$defs/contributionList"
+      }
+    },
+    "runtime_domains": {
+      "type": "object",
+      "propertyNames": {
+        "$ref": "#/$defs/domainName"
+      },
+      "additionalProperties": {
+        "$ref": "#/$defs/domainDeclaration"
+      }
+    },
+    "domains": {
+      "type": "object",
+      "propertyNames": {
+        "$ref": "#/$defs/domainName"
+      },
+      "additionalProperties": {
+        "$ref": "#/$defs/domainDeclaration"
+      }
+    },
+    "settings_schema": {
+      "type": "object"
+    },
+    "nav": {},
+    "screen": {
+      "$ref": "#/$defs/pluginRelpath"
+    },
+    "script": {
+      "$ref": "#/$defs/pluginRelpath"
+    },
+    "routes": {
+      "$ref": "#/$defs/pluginRelpath"
+    },
+    "settings": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "html": {
+          "$ref": "#/$defs/pluginRelpath"
+        },
+        "server_files": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "not": {
+              "pattern": "^/|^[a-zA-Z]:|\\\\|(^|/)\\.\\.(/|$)|//|(^|/)\\.(/|$)|^\\."
+            }
+          },
+          "uniqueItems": true
+        }
+      }
+    },
+    "diagnostics": {},
+    "type": {
+      "type": "string"
+    },
+    "tour": {
+      "$ref": "#/$defs/pluginRelpath"
+    },
+    "description": {
+      "type": "string",
+      "description": "Short one-sentence summary of the plugin, surfaced on the v3 Pedalboard Plugins page (clamped to ~2 lines). Optional and additive."
+    },
+    "category": {
+      "type": "string",
+      "description": "Which pedalboard the plugin sits on in the v3 Plugins page. Suggested values: 'audio', 'creation', 'practice', 'game', 'tools'. Free-form; unknown/absent values fall back to a curated default then 'other'. Optional and additive."
+    },
+    "icon": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^assets/(?!.*\\.\\.)[^\\\\?#]+$",
+      "description": "Plugin-root-relative path under assets/ (e.g. 'assets/thumb.png') to a thumbnail (~square, ~256x256 PNG/SVG) shown as the pedal graphic on the v3 Plugins page. Same containment rule as `styles`. If omitted, the loader auto-detects assets/thumb.png; failing that the UI shows a default pedal graphic. Optional and additive."
+    },
+    "styles": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^assets/(?!.*\\.\\.)[^\\\\?#]+$",
+      "description": "Plugin-root-relative path under assets/ (e.g. 'assets/plugin.css') to a compiled, preflight-off Tailwind stylesheet the frontend injects as a <link>. Must stay under assets/ with no '..', backslash, query, or fragment. See docs/plugin-styles.md."
+    }
  },
  "additionalProperties": true,
  "$defs": {
-    "domainName": { "type": "string", "minLength": 1, "pattern": "^[A-Za-z0-9_.:-]+$" },
+    "pluginRelpath": {
+      "type": "string",
+      "minLength": 1,
+      "not": {
+        "pattern": "^/|^[a-zA-Z]:|\\\\|(^|/)\\.\\.(/|$)|//|(^|/)\\.(/|$)|^\\.|[?#]"
+      }
+    },
+    "domainName": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^[A-Za-z0-9_.:-]+$"
+    },
    "capabilityDeclaration": {
      "type": "object",
      "properties": {
-        "roles": { "type": "array", "items": { "enum": ["owner", "provider", "observer", "requester", "transformer", "handler", "validator", "short-circuiter", "contributor"] }, "uniqueItems": true },
-        "commands": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
-        "operations": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
-        "requests": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
-        "observes": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
-        "emits": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
-        "events": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
-        "kind": { "enum": ["command", "provider-coordinator", "event", "diagnostic", "privileged"] },
-        "mode": { "enum": ["active", "optional", "legacy-shim", "disabled"] },
-        "compatibility": { "enum": ["none", "shim-allowed", "degrade-noop", "required", "legacy-window-shim"] },
-        "ownership": { "enum": ["exclusive-owner", "multi-provider", "observer-only", "requester-only", "privileged", "diagnostic-only"] },
-        "safety": { "enum": ["safe", "privileged", "sensitive", "diagnostic-only"] },
-        "order": { "type": "object", "properties": { "fixed": { "type": "boolean" }, "before": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true }, "after": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true } }, "additionalProperties": false },
-        "provider_policy": { "type": "object" },
-        "settings": { "type": "array", "description": "Declarative per-instance control descriptors (toggle / range / select) a participant exposes for a consuming host to render generically. Domain-agnostic in shape; how a host applies a chosen value is defined by each capability domain's contract (the visualization domain requires an applySetting(key, value) method on the renderer instance).", "items": { "type": "object", "required": ["key", "type"], "properties": { "key": { "type": "string", "minLength": 1 }, "label": { "type": "string" }, "type": { "enum": ["toggle", "range", "select"] }, "default": {}, "min": { "type": "number" }, "max": { "type": "number" }, "step": { "type": "number" }, "options": { "type": "array", "items": { "type": "object", "required": ["id"], "properties": { "id": { "type": "string", "minLength": 1 }, "label": { "type": "string" } }, "additionalProperties": false } } }, "additionalProperties": false } },
-        "description": { "type": "string" },
-        "summary": { "type": "string" },
-        "version": { "const": 1 }
+        "roles": {
+          "type": "array",
+          "items": {
+            "enum": [
+              "owner",
+              "coordinator",
+              "provider",
+              "observer",
+              "requester",
+              "transformer",
+              "handler",
+              "validator",
+              "short-circuiter",
+              "contributor"
+            ]
+          },
+          "uniqueItems": true
+        },
+        "commands": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "minLength": 1
+          },
+          "uniqueItems": true
+        },
+        "operations": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "minLength": 1
+          },
+          "uniqueItems": true
+        },
+        "requests": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "minLength": 1
+          },
+          "uniqueItems": true
+        },
+        "observes": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "minLength": 1
+          },
+          "uniqueItems": true
+        },
+        "emits": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "minLength": 1
+          },
+          "uniqueItems": true
+        },
+        "events": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "minLength": 1
+          },
+          "uniqueItems": true
+        },
+        "kind": {
+          "enum": [
+            "command",
+            "provider-coordinator",
+            "event",
+            "diagnostic",
+            "privileged"
+          ]
+        },
+        "mode": {
+          "enum": [
+            "active",
+            "optional",
+            "legacy-shim",
+            "disabled"
+          ]
+        },
+        "compatibility": {
+          "enum": [
+            "none",
+            "shim-allowed",
+            "degrade-noop",
+            "required",
+            "legacy-window-shim"
+          ]
+        },
+        "ownership": {
+          "enum": [
+            "exclusive-owner",
+            "multi-provider",
+            "observer-only",
+            "requester-only",
+            "privileged",
+            "diagnostic-only"
+          ]
+        },
+        "safety": {
+          "enum": [
+            "safe",
+            "privileged",
+            "sensitive",
+            "diagnostic-only"
+          ]
+        },
+        "order": {
+          "type": "object",
+          "properties": {
+            "fixed": {
+              "type": "boolean"
+            },
+            "before": {
+              "type": "array",
+              "items": {
+                "type": "string",
+                "minLength": 1
+              },
+              "uniqueItems": true
+            },
+            "after": {
+              "type": "array",
+              "items": {
+                "type": "string",
+                "minLength": 1
+              },
+              "uniqueItems": true
+            }
+          },
+          "additionalProperties": false
+        },
+        "provider_policy": {
+          "type": "object"
+        },
+        "description": {
+          "type": "string"
+        },
+        "summary": {
+          "type": "string"
+        },
+        "version": {
+          "const": 1
+        }
      },
      "additionalProperties": false
    },
-    "domainDeclaration": { "oneOf": [{ "type": "object", "properties": { "role": { "type": "string", "minLength": 1 }, "roles": { "type": "array", "items": { "type": "string", "minLength": 1 } }, "ownership": { "enum": ["exclusive-owner", "multi-provider", "observer-only", "requester-only", "privileged", "diagnostic-only"] }, "safety": { "enum": ["safe", "privileged", "sensitive", "diagnostic-only"] }, "legacy_source": { "type": "string", "minLength": 1 } }, "additionalProperties": true }, { "type": "array" }] },
-    "contributionList": { "type": "array", "items": { "type": "object", "required": ["id"], "properties": { "id": { "type": "string", "minLength": 1 }, "region": { "type": "string", "minLength": 1 }, "label": { "type": "string" }, "order": { "type": ["number", "integer", "string"] } }, "additionalProperties": true } }
+    "domainDeclaration": {
+      "oneOf": [
+        {
+          "type": "object",
+          "properties": {
+            "role": {
+              "type": "string",
+              "minLength": 1
+            },
+            "roles": {
+              "type": "array",
+              "items": {
+                "type": "string",
+                "minLength": 1
+              }
+            },
+            "ownership": {
+              "enum": [
+                "exclusive-owner",
+                "multi-provider",
+                "observer-only",
+                "requester-only",
+                "privileged",
+                "diagnostic-only"
+              ]
+            },
+            "safety": {
+              "enum": [
+                "safe",
+                "privileged",
+                "sensitive",
+                "diagnostic-only"
+              ]
+            },
+            "legacy_source": {
+              "type": "string",
+              "minLength": 1
+            }
+          },
+          "additionalProperties": true
+        },
+        {
+          "type": "array"
+        }
+      ]
+    },
+    "contributionList": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": [
+          "id"
+        ],
+        "properties": {
+          "id": {
+            "type": "string",
+            "minLength": 1
+          },
+          "region": {
+            "type": "string",
+            "minLength": 1
+          },
+          "label": {
+            "type": "string"
+          },
+          "order": {
+            "type": [
+              "number",
+              "integer",
+              "string"
+            ]
+          }
+        },
+        "additionalProperties": true
+      }
+    }
  }
 }
@@ -0,0 +1,48 @@
+# Plugin sibling imports — `load_sibling`
+
+When a backend plugin spans multiple Python files, **use `context["load_sibling"]`** rather than bare `import` statements. This is the slopsmith#33 contract.
+
+## The problem
+
+The plugin loader inserts each plugin's directory onto `sys.path` so `from extractor import X` works. But Python caches imports by **module name** in `sys.modules`. Two plugins that each ship a top-level `extractor.py` (or any other generic name — `util.py`, `client.py`, `parser.py`, `config.py`, …) collide: whichever loads first wins, and the other plugin's `from extractor import X` either gets the wrong module or fails with `cannot import name 'X' from 'extractor'`.
+
+## The fix
+
+`context["load_sibling"](name)` loads the sibling under a namespaced module name `plugin_<id>.<name>`, so each plugin gets its own copy. The `<id>` portion is bijectively encoded so reverse-DNS-style ids like `com.example.foo` work without colliding: `_` → `_5f_`, `.` → `_2e_`.
+
+```python
+def setup(app, context):
+    extractor = context["load_sibling"]("extractor")
+    ArchiveReader = extractor.ArchiveReader
+    # …
+```
+
+## Notes
+
+- **`name` is a bare module name** — no `.py` suffix, no slashes, no `.`. The helper raises `ValueError` for path traversal / format issues and `ImportError` for missing files.
+- **Both single-file siblings (`extractor.py`) and package-form siblings (`extractor/__init__.py`) work.** Package form wins when both exist (matches CPython's import-resolution precedence).
+- **Relative imports between siblings work** — `from .shared import X` in a top-level helper, `from ..shared import X` from inside a sibling package. The synthetic parent package `plugin_<id>` carries the plugin directory in its `__path__`.
+- **`from . import sibling` (attribute-style) also resolves**: loaded children are exposed as attributes on the parent package.
+- **Repeat calls return the cached module.** Concurrent first-time calls are serialized via per-module locks so no caller observes a half-initialized module.
+- **Don't mix `load_sibling` and bare `import` for the same module** — they'd execute the file twice and split module-level state.
+
+## Migration
+
+Bare `import sibling` from `routes.py` still works during the transition period, but the loader prints a startup warning when it detects two plugins shipping a same-named top-level module — covering both `.py` files and package directories. Migrate to `load_sibling` to silence the warning and immunize your plugin from future ecosystem collisions.
+
+## Verification
+
+The collision-detection logic is encoded in `tests/test_plugins.py`. Run:
+
+```bash
+pytest tests/test_plugins.py -v
+```
+
+If you're authoring a plugin with a top-level helper, add a test that imports your plugin under a `reset_plugin_state` fixture to confirm clean import behaviour. See [testing-plugins.md](testing-plugins.md).
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-manifest.md](plugin-manifest.md) — declaring `routes.py`
+- [plugin-logging.md](plugin-logging.md) — `context["log"]` (also exposed via `context`)
+- [testing-plugins.md](testing-plugins.md) — `reset_plugin_state` fixture
@@ -0,0 +1,198 @@
+# Plugin visualization contracts
+
+Slopsmith supports two ways for a plugin to participate in the main player's visuals. They coexist; the **setRenderer** contract is the default for any viz that draws a highway-shaped surface, and **overlays** handle layered decorations on top. A third orthogonal contract — **note-state provider** — lets scorers feed per-note judgments back into whichever renderer is active.
+
+**Pick the right shape:**
+- Replacing the whole highway drawing on the existing highway canvas (your renderer owns its rendering context / resources; `createHighway()` still owns the canvas element and the rAF loop)? → **setRenderer** (section 1). Enters the viz picker. Works in both the main player and per-panel under splitscreen.
+- Adding a layer on top of whichever viz is active? → **Overlay** (section 2). Navbar toggle, not in the picker.
+- Scoring plugin that wants renderers to "light up" notes on correct hits? → **Note-state provider** (section 3). Orthogonal — can coexist with overlay HUDs.
+
+## 1. setRenderer contract (slopsmith#36) — preferred
+
+Plugins that want to replace the main highway's draw function (per panel, per session) export a renderer factory on `window.slopsmithViz_<id>` where `<id>` matches the `id` in `plugin.json` (`type: "visualization"` required). The factory returns an object matching this shape:
+
+```js
+window.slopsmithViz_my_viz = function () {
+    return {
+        // Required canvas context type. Default '2d' if omitted.
+        // highway.js reads this BEFORE calling init() so it can
+        // replace the underlying <canvas> element if the current
+        // one is locked to a different context type (see "Canvas
+        // context-type swapping" below).
+        contextType: '2d', // or 'webgl2'
+        init(canvas, bundle) {
+            // One-time setup. Own your getContext() call here —
+            // acquire '2d' or 'webgl2' depending on the renderer.
+            // The canvas you receive is guaranteed to either be
+            // unbound or already bound to your declared contextType.
+            this.ctx = canvas.getContext('2d');
+        },
+        draw(bundle) {
+            // Called each requestAnimationFrame tick by the factory.
+            // `bundle` is a snapshot with: currentTime, songInfo, isReady,
+            // notes, chords, anchors (all difficulty-filter-aware),
+            // beats, sections, chordTemplates, stringCount, lyrics,
+            // toneChanges, toneBase, mastery, hasPhraseData, inverted,
+            // lefty, renderScale, lyricsVisible, the 2D coordinate
+            // helpers project and fretX, and getNoteState (see below).
+            // `stringCount` is the active arrangement's string count (4
+            // for bass, 6 for guitar, 7+ for extended-range GP imports —
+            // size string-indexed geometry against this, not a hardcoded
+            // 6). If your renderer needs lefty-aware text rendering, check
+            // bundle.lefty and apply the mirror transform yourself —
+            // a bundle-level helper isn't provided because it would
+            // need your renderer's own context, not the factory's.
+            //
+            // bundle.getNoteState(note, chartTime) (slopsmith#254) — call
+            // this per visible chart note / chord-note to find out whether
+            // a scorer (note_detect) has flagged it 'hit' / 'active' (a
+            // sustain currently being held correctly) / 'miss', so the gem
+            // itself can light up / a held sustain can glow instead of
+            // relying on an overlay ring. Returns null when no provider is
+            // registered or it reports nothing for this note; otherwise
+            // { state: 'hit'|'active'|'miss', alpha: 0..1, color: string|null }.
+            // For chord notes pass the chord's time (note_detect keys its
+            // judgments by `${time}_${string}_${fret}`). 'hit' and 'active'
+            // are both "lit" — a renderer may treat them identically; the
+            // provider owns all fade timing via `alpha` and by simply
+            // ceasing to return state when the effect should end.
+        },
+        resize(w, h) {
+            // Optional. Canvas dims already updated; re-create WebGL
+            // framebuffers / reset 2D transforms here.
+        },
+        destroy() {
+            // Optional. Release resources, remove DOM nodes, null refs.
+            // Called before setRenderer() swaps to another renderer
+            // and on highway.stop().
+        },
+    };
+};
+```
+
+Selecting this plugin in the main-player viz picker — or in splitscreen's per-panel picker — calls `highway.setRenderer(factory())` on the existing highway instance. The built-in 2D highway is the default renderer and is restored by passing nullish — `setRenderer(null)` and `setRenderer(undefined)` both work (the implementation gates on `r == null`). Splitscreen panels create one `createHighway()` per panel and each independently consults the picker, so N panels can run different renderers (or N copies of the same renderer with different arrangements) without coordination.
+
+### Lifecycle contract
+
+The factory returns a single renderer instance that may go through multiple `init() → ... → destroy()` cycles as the user navigates between songs or screens. Specifically:
+
+- `init(canvas, bundle)` runs when the highway has a canvas and the renderer takes over drawing. This is when to acquire `getContext()`, build shaders / meshes / DOM nodes, and register listeners.
+- `draw(bundle)` runs on every rAF frame once the WebSocket `ready` message has fired and until the renderer is replaced or the highway stops. It is **not** called during the loading / reconnect window (between `api.init()` + `stop()` and the next `ready`) — that would hand the renderer half-populated chart arrays. Renderers that want to show a "loading" state can read `bundle.isReady` inside a future-widened contract, but today the factory gates `draw` behind the ready flag and `isReady` is only informational once it does fire.
+- `destroy()` runs when the renderer is replaced via another `setRenderer(...)` call, OR when `highway.stop()` is called (e.g. the user navigates away from the player). It releases everything `init()` acquired.
+- **After `destroy()`, the same instance may receive another `init()` call** — this happens on `playSong()` which does `stop()` → `init()` to reuse the same canvas element for the next song. Renderers must tolerate `init()` being called again on an instance that was previously destroyed. Practically: null your refs in destroy, re-acquire them in init.
+- `destroy()` is skipped when it would run on an un-init'd renderer — if a caller does `setRenderer(x)` before the highway ever init'd (possible when restoring a saved picker selection at page load), `x.destroy()` is not called until `x.init()` has run at least once.
+- `resize(w, h)` is optional; runs after init and whenever the canvas dimensions change.
+
+### Key rules
+
+- The factory **returns a fresh object on each call** — important for splitscreen, where multiple panels will each get an independent instance.
+- The renderer **owns its own rendering context** (2D or WebGL). Factory will not call getContext for you.
+- **Canvas context-type swapping.** Browsers lock a `<canvas>` to the first context type successfully acquired for its lifetime: once `getContext('2d')` succeeds, `getContext('webgl2')` on that same canvas returns `null`, and vice versa. To let arbitrary 2D ⇄ WebGL renderer swaps work mid-session, `highway.setRenderer()` reads the next renderer's `contextType` before calling its `init()` and, if it differs from the type currently bound, replaces the underlying `<canvas>` element with a fresh one via `oldCanvas.cloneNode(false)` followed by `oldCanvas.replaceWith(newCanvas)`. The factory then calls the renderer's `init(newCanvas, bundle)` with the fresh element so its `getContext()` succeeds. Practical implications:
+  - **What survives the swap.** `cloneNode(false)` preserves *every HTML attribute* on the element — `id`, `class`, inline `style`, all `data-*` and `aria-*` attributes, `role`, `tabindex`, the attribute form of `width`/`height`, and anything else a plugin attached. DOM position is preserved by `replaceWith()`, so siblings, parents, and surrounding layout are unaffected.
+  - **What does NOT survive.** Event listeners attached via `addEventListener` are NOT cloned, and expando properties set imperatively on the JavaScript object (such as the bound rendering context, or any `canvas._myPlugin = …`-style data a plugin attached) are not carried over either. The bound rendering context being left behind on the detached element is exactly what allows the new canvas to start fresh and accept a different `getContext()` call. Note: `canvas.width`/`canvas.height` *are* reflected HTML attributes, so those values do survive the clone; `api.resize()` re-applies the backing-store dimensions on the new element after the swap regardless.
+  - Renderers must **declare `contextType`** on the returned instance (`'2d'` or `'webgl2'`; absent → `'2d'`). Factories may also expose it as a static (`window.slopsmithViz_<id>.contextType = 'webgl2'`) so core can read it before constructing the renderer — used today by Auto-mode evaluation.
+  - Plugins that hold a stale reference to the highway canvas across renderer swaps — including any code that registered listeners directly on the canvas element rather than on `window`/`document` — should listen for the `highway:canvas-replaced` event on `window.slopsmith` and re-acquire / re-register. `window.slopsmith.emit` dispatches a `CustomEvent`, so the payload `{ oldCanvas, newCanvas, contextType }` lives on `event.detail`, not on the event object itself:
+    ```js
+    window.slopsmith.on('highway:canvas-replaced', (event) => {
+        const { oldCanvas, newCanvas, contextType } = event.detail;
+        // re-acquire / re-register against newCanvas
+    });
+    ```
+    Plugins that re-query `document.getElementById('highway')` lazily inside their own event handlers don't need this listener — they pick up the new element automatically (it keeps `id="highway"`).
+  - **`highway:visibility`** — fired on `window.slopsmith` whenever the highway canvas transitions between displayed and hidden. Detection is DOM-based via `canvas.offsetParent === null` (catches `display:none` on the canvas or any ancestor — e.g. splitscreen's `#highway` hide) or whatever a host explicitly sets via `highway.setVisible(bool)`. While `visible === false`, core skips the rAF `renderer.draw(bundle)` call AND the default 2D draw, so renderers don't have to no-op themselves. The event is emitted only on transitions (including the first one after `init()`), not every frame. Payload `{ visible, canvas }` lives on `event.detail`:
+    ```js
+    window.slopsmith.on('highway:visibility', (event) => {
+        const { visible, canvas } = event.detail;
+        // Toggle any sibling DOM your renderer mounts. The 3D Highway
+        // renderer hides its `.h3d-wrap` overlay here so `display:none`
+        // on `#highway` actually hides the visible output.
+    });
+    ```
+    Renderers that only paint to the slopsmith canvas don't need this listener — the rAF skip is enough. Renderers that mount sibling DOM (separate WebGL contexts, overlays, etc.) do.
+  - **`highway.setVisible(bool | null)`** — forces the visibility state regardless of `offsetParent`. Pass `null` to clear the override and resume DOM-based detection. Useful when the host hides the highway via `visibility:hidden`, `opacity:0`, transforms, or clipping rather than `display:none`. The override re-emits any resulting transition immediately rather than waiting for the next rAF tick.
+  - Default-renderer ctx is closure-cached. The replace path nulls the closure ctx so stale draw paths short-circuit; the next default-renderer `init()` re-acquires the 2D context from the new canvas cleanly.
+- `draw(bundle)` receives difficulty-filtered arrays — never read from `_filteredNotes` or other internals.
+- `_drawHooks` fire for the default 2D renderer (the factory calls them at the end of each frame). Custom WebGL renderers that maintain a 2D overlay canvas (like the bundled 3D highway) also call `window.highway.fireDrawHooks(ctx, W, H)` on that overlay so overlay plugins continue to work regardless of which renderer is active. Custom renderers without a 2D overlay context should not attempt to fire hooks.
+
+### Auto mode — `matchesArrangement(songInfo)` (optional)
+
+The viz picker prepends an "Auto (match arrangement)" entry that is the default selection on fresh installs. When Auto is active, core evaluates registered viz factories on every `song:ready` and swaps the renderer to the first factory whose `matchesArrangement(songInfo)` predicate returns truthy. No match → the built-in 2D highway.
+
+Declare the predicate as a static on the factory (not the instance) so core can evaluate it without constructing a throwaway renderer:
+
+```js
+window.slopsmithViz_piano = function () { /* ... */ };
+window.slopsmithViz_piano.matchesArrangement = function (songInfo) {
+    return /keys|piano|synth/i.test((songInfo && songInfo.arrangement) || '');
+};
+```
+
+- `songInfo` is the highway's live song_info snapshot — `arrangement`, `tuning`, `capo`, `arrangement_index`, `filename`, `artist`, `title`, etc. May be `{}` before the first song loads.
+- Factories without `matchesArrangement` are skipped during auto-selection — the correct default for arrangement-agnostic viz (tabview, jumpingtab) that only make sense as manual picks.
+- Explicit picker selections override Auto and are persisted to `localStorage.vizSelection`, so the pinned choice survives page reloads until the user switches back to "Auto" (which also persists). Picking "Auto" re-evaluates against the current song immediately. In contexts where `localStorage` is unavailable (private mode, sandboxed iframes, some test runners) persistence falls back to the current picker `<option>` value, which still overrides Auto for as long as the page stays loaded.
+- When an Auto-selected renderer fails and core emits `viz:reverted`, the picker falls back to the built-in default and disables auto-switching until the user re-selects Auto.
+- First match wins (picker order), so the registration order of plugins is the tiebreaker. Keep predicates narrow to avoid stealing songs from more specialized viz.
+
+**WebGL viz in Auto mode.** Auto evaluation runs on every `song:ready` regardless of which renderer is active. Auto-installing a WebGL renderer when the canvas is currently 2D — or reverting from a WebGL Auto pick to the default 2D — works without a reload because `setRenderer` swaps the canvas element when `contextType` differs (see "Canvas context-type swapping" above). WebGL viz can therefore safely declare `matchesArrangement` and rely on Auto. For 3D Highway specifically, `_canRun3D()` in app.js still gates Auto from picking it on machines without WebGL2 — that fallback is independent of canvas swapping.
+
+## 2. Overlay contract — for add-on layers
+
+Plugins that add a layer on top of whichever visualization is active — HUDs, fretboard diagrams, chord labels, practice feedback — don't replace the renderer. They manage their own canvas, their own rAF loop, and a toggle button somewhere visible (typically a navbar pill), reading public highway state via the getters:
+
+- `highway.getTime()` / `highway.getBeats()` — current playback position
+- `highway.getNotes()` / `highway.getChords()` — difficulty-filter-aware arrays
+- `highway.getChordTemplates()` — chord shape lookup table; index by `chord.id` from `getChords()` to get `{ name, fingers, frets }`. `fingers` and `frets` are per-string arrays (length matches the tuning's string count); within `fingers`, `-1` = unused, `0` = open string, `n > 0` = finger number. RS XML sources populate real fingerings; GP imports currently emit all `-1` since pre-import sources don't carry finger data. Not filter-aware: templates are static metadata, every `chord_id` referenced by `getChords()` is guaranteed valid.
+- `highway.getSongInfo()` — tuning, arrangement, capo
+- `highway.getStringCount()` — number of strings on the active arrangement (4 for bass, 6 for guitar, 7+ for extended-range GP imports). Derived server-side as `max(notes-max-string + 1, name-based fallback, len(tuning))` where the tuning length only contributes when it isn't the RS-XML padded 6-string form (sloppak / GP-imported sources carry trimmed tuning lengths). The name-based fallback is 4 for arrangements containing "bass" (case-insensitive) and 6 otherwise. This combination handles partial-string-usage charts (a 6-string lead that never plays string 5), extended-range GP imports (5-string bass, 7-string guitar), and sloppaks that explicitly encode the instrument range — without requiring plugins to do their own arrangement-name matching.
+- `highway.getLefty()` / `highway.getInverted()` — mirror + invert state
+
+Overlays do NOT appear in the viz picker and do NOT declare `"type": "visualization"` in `plugin.json`. They coexist with whichever renderer (default 2D, 3D highway, piano, ...) the user has picked.
+
+### Key rules
+
+- **Own your rAF + canvas** — don't piggyback on `_drawHooks` or on `createHighway`'s rendering context. Draw hooks fire for the default 2D renderer and for custom renderers that explicitly call `window.highway.fireDrawHooks(ctx, W, H)` (e.g. the bundled 3D highway fires them on its 2D overlay canvas), but not for every custom renderer.
+- **Re-read state every frame** — overlay output must track whatever the current renderer is drawing. Don't cache note positions across frames.
+- **Respect lefty + invert toggles** — if the overlay depicts strings or frets, mirror using the same transforms the active renderer would.
+- **If you position with `highway.project` / `highway.fretX` (the 2D-highway geometry), gate on `highway.isDefaultRenderer()`** — those helpers describe the *built-in 2D* highway's depth curve and fret zoom. When a custom renderer (3D highway, piano, …) is active your draw hook still fires (on that renderer's 2D overlay layer), but those coordinates won't match its scene — markers land in arbitrary places. Skip rendering when `isDefaultRenderer()` is false; the custom renderer owns that feedback. Renderer-agnostic overlays (fretboard diagram, chord-label HUD — they use `getNotes()`/`getChordTemplates()` + their own layout) don't need this guard.
+- **Clean up on toggle-off** — cancel rAF and remove/hide the overlay canvas so inactive overlays aren't wasting frames.
+
+Reference: [fretboard plugin](https://github.com/byrongamatos/slopsmith-plugin-fretboard) — canonical overlay implementation (navbar toggle, own canvas, 80ms active-note window).
+
+### Why two contracts?
+
+setRenderer plugs into an existing highway — main-player or splitscreen-panel — reusing its WebSocket and data parsing, so the common "I want a different look for the same data" case is zero boilerplate AND multi-instance for free. Overlays compose with whatever renderer is active — they decorate rather than replace, so multiple can stack (fretboard + chord labels + practice feedback) without fighting over the canvas.
+
+A previous standalone-pane contract (`window.createMyVisualization({ container })` with its own WebSocket per pane) was used by splitscreen pre-Wave-C. It's been retired now that splitscreen calls `setRenderer` on per-panel `createHighway()` instances; if you find references in older plugin docs or external integration guides, those describe the legacy path.
+
+## 3. Note-state provider — for scorers that want renderers to "light up" notes (slopsmith#254)
+
+A scoring plugin (note_detect) can publish a per-note judgment so whichever renderer is active draws the **gem itself** lit on a correct hit, and keeps a sustain trail glowing while it's still being played correctly — instead of a separate overlay ring floating near the note.
+
+```js
+// In the plugin (after resolving the highway instance):
+highway.setNoteStateProvider((note, chartTime) => {
+    // `note` is the chart note object ({ t, s, f, sus, ... }); for chord
+    // notes `chartTime` is the chord's time. Return one of:
+    //   - falsy  → no special state (render normally)
+    //   - 'hit'    — struck correctly; renderer lights the gem
+    //   - 'active' — a sustained note is right now being held correctly
+    //   - 'miss'   — missed; renderer may red-wash the gem
+    //   - { state: <one of the above>, alpha?: 0..1, color?: '#rrggbb' }
+    // You own all fade timing: return a decaying `alpha` for a struck-note
+    // glow, `alpha: 1` (or a bare string) for a held sustain, and stop
+    // returning state when the effect should end. Keep it cheap — it's
+    // called per visible note per renderer per frame.
+});
+// On teardown:  highway.setNoteStateProvider(null);
+```
+
+- Only one provider is active at a time (last `setNoteStateProvider` wins). `highway.getNoteStateProvider()` returns the current one (or null).
+- The built-in 2D highway consults it in `drawNote` / `drawSustains` / the chord-frame path: 'hit'/'active' → bright string colour + additive halo + a contained "sizzle" (crackling sparks, throbbing core, a shockwave ring on a fresh strike) on the gem and a bright (vs dim) sustain trail; 'miss' → faint red wash. The bundled **3D highway** reads the same data via `bundle.getNoteState` (bright string-tinted outline + bright body + glowing sustain + a contained sparkle hugging the note rect on hit/active; red outline + suppressed body on miss). Custom renderers that want it call `bundle.getNoteState(note, chartTime)` — it null-guards and returns the normalized `{ state, alpha, color }` (or null).
+- This is orthogonal to the overlay contract: note_detect remains an overlay (HUD, diagnostic miss markers, the "currently detected" indicator) *and* a scorer that feeds this provider. A renderer that ignores `getNoteState` simply doesn't light gems — nothing breaks.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-manifest.md](plugin-manifest.md) — declaring `"type": "visualization"`
+- [websocket-protocol.md](websocket-protocol.md) — the WebSocket stream that drives `bundle`
+- [plugin-audio-mixer.md](plugin-audio-mixer.md) — companion contract for audio-producing plugins
@@ -435,7 +435,7 @@ Always use `yaml.safe_dump` (not `yaml.dump`) and pass `sort_keys=False` so the

 ### 4.3. Reading (JavaScript, plugin-side)

-Plugins typically don't read the sloppak file directly — they consume the `/ws/highway/{filename}` WebSocket stream (see `CLAUDE.md` for the message protocol), which produces the same shapes. If you specifically need raw manifest access from the browser, expose it through a custom backend route in your plugin's `routes.py` and fetch it.
+Plugins typically don't read the sloppak file directly — they consume the `/ws/highway/{filename}` WebSocket stream (see [`websocket-protocol.md`](websocket-protocol.md) for the message protocol), which produces the same shapes. If you specifically need raw manifest access from the browser, expose it through a custom backend route in your plugin's `routes.py` and fetch it.

 ---

@@ -935,5 +935,5 @@ The full pytest suite (`pytest`) must stay green before any PR.
 | Drum tab vocabulary and wire helpers | [lib/drums.py](../lib/drums.py) |
 | Notation vocabulary and wire helpers | [lib/notation.py](../lib/notation.py) |
 | Live streaming over WebSocket (consumes the same shapes) | `server.py` (`/ws/highway/{filename}`) |
-| The plugin system (where new viz consumers go) | [CLAUDE.md](../CLAUDE.md) — Plugin System section |
+| The plugin system (where new viz consumers go) | [docs/PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) + [docs/plugin-visualization-contracts.md](plugin-visualization-contracts.md) |
 | Tests | [tests/test_sloppak.py](../tests/test_sloppak.py), [tests/test_sloppak_convert.py](../tests/test_sloppak_convert.py) |
@@ -0,0 +1,104 @@
+# Testing plugins
+
+Slopsmith has three test surfaces — Python unit/integration tests (pytest), JS plugin-API contract tests (Node), and end-to-end browser tests (Playwright). This doc covers what to use when.
+
+## Test layout
+
+```text
+tests/
+├── conftest.py          Shared pytest fixtures (isolate_logging)
+├── test_plugins.py      Plugin loader + load_sibling + collision tests (includes reset_plugin_state)
+├── test_song.py         Wire-format serialization round-trips
+├── test_*.py            Per-feature backend tests
+├── js/                  Node --test JS plugin-API contract tests
+└── browser/             Playwright end-to-end tests
+```
+
+## Running tests
+
+```bash
+pytest                              # All Python tests
+pytest tests/test_plugins.py -v     # Specific file
+pytest -k "load_sibling" -v         # Pattern match
+
+npm run test:js                     # Node-native JS contract tests
+npm run install:playwright          # One-time: install Chromium
+npm test                            # Playwright browser tests
+npm run test:headed                 # Playwright with visible browser
+npm run test:debug                  # Playwright inspector
+```
+
+CI runs `pytest` on every push/PR to `main` (Python 3.12).
+
+## Shared fixtures
+
+### `isolate_logging` (in `conftest.py`)
+
+Saves and restores handlers, level, and `propagate` flag on the `slopsmith`, `uvicorn`, `uvicorn.error`, and `uvicorn.access` loggers, plus calls `structlog.reset_defaults()`. **Import into any test module that calls `configure_logging()`** so mutations don't bleed across tests.
+
+```python
+def test_my_log_thing(isolate_logging):
+    configure_logging()
+    # ... assertions
+```
+
+### `reset_plugin_state` (in `test_plugins.py`)
+
+Local fixture used by plugin-loader tests. Saves and restores:
+- `plugins.LOADED_PLUGINS`
+- any `plugin_*` keys in `sys.modules`
+- the bare names the tests simulate (`util`, `extractor`) in `sys.modules`
+- `sys.path` (the loader mutates it)
+
+Also unsets `SLOPSMITH_PLUGINS_DIR` for the test's duration via `monkeypatch` so a CI env that pre-sets it can't leak real user plugins into a tmp-path-driven test.
+
+If you're authoring a plugin that ships top-level helper modules, model new tests on the patterns in `test_plugins.py` — use `reset_plugin_state` to guarantee a clean import slate.
+
+## Backend test patterns
+
+- **Wire-format round-trips.** `test_song.py` is the model: pure serialization tests, no fixtures, narrative docstring. Pattern: build a `Song`/`Arrangement`/`Note`, serialize, deserialize, assert equal.
+- **Loader behaviour.** `test_plugins.py` uses tmp-path-driven plugin roots + `reset_plugin_state` + `_make_plugin` / `_run_load_plugins` helpers. Adopt these helpers for any new loader-touching tests.
+- **Async / WebSocket.** Tests for FastAPI WebSocket endpoints use `httpx.AsyncClient` and `app.websocket_connect()`. See `test_audio.py` and `test_highway_3d_routes.py` for examples.
+
+## JS contract tests (`tests/js/`)
+
+Plain `node --test` files. No browser, no server. Cover the plugin-API surface as exposed on `window.slopsmith` and related globals. Run with `npm run test:js`.
+
+Use these when a plugin needs to assert against the API contract without spinning up a real browser. They run in seconds; CI can grow these without slowing.
+
+## Browser tests (`tests/browser/`)
+
+Playwright + Chromium. `playwright.config.ts` runs serially (`workers: 1`) and boots a real Slopsmith instance via Docker Compose. Traces / video on failure.
+
+What's currently covered: page load and keyboard shortcuts. **No plugin E2E patterns yet** — if you're adding the first one for your plugin, set the precedent. Suggested structure:
+
+```ts
+import { test, expect } from '@playwright/test';
+
+test('my plugin loads its navbar entry', async ({ page }) => {
+    await page.goto('/');
+    await expect(page.getByRole('link', { name: 'My Plugin' })).toBeVisible();
+});
+
+test('my plugin shortcut fires', async ({ page }) => {
+    await page.goto('/#plugin-my_plugin');
+    await page.keyboard.press('k');
+    await expect(page.getByTestId('my-plugin-toggle')).toHaveAttribute('aria-pressed', 'true');
+});
+```
+
+Prefer `data-testid` over text-based selectors so refactors don't break tests.
+
+## Debugging
+
+- **Browser console shortcut inventory.** `_listShortcuts()` prints every registered shortcut, its scope, and source.
+- **`LOG_FORMAT=json pytest`** — get machine-readable test logs.
+- **`pytest -s`** — disable output capture (handy for `print()`-style debug, though prefer `log.debug()` in production code).
+- **Playwright trace viewer** — `npx playwright show-trace test-results/.../trace.zip` after a failure.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-logging.md](plugin-logging.md) — `context["log"]` and why `print()` breaks the logging pipeline
+- [plugin-sibling-imports.md](plugin-sibling-imports.md) — `load_sibling` and the collision tests
+- [plugin-keyboard-shortcuts.md](plugin-keyboard-shortcuts.md) — `window.registerShortcut` and `_listShortcuts()`
@@ -0,0 +1,44 @@
+# Highway WebSocket protocol reference
+
+The highway WebSocket at `/ws/highway/{filename}?arrangement={index}` streams a song's chart data to the player. Plugins that drive their own highway, replace the renderer (see [plugin-visualization-contracts.md](plugin-visualization-contracts.md)), or consume the stream directly all read these frames.
+
+## Message order
+
+Each connection receives the following JSON frames, roughly in this order:
+
+| Message | Shape | Description |
+|---------|-------|-------------|
+| `loading` | `{ type: 'loading', stage }` | Status/progress message during extraction or conversion. |
+| `song_info` | `{ type, title, artist, arrangement, arrangement_index, arrangements, duration, tuning, capo, format, audio_url, audio_error, stems }` | Song metadata. `arrangements` is the full list for the switcher. `audio_url` is `null` when audio is unavailable, in which case `audio_error` is non-null; otherwise `audio_error` is `null`. `stems` is always present — an empty array for non-sloppak songs or sloppak songs with no split stems. `tuning` is an array whose length depends on the source arrangement (typically 6 for guitar, 4 for bass, but extended-range GP imports can be 7/8 for guitar or 5/6 for bass — use `highway.getStringCount()` for the authoritative count). |
+| `beats` | `{ type, data: [{ time, measure }] }` | Beat timestamps with measure numbers. |
+| `sections` | `{ type, data: [{ time, name }] }` | Named sections (Intro, Verse, Chorus, etc.). |
+| `anchors` | `{ type, data: [{ time, fret, width }] }` | Fret zoom anchors. |
+| `chord_templates` | `{ type, data: [{ name, frets: [6] }] }` | Named chord shapes. |
+| `lyrics` | `{ type, data: [{ w, t, d }] }` | Syllables: `w`=word, `t`=time, `d`=duration. `-` joins to previous, `+` = line break. |
+| `tone_changes` | `{ type: 'tone_changes', base, data: [{ time, name }] }` | Optional — tone change events relative to the arrangement base tone; only sent if tones were found. |
+| `notes` | `{ type, data: [{ t, s, f, sus, ho, po, sl, bn, ... }] }` | Single notes. |
+| `chords` | `{ type, data: [{ t, notes: [{ s, f, sus, ... }] }] }` | Chord events. |
+| `phrases` | `{ type, data: [{ start_time, end_time, max_difficulty, levels: [...] }], total }` | Optional — per-phrase difficulty ladder for master-difficulty slider (slopsmith#48). Only sent when the source chart carries multi-level phrase data (legacy archive / phrase-aware sloppak). Sent in chunks (`data` is a batch, `total` is the full count across messages) to avoid multi-MB single frames. Absent for GP imports and legacy sloppak; consumers must treat missing message as "single fixed difficulty — slider disabled". |
+| `ready` | `{ type: 'ready' }` | All data sent — safe to finalize and start rendering. |
+
+## Delivery guarantees
+
+Message delivery is **incremental**. You may receive `loading` updates and `lyrics` before note/chord payloads. `tone_changes` comes after `lyrics` when present and may be omitted entirely. **Do not finalize rendering until you receive `ready`.**
+
+## Consumer notes
+
+- **Tuning array length follows arrangement.** 6 strings for guitar, 4 for bass, more for extended-range GP imports. Use `highway.getStringCount()` for the authoritative count rather than `tuning.length` (which can be the RS-XML padded 6-string form).
+- **Chord templates are static.** Every `chord_id` referenced by `chords` is guaranteed to be present in `chord_templates`.
+- **Notes carry technique fields.** `ho` = hammer-on, `po` = pull-off, `sl` = slide target, `bn` = bend amount. The full set is defined in `lib/song.py`.
+- **Multiple connections are supported.** Split-screen panels, lyrics panes, and jumping-tab panes each open their own WebSocket. By design — don't try to multiplex.
+
+## Phrase payload (slopsmith#48)
+
+`phrases.data` is an array of phrase objects. Each phrase has `start_time`, `end_time`, `max_difficulty`, and `levels`. Each `level` has `difficulty`, `notes`, `chords`, `anchors`, `handshapes` — fully scoped to that phrase. The master-difficulty slider applies a single difficulty across all phrases by selecting the matching level.
+
+## Related
+
+- [PLUGIN_AUTHORING.md](PLUGIN_AUTHORING.md) — guide index
+- [plugin-visualization-contracts.md](plugin-visualization-contracts.md) — bundle shape passed to `draw()`
+- [sloppak-spec.md](sloppak-spec.md) — sloppak format these messages are derived from
+- `lib/song.py` — server-side `Note`, `Chord`, `Arrangement`, `Song` data models
@@ -238,7 +238,7 @@ def _normalize_manifest_sequence(value) -> list:

 _CAPABILITY_STANDARD = "capability-pipelines.v1"
 _VALID_CAPABILITY_ROLES = {
-    "owner", "provider", "observer", "requester", "transformer", "handler",
+    "owner", "coordinator", "provider", "observer", "requester", "transformer", "handler",
    "validator", "short-circuiter", "contributor",
 }
 _VALID_CAPABILITY_MODES = {"active", "optional", "legacy-shim", "disabled"}
@@ -1,5 +1,6 @@
 pytest>=8.0
 httpx>=0.27.0
+jsonschema>=4.0
 # Required by tests/test_lyrics_transcribe.py for the vocals_has_signal
 # RMS-gate tests (silent vs loud WAV generation). Without these the
 # soundfile-backed tests are silently skipped via pytest.importorskip
@@ -0,0 +1,261 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://github.com/slopsmith/slopsmith/blob/main/schema/plugin.schema.json",
+  "title": "Slopsmith plugin manifest",
+  "description": "Schema for plugins/<id>/plugin.json. See docs/plugin-manifest.md for prose. Contributions must use AGPL-3.0-only. Capability metadata follows capability-pipelines.v1 and is intentionally additive.",
+  "type": "object",
+  "additionalProperties": true,
+  "required": ["id", "name"],
+  "properties": {
+    "id": {
+      "type": "string",
+      "pattern": "^[A-Za-z0-9_.-]+$",
+      "description": "Plugin identifier. Snake_case is preferred for bundled plugins. Used to namespace localStorage, the plugin screen id (plugin-<id>), the backend logger (slopsmith.plugin.<id>), and the diagnostics bundle directory. Reverse-DNS form (com.example.foo) is supported via the load_sibling encoding."
+    },
+    "name": {
+      "type": "string",
+      "minLength": 1,
+      "description": "Human-readable name shown in UI surfaces."
+    },
+    "version": {
+      "type": ["string", "null"],
+      "description": "Plain semver string. Advisory only; the plugin loader does not consume this."
+    },
+    "private": {
+      "type": "boolean",
+      "description": "Advisory metadata for plugin authors. Not consumed by the loader."
+    },
+    "standards": {
+      "type": "array",
+      "items": { "type": "string", "minLength": 1 },
+      "uniqueItems": true,
+      "description": "Versioned standards the plugin participates in. Use capability-pipelines.v1 for native capability metadata and plugin-runtime-idempotent.v1 only when repeated hydration cannot duplicate runtime work."
+    },
+    "capability_api": {
+      "type": "object",
+      "properties": {
+        "standard": { "const": "capability-pipelines.v1" },
+        "version": { "const": 1 }
+      },
+      "additionalProperties": false,
+      "description": "Optional explicit capability API version marker. The standards array is the preferred compact form."
+    },
+    "bundled": {
+      "type": "boolean",
+      "description": "True for plugins shipped in-tree with Slopsmith. Used by tooling that distinguishes built-in plugins from user-installed ones."
+    },
+    "type": {
+      "type": "string",
+      "enum": ["visualization"],
+      "description": "Role hint (slopsmith#36). 'visualization' makes the plugin eligible for the viz picker; must pair with a window.slopsmithViz_<id> factory."
+    },
+    "license": {
+      "type": "string",
+      "description": "SPDX identifier. Contributions must use AGPL-3.0-only.",
+      "enum": ["AGPL-3.0-only"]
+    },
+    "nav": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["label", "screen"],
+      "properties": {
+        "label": { "type": "string", "minLength": 1 },
+        "screen": { "type": "string", "pattern": "^[a-z][a-z0-9_-]*$" }
+      },
+      "description": "Optional navigation metadata. Plugin UI declares stable ui contributions for attribution."
+    },
+    "screen": {
+      "$ref": "#/$defs/pluginRelpath",
+      "description": "Relative path to HTML mounted at #plugin-<id>."
+    },
+    "script": {
+      "$ref": "#/$defs/pluginRelpath",
+      "description": "Relative path to JS loaded in global scope on page load. Wrap your code in an IIFE."
+    },
+    "styles": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^assets/(?!.*\\.\\.)[^\\\\?#]+$",
+      "description": "Plugin-root-relative path under assets/ (e.g. 'assets/plugin.css') to a compiled, preflight-off Tailwind stylesheet the frontend injects as a <link>. Must stay under assets/ with no '..', backslash, query, or fragment. See docs/plugin-styles.md."
+    },
+    "routes": {
+      "$ref": "#/$defs/pluginRelpath",
+      "description": "Relative path to Python module exporting setup(app, context). See docs/plugin-manifest.md."
+    },
+    "tour": {
+      "$ref": "#/$defs/pluginRelpath",
+      "description": "Relative path to tour JSON for the in-app onboarding tour."
+    },
+    "settings": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "html": {
+          "$ref": "#/$defs/pluginRelpath",
+          "description": "Relative path to settings-panel HTML."
+        },
+        "server_files": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "not": { "pattern": "^/|^[a-zA-Z]:|\\\\|(^|/)\\.\\.(/|$)|//|(^|/)\\.(/|$)|^\\." },
+            "description": "Relpath under context['config_dir']. No abs paths, no '..', no '//', no './', no leading dotfiles, no backslashes. Mirrors the runtime _validate_relpath rules in plugins/__init__.py so a schema-valid manifest is also load-time-valid. Trailing '/' denotes a directory (recurse)."
+          },
+          "uniqueItems": true,
+          "description": "Opt-in for Settings export/import (slopsmith#113). Files included in user-triggered backups. See docs/plugin-manifest.md."
+        }
+      }
+    },
+    "diagnostics": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "server_files": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "not": { "pattern": "^/|^[a-zA-Z]:|\\\\|(^|/)\\.\\.(/|$)|//|(^|/)\\.(/|$)|^\\." }
+          },
+          "uniqueItems": true,
+          "description": "Files copied verbatim into plugins/<id>/<relpath> inside the diagnostics bundle. Path rules match the settings.server_files pattern (no abs paths, no '..', no '//', no './', no leading dotfiles, no backslashes)."
+        },
+        "callable": {
+          "type": "string",
+          "pattern": "^[a-z][a-z0-9_]*:[A-Za-z_][A-Za-z0-9_]*$",
+          "description": "<module>:<function> resolved via load_sibling at export time. Called with {'plugin_id', 'config_dir'} dict; return dict/list/bytes/str."
+        }
+      },
+      "description": "Opt-in for the Export Diagnostics bundle (slopsmith#166). See docs/plugin-diagnostics.md."
+    },
+    "settings_schema": {
+      "type": "object",
+      "description": "Redaction-safe settings metadata used by capability diagnostics and backup/import tooling. Do not store actual settings values here."
+    },
+    "capabilities": {
+      "type": "object",
+      "propertyNames": { "$ref": "#/$defs/domainName" },
+      "additionalProperties": { "$ref": "#/$defs/capabilityDeclaration" },
+      "description": "Native capability-pipelines.v1 declarations keyed by capability domain."
+    },
+    "ui_contributions": {
+      "type": "object",
+      "propertyNames": { "$ref": "#/$defs/domainName" },
+      "additionalProperties": { "$ref": "#/$defs/contributionList" },
+      "description": "Native UI contribution declarations keyed by UI domain."
+    },
+    "ui": {
+      "type": "object",
+      "propertyNames": { "$ref": "#/$defs/domainName" },
+      "additionalProperties": { "$ref": "#/$defs/contributionList" },
+      "description": "Alias for UI contribution declarations used by current first-party plugin manifests."
+    },
+    "runtime_domains": {
+      "type": "object",
+      "propertyNames": { "$ref": "#/$defs/domainName" },
+      "additionalProperties": { "$ref": "#/$defs/domainDeclaration" },
+      "description": "Reserved runtime-domain metadata. New native declarations use capabilities."
+    },
+    "domains": {
+      "type": "object",
+      "propertyNames": { "$ref": "#/$defs/domainName" },
+      "additionalProperties": { "$ref": "#/$defs/domainDeclaration" },
+      "description": "Runtime-domain declaration alias. New native declarations use capabilities."
+    },
+    "privileged_capabilities": {
+      "type": "array",
+      "items": { "type": "object" },
+      "description": "Manifest-derived privileged workflow summaries. The privileged-capabilities host validates detailed semantics at runtime."
+    },
+    "privileged_compatibility_bridges": {
+      "type": "array",
+      "items": { "type": "object" },
+      "description": "Diagnostics-only bridge declarations for privileged compatibility surfaces."
+    }
+  },
+  "allOf": [
+    {
+      "$comment": "type=visualization requires a script (the window.slopsmithViz_<id> factory)",
+      "if": { "properties": { "type": { "const": "visualization" } }, "required": ["type"] },
+      "then": { "required": ["script"] }
+    }
+  ],
+  "$defs": {
+    "pluginRelpath": {
+      "type": "string",
+      "minLength": 1,
+      "not": { "pattern": "^/|^[a-zA-Z]:|\\\\|(^|/)\\.\\.(/|$)|//|(^|/)\\.(/|$)|^\\.|[?#]" }
+    },
+    "domainName": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^[A-Za-z0-9_.:-]+$"
+    },
+    "capabilityDeclaration": {
+      "type": "object",
+      "properties": {
+        "roles": {
+          "type": "array",
+          "items": {
+            "enum": ["owner", "coordinator", "provider", "observer", "requester", "transformer", "handler", "validator", "short-circuiter", "contributor"]
+          },
+          "uniqueItems": true
+        },
+        "commands": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+        "operations": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+        "requests": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+        "observes": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+        "emits": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+        "events": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+        "kind": { "enum": ["command", "provider-coordinator", "event", "diagnostic", "privileged"] },
+        "mode": { "enum": ["active", "optional", "legacy-shim", "disabled"] },
+        "compatibility": { "enum": ["none", "shim-allowed", "degrade-noop", "required", "legacy-window-shim"] },
+        "ownership": { "enum": ["exclusive-owner", "multi-provider", "observer-only", "requester-only", "privileged", "diagnostic-only"] },
+        "safety": { "enum": ["safe", "privileged", "sensitive", "diagnostic-only"] },
+        "order": {
+          "type": "object",
+          "properties": {
+            "fixed": { "type": "boolean" },
+            "before": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
+            "after": { "type": "array", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true }
+          },
+          "additionalProperties": false
+        },
+        "provider_policy": { "type": "object" },
+        "description": { "type": "string" },
+        "summary": { "type": "string" },
+        "version": { "const": 1 }
+      },
+      "additionalProperties": false
+    },
+    "domainDeclaration": {
+      "oneOf": [
+        {
+          "type": "object",
+          "properties": {
+            "role": { "type": "string", "minLength": 1 },
+            "roles": { "type": "array", "items": { "type": "string", "minLength": 1 } },
+            "ownership": { "enum": ["exclusive-owner", "multi-provider", "observer-only", "requester-only", "privileged", "diagnostic-only"] },
+            "safety": { "enum": ["safe", "privileged", "sensitive", "diagnostic-only"] },
+            "legacy_source": { "type": "string", "minLength": 1 }
+          },
+          "additionalProperties": true
+        },
+        { "type": "array" }
+      ]
+    },
+    "contributionList": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "required": ["id"],
+        "properties": {
+          "id": { "type": "string", "minLength": 1 },
+          "region": { "type": "string", "minLength": 1 },
+          "label": { "type": "string" },
+          "order": { "type": ["number", "integer", "string"] }
+        },
+        "additionalProperties": true
+      }
+    }
+  }
+}
@@ -0,0 +1,247 @@
+"""Plugin manifest schema sanity tests.
+
+Four independent guarantees:
+
+1. `schema/plugin.schema.json` is itself a well-formed JSON Schema
+   (Draft 2020-12) and accepts every in-tree `plugins/*/plugin.json`.
+2. Each in-tree manifest's `id` matches its parent directory name —
+   the loader assumes this and silent drift would break plugin
+   discovery.
+3. The `license` enum in the schema enforces AGPL-3.0-only for
+    contributed manifests.
+4. The schema accepts capability-pipelines.v1 manifest metadata so
+    native capability declarations stay first-class in tooling.
+"""
+
+from __future__ import annotations
+
+import ast
+import glob
+import json
+import re
+from pathlib import Path
+
+import jsonschema
+import pytest
+
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+SCHEMA_PATH = REPO_ROOT / "schema" / "plugin.schema.json"
+DOCS_SCHEMA_PATH = REPO_ROOT / "docs" / "plugin-manifest.schema.json"
+CONTRIBUTING_PATH = REPO_ROOT / "CONTRIBUTING.md"
+PLUGINS_GLOB = str(REPO_ROOT / "plugins" / "*" / "plugin.json")
+BACKEND_CAPABILITIES_PATH = REPO_ROOT / "plugins" / "__init__.py"
+FRONTEND_CAPABILITIES_PATH = REPO_ROOT / "static" / "capabilities.js"
+
+
+@pytest.fixture(scope="module")
+def schema() -> dict:
+    with SCHEMA_PATH.open() as f:
+        return json.load(f)
+
+
+@pytest.fixture(scope="module")
+def docs_schema() -> dict:
+    with DOCS_SCHEMA_PATH.open() as f:
+        return json.load(f)
+
+
+def test_schema_is_well_formed(schema: dict) -> None:
+    """The schema file must itself validate as a Draft 2020-12 schema."""
+    jsonschema.Draft202012Validator.check_schema(schema)
+
+
+def test_schema_contains_capability_contract(schema: dict) -> None:
+    """The published schema must keep capability-pipelines.v1 fields first-class."""
+    assert schema["properties"]["standards"]["items"]["type"] == "string"
+    assert schema["properties"]["capabilities"]["additionalProperties"]["$ref"] == "#/$defs/capabilityDeclaration"
+    declaration = schema["$defs"]["capabilityDeclaration"]
+    assert "owner" in declaration["properties"]["roles"]["items"]["enum"]
+    assert "provider-coordinator" in declaration["properties"]["kind"]["enum"]
+    assert declaration["properties"]["operations"]["items"]["type"] == "string"
+    assert declaration["properties"]["requests"]["items"]["type"] == "string"
+    assert declaration["properties"]["observes"]["items"]["type"] == "string"
+    assert "exclusive-owner" in declaration["properties"]["ownership"]["enum"]
+    assert "diagnostic-only" in declaration["properties"]["safety"]["enum"]
+    assert "styles" in schema["properties"]
+    assert schema["properties"]["styles"]["pattern"].startswith("^assets/")
+    assert "pluginRelpath" in schema["$defs"]
+
+
+def test_docs_schema_capability_contract_matches_ci_schema(schema: dict, docs_schema: dict) -> None:
+    """The docs copy and CI schema must not drift on capability vocabulary."""
+    def without_descriptions(value):
+        if isinstance(value, dict):
+            return {key: without_descriptions(item) for key, item in value.items() if key != "description"}
+        if isinstance(value, list):
+            return [without_descriptions(item) for item in value]
+        return value
+
+    for key in ("standards", "capability_api", "capabilities", "ui", "ui_contributions", "runtime_domains", "domains", "settings_schema", "styles", "screen", "script", "routes", "tour", "settings"):
+        assert without_descriptions(docs_schema["properties"][key]) == without_descriptions(schema["properties"][key])
+    assert without_descriptions(docs_schema["$defs"]["pluginRelpath"]) == without_descriptions(schema["$defs"]["pluginRelpath"])
+    assert without_descriptions(docs_schema["$defs"]["domainName"]) == without_descriptions(schema["$defs"]["domainName"])
+    assert without_descriptions(docs_schema["$defs"]["capabilityDeclaration"]) == without_descriptions(schema["$defs"]["capabilityDeclaration"])
+    assert without_descriptions(docs_schema["$defs"]["domainDeclaration"]) == without_descriptions(schema["$defs"]["domainDeclaration"])
+    assert without_descriptions(docs_schema["$defs"]["contributionList"]) == without_descriptions(schema["$defs"]["contributionList"])
+
+
+def _python_constant_set(name: str) -> set[str]:
+    module = ast.parse(BACKEND_CAPABILITIES_PATH.read_text(encoding="utf-8"))
+    for node in module.body:
+        if isinstance(node, ast.Assign) and any(isinstance(target, ast.Name) and target.id == name for target in node.targets):
+            value = ast.literal_eval(node.value)
+            return set(value)
+    pytest.fail(f"Backend capability constant {name} not found")
+
+
+def _frontend_constant_set(name: str) -> set[str]:
+    text = FRONTEND_CAPABILITIES_PATH.read_text(encoding="utf-8")
+    match = re.search(rf"const\s+{re.escape(name)}\s*=\s*new\s+Set\(\s*\[(.*?)\]\s*\)", text, re.S)
+    if not match:
+        pytest.fail(f"Frontend capability constant {name} not found")
+    return set(re.findall(r"['\"]([^'\"]+)['\"]", match.group(1)))
+
+
+def test_capability_schema_vocabulary_matches_runtime_constants(schema: dict) -> None:
+    """Schema enums should evolve with backend and frontend capability validators."""
+    declaration = schema["$defs"]["capabilityDeclaration"]["properties"]
+    checks = [
+        (set(declaration["roles"]["items"]["enum"]), "_VALID_CAPABILITY_ROLES", "VALID_ROLES"),
+        (set(declaration["mode"]["enum"]), "_VALID_CAPABILITY_MODES", "VALID_MODES"),
+        (set(declaration["compatibility"]["enum"]), "_VALID_CAPABILITY_COMPATIBILITY", "VALID_COMPATIBILITY"),
+        (set(declaration["ownership"]["enum"]), "_VALID_CAPABILITY_OWNERSHIP", "VALID_OWNERSHIP"),
+        (set(declaration["kind"]["enum"]), "_VALID_CAPABILITY_KINDS", "VALID_DOMAIN_KINDS"),
+        (set(declaration["safety"]["enum"]), "_VALID_CAPABILITY_SAFETY", "VALID_SAFETY"),
+    ]
+    for schema_values, backend_name, frontend_name in checks:
+        assert schema_values == _python_constant_set(backend_name)
+        assert schema_values == _frontend_constant_set(frontend_name)
+
+
+@pytest.mark.parametrize("manifest_path", sorted(glob.glob(PLUGINS_GLOB)))
+def test_in_tree_manifest_validates(manifest_path: str, schema: dict) -> None:
+    """Every plugin.json under plugins/ must pass schema validation."""
+    with open(manifest_path) as f:
+        manifest = json.load(f)
+    jsonschema.validate(manifest, schema)
+
+
+@pytest.mark.parametrize("manifest_path", sorted(glob.glob(PLUGINS_GLOB)))
+def test_in_tree_manifest_id_matches_directory(manifest_path: str) -> None:
+    """The `id` field must match the parent directory name."""
+    with open(manifest_path) as f:
+        manifest = json.load(f)
+    expected = Path(manifest_path).parent.name
+    assert manifest["id"] == expected, (
+        f"Plugin id {manifest['id']!r} in {manifest_path} does not match "
+        f"directory name {expected!r}. The loader keys plugin lookup by "
+        f"directory; drift would silently break discovery."
+    )
+
+
+def test_capability_manifest_metadata_validates(schema: dict) -> None:
+    """Capability-declared manifests should validate alongside runtime loader fields."""
+    manifest = {
+        "id": "capability_example",
+        "name": "Capability Example",
+        "version": "0.1.0",
+        "license": "AGPL-3.0-only",
+        "standards": ["capability-pipelines.v1", "plugin-runtime-idempotent.v1"],
+        "script": "screen.js",
+        "settings": {"html": "settings.html"},
+        "settings_schema": {
+            "schema_version": "1",
+            "packable_keys": ["enabled"],
+        },
+        "ui": {
+            "settings": [{"id": "capability-example-settings", "region": "plugin-settings", "label": "Capability Example"}],
+        },
+        "capabilities": {
+            "library": {
+                "roles": ["provider"],
+                "kind": "provider-coordinator",
+                "operations": ["query-page", "query-artists", "query-stats"],
+                "description": "Provides a browsable library source.",
+                "mode": "active",
+                "compatibility": "none",
+                "ownership": "multi-provider",
+                "safety": "safe",
+                "version": 1,
+            },
+            "playback": {
+                "roles": ["observer"],
+                "observes": ["ready", "stopped"],
+                "mode": "active",
+                "compatibility": "none",
+                "ownership": "observer-only",
+                "safety": "safe",
+                "version": 1,
+            },
+        },
+    }
+    jsonschema.validate(manifest, schema)
+
+
+def test_current_capability_and_styles_manifests_validate(schema: dict) -> None:
+    """Validate real manifests that exercise the capability and styles surfaces."""
+    for relpath in [
+        "plugins/capability_inspector/plugin.json",
+        "plugins/highway_3d/plugin.json",
+    ]:
+        with (REPO_ROOT / relpath).open() as f:
+            jsonschema.validate(json.load(f), schema)
+
+
+def test_invalid_capability_metadata_fails_schema(schema: dict) -> None:
+    """Schema validation should still catch malformed native declarations."""
+    manifest = {
+        "id": "bad_capability_example",
+        "name": "Bad Capability Example",
+        "standards": ["capability-pipelines.v1"],
+        "capabilities": {
+            "library": {
+                "roles": ["admin"],
+                "mode": "active",
+                "compatibility": "none",
+                "safety": "safe",
+                "version": 1,
+            },
+        },
+    }
+    with pytest.raises(jsonschema.ValidationError):
+        jsonschema.validate(manifest, schema)
+
+
+def test_schema_license_enum_requires_agpl_only(schema: dict) -> None:
+    """Contributed manifests must not validate with non-AGPL licenses."""
+    assert schema["properties"]["license"]["enum"] == ["AGPL-3.0-only"]
+
+    manifest = {"id": "license_example", "name": "License Example", "license": "MIT"}
+    with pytest.raises(jsonschema.ValidationError):
+        jsonschema.validate(manifest, schema)
+
+
+def test_plugin_runtime_paths_are_plugin_relative(schema: dict) -> None:
+    """Runtime file path fields must reject escapes and URL suffixes."""
+    valid = {
+        "id": "path_example",
+        "name": "Path Example",
+        "screen": "screen.html",
+        "script": "assets/screen.js",
+        "routes": "routes.py",
+        "tour": "tours/intro.json",
+        "settings": {"html": "settings/settings.html"},
+    }
+    jsonschema.validate(valid, schema)
+
+    for field in ("screen", "script", "routes", "tour"):
+        for bad_path in ("../escape.html", "safe/../escape.html", "/abs.html", "C:/abs.html", "dir\\file.js", "screen.html?x=1", "screen.html#frag", "./screen.html", ".hidden"):
+            manifest = {"id": "bad_path_example", "name": "Bad Path Example", field: bad_path}
+            with pytest.raises(jsonschema.ValidationError):
+                jsonschema.validate(manifest, schema)
+
+    for bad_path in ("../settings.html", "settings/../settings.html", "/settings.html", "settings\\settings.html", "settings.html?x=1", "settings.html#frag", "./settings.html", ".settings.html"):
+        manifest = {"id": "bad_settings_path", "name": "Bad Settings Path", "settings": {"html": bad_path}}
+        with pytest.raises(jsonschema.ValidationError):
+            jsonschema.validate(manifest, schema)
Author	SHA1	Message	Date
Bret Mogilefsky	8a0fc424cd	redact: replace psarc/Rocksmith/official DLC references with neutral terms	2026-06-18 00:48:09 -07:00
barlindandBret Mogilefsky	9a07ebc3d5	docs: clarify plugin licensing and metadata access Signed-off-by: barlind <tobias@barlind.se>	2026-06-18 00:41:59 -07:00
barlindandBret Mogilefsky	04db4a233b	chore: address plugin manifest review Signed-off-by: barlind <tobias@barlind.se>	2026-06-18 00:41:56 -07:00
barlindandBret Mogilefsky	e76927524a	docs: amend constitution for capability-first plugins Signed-off-by: barlind <tobias@barlind.se>	2026-06-18 00:41:10 -07:00
barlindandBret Mogilefsky	4d046b666d	chore: address pre-PR review findings Signed-off-by: barlind <tobias@barlind.se>	2026-06-18 00:40:43 -07:00
barlindandBret Mogilefsky	35863b8886	docs: assume plugin capabilities by default Signed-off-by: barlind <tobias@barlind.se>	2026-06-18 00:40:39 -07:00
barlindandBret Mogilefsky	7d0021d04a	docs: make plugin guidance capability-first Signed-off-by: barlind <tobias@barlind.se>	2026-06-18 00:40:35 -07:00
barlindandBret Mogilefsky	26dba55d7e	chore: update PR 332 tooling for capability model	2026-06-18 00:40:12 -07:00
Miguel_LZPFandBret Mogilefsky	b45751164f	fix: address PR #332 review feedback Addresses 12 of 13 review comments from Copilot and CodeRabbit on PR #332. One comment (no-manifests in validate-plugins.yml) is declined and answered inline; the rest are applied here. Substantive fixes: - .github/workflows/validate-plugins.yml — add --noconftest to the schema-tests step. tests/conftest.py imports structlog at module level, but the CI job only installs requirements-test.txt (pytest/httpx/jsonschema), so pytest collection would fail at conftest import. The schema tests don't use shared fixtures, so skipping conftest is safe and avoids dragging the full runtime requirements into a 2 KB validation job. (Copilot) - schema/plugin.schema.json — tighten the server_files regex on both settings.server_files and diagnostics.server_files to match the runtime _validate_relpath rules in plugins/__init__.py. The previous regex only blocked absolute paths, drive letters, backslashes, and "..". The runtime also rejects "//", "./", "/./", and leading-dotfile segments. Schema-valid manifests are now also load-time-valid. Verified the regex against 12 cases: the 3 in-tree manifests still validate. (Copilot) - .claude/skills/plugin-validate/SKILL.md — add a per-iteration plugin_ok flag so we no longer print "OK <path>" after an earlier FAIL in the same manifest. Schema-pass + id-mismatch previously produced both FAIL and OK lines for one plugin. (CodeRabbit) - docs/websocket-protocol.md — clarify song_info.tuning array length is source-dependent (typically 6 guitar, 4 bass, but extended-range GP imports can be 7/8/5/6). Recommend highway.getStringCount() for the authoritative count. Line 30 already said this; the table row on line 12 was the stale half. (CodeRabbit) Trivial fixes: - .claude/rules/plugin-author.md — "wants included" -> "wants to include" in the settings.server_files rule. (CodeRabbit) - Markdown MD040 — add `text` language tags to 7 bare-fence code blocks across AGENTS.md, docs/PLUGIN_AUTHORING.md, docs/testing-plugins.md, docs/plugin-logging.md, .claude/README.md, .claude/agents/slopsmith-reviewer.md, and .claude/skills/plugin-validate/SKILL.md (two fences). (CodeRabbit) Declined: - .github/workflows/validate-plugins.yml no-manifests -> exit 0 (CodeRabbit suggested exit 1). Plugins in this repo are in-tree, not submodules (no .gitmodules, git submodule status empty), and the workflow has a path filter on plugins/*/plugin.json so it only runs when a manifest actually changes. Exit 0 is correct. Answered inline on the PR. Verification: pytest tests/test_plugin_schema.py -v --noconftest # 8 passed python -c "import json,glob,jsonschema; s=json.load(open('schema/plugin.schema.json')); [jsonschema.validate(json.load(open(p)), s) for p in sorted(glob.glob('plugins//plugin.json'))]" # ok — all 3 in-tree manifests validate against tightened schema Signed-off-by: Miguel_LZPF <mgcdreamer@gmail.com>	2026-06-18 00:38:51 -07:00
Miguel_LZPFandBret Mogilefsky	e4187d0054	feat: add cross-tool orientation, CI schema validation, and Claude Code surfaces Adds the contributor- and AI-tool-facing infrastructure on top of the modular docs from the previous commit. Lands AGENTS.md as the canonical cross-tool orientation (read natively by Cursor, Copilot, Codex, Aider, Cline, Continue, Cody, Devin, Replit Agent, and Claude Code), flips CLAUDE.md to a 22-line pointer that uses Claude Code's @-import to inline AGENTS.md, wires up plugin.json validation in CI, and adds the Claude-specific automation surfaces under .claude/. Cross-tool orientation: AGENTS.md (178 lines) — single source of truth: architecture, running the app, testing, git workflow, versioning, song formats, frontend and backend conventions, plugin authoring index, first-hour pitfalls, verification, house rules. CLAUDE.md (22 lines) — Claude Code memory file. Uses @AGENTS.md import (recursion depth 5) so the canonical content is inlined without duplication. Lists .claude/ surfaces. .github/copilot-instructions.md — Copilot custom instructions format; points at AGENTS.md and docs/PLUGIN_AUTHORING.md. .cursorrules — not added. Cursor reads AGENTS.md natively in 2026 and .cursorrules is legacy. Contribution hygiene (.github/): PULL_REQUEST_TEMPLATE.md — summary, linked issue, test plan, DCO and conventional-commit reminders. No AI-disclosure section. ISSUE_TEMPLATE/bug.yml — version, deployment, OS, plugins enabled, repro, logs (linked to docs/diagnostics-bundle-spec.md for redaction guidance). ISSUE_TEMPLATE/feature.yml — problem, proposed, alternatives, surface, plugin-author impact, license check. ISSUE_TEMPLATE/config.yml — disables blank issues; redirects plugin issues to plugin repos and security to the private advisory flow. CI: .github/workflows/validate-plugins.yml — runs on changes to plugins/, schema/, CONTRIBUTING.md, the test file, or the workflow itself. Installs jsonschema and pytest, validates every plugins//plugin.json against schema/plugin.schema.json, and runs the license-allowlist subset check. tests/test_plugin_schema.py — 8 parametrized tests: schema is well-formed, the 3 in-tree manifests validate, manifest id matches its parent directory name, schema license enum is a subset of CONTRIBUTING's curated allowlist. requirements-test.txt — append jsonschema>=4.0. .github/workflows/sync-version.yml — comment retargeted to AGENTS.md "Versioning" section. Claude Code surfaces (.claude/): README.md — layout explanation. Spec-kit owns skills/speckit-; repo-specific skills sit alongside. Hooks off by default; settings.json carries a commented opt-in example. skills/plugin-scaffold/SKILL.md — generates a plugin skeleton for type in {visualization, overlay, settings-only, routes-only}. skills/plugin-validate/SKILL.md — local pre-push check: validates plugin.json against schema, asserts declared files exist, enforces license allowlist. rules/plugin-author.md — globs scoped to plugins/. Encodes the contracts from docs/PLUGIN_AUTHORING.md so AI suggestions don't drift from them (manifest required, context[\"log\"] over print, load_sibling over bare imports, playSong await discipline, settings.server_files conventions). agents/slopsmith-reviewer.md — plugin-aware reviewer subagent; invoke with @slopsmith-reviewer. 12-item checklist mirrors the rule and the schema. settings.json — empty hooks block plus a commented PostToolUse example for opt-in plugin.json validation on save. Inbound-ref updates (files we own): README.md — \"AI Agent Guide\" points at AGENTS.md and notes .claude/ and copilot-instructions are tool-specific. CONTRIBUTING.md — \"Plugin System in CLAUDE.md\" -> docs/ and schema/; \"Git Workflow\" -> AGENTS.md#git-workflow. docs/sloppak-spec.md — plugin-system table cell -> docs/. Out of scope (intentionally untouched): plugins/highway_3d/README.md (gitlink — plugin owns its docs). .specify/memory/constitution.md and other spec-kit artefacts (spec-kit owns that surface; CLAUDE.md still resolves transitively via the @-import). Verification: pytest -q # backend + schema tests pass python -c \"import json,glob,jsonschema; s=json.load(open('schema/plugin.schema.json')); [jsonschema.validate(json.load(open(p)), s) for p in sorted(glob.glob('plugins//plugin.json'))]\" Signed-off-by: Miguel_LZPF <mgcdreamer@gmail.com>	2026-06-18 00:38:51 -07:00
Miguel_LZPFandBret Mogilefsky	1214a6c0a0	docs: extract plugin contracts into modular docs and slim CLAUDE.md CLAUDE.md had grown to 545 lines / 50 KB — most of it plugin-author content that other AI tools (Cursor, Copilot, Codex, Aider) and humans without AI never reach. Extract the plugin surface into 10 focused docs and a JSON Schema for plugin.json, then slim CLAUDE.md to a 156-line navigable index. New docs (~999 lines total, all self-contained): docs/PLUGIN_AUTHORING.md — entry point and quickstart docs/plugin-manifest.md — plugin.json field reference docs/plugin-visualization-contracts.md — setRenderer / overlay / note-state docs/plugin-audio-mixer.md — fader registration docs/plugin-logging.md — context["log"] + env vars docs/plugin-diagnostics.md — server_files / callable docs/plugin-keyboard-shortcuts.md — registerShortcut + scopes docs/plugin-sibling-imports.md — load_sibling pattern docs/websocket-protocol.md — /ws/highway message reference docs/testing-plugins.md — pytest fixtures + Playwright schema/plugin.schema.json — Draft 2020-12 schema for plugin.json; license enum mirrors CONTRIBUTING's curated allowlist. Backs CI validation and the plugin-validate skill. CLAUDE.md slim (581 lines changed, -485): - Removed ~300 lines of plugin-author prose (now in docs/). - Kept architecture quick reference, running the app, testing, git workflow, versioning, song formats, frontend/backend conventions, plugin authoring INDEX (table → docs/), first-hour pitfalls, "For AI agents" footer. - Anchor stubs preserved next to the new index entries so deep links from specs/001-slopsmith-platform/analyze.md still resolve. Verification: python -c "import json,glob,jsonschema; s=json.load(open('schema/plugin.schema.json')); [jsonschema.validate(json.load(open(p)), s) for p in sorted(glob.glob('plugins/*/plugin.json'))]" # ok — validates highway_3d, app_tour_library, app_tour_settings Signed-off-by: Miguel_LZPF <mgcdreamer@gmail.com>	2026-06-18 00:38:50 -07:00