# Extensions

Plugin system with three tiers: Browser JS (client-side), Starlark
sandbox (server-side, v0.29.0), Sidecar containers (server-side, future).

### User Extensions

**Auth:** Authenticated user

```
GET  /extensions                    → {"data": [...UserExtension]}
     ?tier=browser                  (optional filter by tier)
POST /extensions/:id/settings       ← {"is_enabled": bool, "settings": {...}}
     :id = extension UUID           → {"ok": true}
GET  /extensions/:id/manifest       → {"data": <manifest JSON>}
     :id = ext_id (manifest id)
GET  /extensions/tools              → {"data": [...tool schema objects]}
```

**Notes:**
- `GET /extensions` returns `UserExtension` objects: the base extension
  fields plus `user_enabled` and `user_settings` overrides.
- System extensions (`is_system: true`) cannot be disabled by users.
  Attempting to set `is_enabled: false` on a system extension returns 403.
- `GET /extensions/tools` returns raw tool schema JSON from all enabled
  browser extensions' `manifest.tools[]` arrays.

### Extension API Routes (v0.29.1)

Starlark packages serve custom JSON endpoints. Mounted at
`/s/:slug/api/*path` with JWT authentication.

**Auth:** Authenticated user (JWT — returns 401, not redirect)

```
ANY  /s/:slug/api/*path             → Starlark on_request(req) response
```

**Route:** `slug` is the package ID. `path` is matched against the
manifest's `api_routes` declaration.

**Manifest `api_routes` field:**

```json
{
  "api_routes": [
    {"method": "GET",  "path": "/status"},
    {"method": "POST", "path": "/webhook"},
    {"method": "*",    "path": "/proxy/*"}
  ]
}
```

- `method`: exact match (case-insensitive), or `"*"` for any method
- `path`: exact match, or trailing `"*"` for prefix match
- Boolean `true` shorthand: all routes forwarded
- Missing or `false`: no routes served

**Request dict passed to `on_request(req)`:**

```python
{
    "method":   "POST",
    "path":     "/webhook",
    "headers":  {"content-type": "application/json", ...},
    "query":    {"page": "1", ...},
    "body":     "{...}",
    "user_id":  "uuid"
}
```

**Expected return dict:**

```python
{"status": 200, "headers": {"X-Custom": "val"}, "body": "{...}"}
```

- `status`: int (default 200). Return `None` for 204 No Content.
- `headers`: dict (optional). Content-Type auto-detected if not set.
- `body`: string (default "").

**Validation pipeline:**
1. Package exists and is enabled
2. Status is `active` (not `pending_review` or `suspended`)
3. Tier is `starlark`
4. `api.http` permission is granted
5. Method+path matches `api_routes` in manifest

**Errors:**
- `401` — no/invalid JWT
- `403` — package suspended or missing `api.http` permission
- `404` — package not found, disabled, or route not declared
- `400` — package is not starlark tier
- `500` — Starlark execution error

### Admin Extension Management

**Auth:** Admin role

```
GET    /admin/extensions             → {"data": [...Extension]}
POST   /admin/extensions             ← {ext_id*, name*, version?, tier?,
                                        description?, author?, manifest?,
                                        is_system?, is_enabled?}
                                     → {"data": Extension} (201)
PUT    /admin/extensions/:id         ← {name?, version?, description?,
     :id = extension UUID               author?, is_system?, is_enabled?,
                                        manifest?}
                                     → {"data": Extension}
DELETE /admin/extensions/:id         → {"ok": true}
     :id = extension UUID
```

**Install defaults:** `version` → `"0.0.0"`, `tier` → `"browser"`,
`manifest` → `{}`, `scope` → `"global"`.

**Tier validation:** `tier` must be one of: `browser`, `starlark`, `sidecar`.

**Duplicate rejection:** If `ext_id` is already installed, returns 409.

### Asset Serving

**Auth:** None (public — script tags can't send Authorization headers)

```
GET /extensions/:id/assets/*path    → application/javascript
    :id = ext_id (manifest id)
```

Returns the inline `_script` field from the extension's manifest.
The `*path` segment is accepted but currently ignored (all requests
return the same script). Disabled extensions return 404.

### Extension Permissions (v0.29.0+)

Starlark packages declare capabilities in `manifest.permissions`.
Admin must grant each before the package activates.

| Permission | Module | Description |
|-----------|--------|-------------|
| `secrets.read` | `secrets` | Read extension secrets via GlobalConfig |
| `notifications.send` | `notifications` | Send in-app notifications |
| `filters.pre_completion` | — | Register pre-completion filter |
| `api.http` | `http` | Outbound HTTP requests (v0.29.0: module, v0.29.1: also required for API routes) |
| `provider.complete` | `provider` | LLM completion calls via BYOK chain (v0.29.1) |
| `db.read` | `db` | Read extension tables (future) |
| `db.write` | `db` | Write extension tables (future) |

### Starlark Modules (v0.29.0+)

Modules injected into the script namespace based on granted permissions:

**`secrets`** (requires `secrets.read`):
- `secrets.get(key)` → string or None
- `secrets.list()` → list of key names

**`notifications`** (requires `notifications.send`):
- `notifications.send(user_id, title, body?, type?)` → True

**`http`** (requires `api.http`, v0.29.1):
- `http.get(url, headers?)` → `{"status": int, "headers": dict, "body": string}`
- `http.post(url, body?, headers?)` → response dict
- `http.put(url, body?, headers?)` → response dict
- `http.delete(url, headers?)` → response dict
- `http.request(method, url, body?, headers?)` → response dict
- SSRF protection: private/loopback/link-local IPs blocked after DNS
- Manifest `network_access`: `{"allow": [...]}` or `{"block": [...]}`

**`provider`** (requires `provider.complete`, v0.29.1):
- `provider.complete(messages, model?, max_tokens?, temperature?)` → response dict
- Response: `{"content", "model", "finish_reason", "input_tokens", "output_tokens"}`
- Provider resolved via BYOK chain; pinnable via `requires_provider.provider_config_id`

### Builtin Seeding

On startup, `SeedBuiltinExtensions()` scans `extensions/builtin/`
for subdirectories containing `manifest.json` + `script.js`. Each
is upserted as a system extension:
- **New ext_id** → `Create` with `is_system: true`
- **Same version** → skip (idempotent)
- **Different version** → `Update` manifest, name, description, author

---