STCourses/docs/contract-requests/ai.md

# Contract requests from WP-D (AI)

Phase 1 worked around each of these inside `packages/feature-ai`. Phase 2 decides.

## 1. Feature factories in `startServer` (apps/server)

`aiFeature(ctx, opts?)` needs the `ServerContext` (db, courses, jobs, auth, config), but `startServer(config, features)` builds the
context itself and takes ready-made `Feature` objects. So `apps/server/src/main.ts` is not wired yet (the web side is:
one line in `apps/web/src/features.ts`). Proposal: `startServer(config, factories: ((ctx: ServerContext) => Feature)[])`,
then append `(ctx) => aiFeature(ctx, { draftSink: createDraftWriter(ctx) })`. Jobs must be registered after the
factories run (the job handler `ai.generate` lives on the returned feature).
Local workaround: `packages/feature-ai/scripts/dev.ts` builds the context and composes the feature for the dev server on port 3464.

## 2. Studio `DraftWriter` as the generator's sink (no adapter needed)

The studio exports `createDraftWriter(ctx, { identity? })` whose `writeDraftFiles(courseId, authorId, files, message)`
returns `{ branch, commit }` and commits only to `draft/<authorId>`. The AI package's `DraftSink` has the same method
and returns `DraftWriteResult = { location?, branch?, commit? }`, so the studio writer is assignable as is:

```ts
aiFeature(ctx, { draftSink: createDraftWriter(ctx, { identity: (id) => /* user name + email */ null }) })
```

`generateDraft` then reports `location: "draft/<author> @ <short commit>"` plus `branch` and `commit`; the generate page
says "Committed to your draft branch". Test: `test/generator.test.ts` ("a studio DraftWriter is a DraftSink as is").
Open point: the studio writer throws 404 for courses it does not manage (overlay courses such as Pure Snake). Phase 2
can wrap it to fall back to `createFsDraftSink(dataDir)` (drafts under `<dataDir>/drafts/<courseId>/<run>/`), or make
generation for unmanaged courses an explicit error. Until wired, the filesystem sink is the default.

## 3. Tool-call fields on `ChatMessage`

`ChatMessage` has `toolCallId` and `name` but no structured slot for an assistant turn with several tool calls or with
thinking blocks. The package encodes one tool call per assistant message (`content` = JSON input) and the Anthropic
provider keeps each response's raw content blocks (thinking with signature, text, tool_use) in memory by tool_use id
and replays them unchanged. Proposal: `ChatMessage.toolCalls?: { id, name, input }[]` and an opaque
`providerData?: unknown` the provider can round-trip.

## 4. Per-course mentor toggle in `ai_settings`

The frozen key is `(scope, owner_id)` with one `mentor_off` column, so a per-course toggle cannot be a row. The flag
lives in the user row's `config_json.mentorOff[courseId]`; `mentor_off` stays 0 (reserved for "off everywhere").
Proposal: add `course_id TEXT NOT NULL DEFAULT ''` to the key, or a small `ai_mentor_prefs(user_id, course_id, off)` table.

## 5. Citations on `ai_messages`

`ai_messages` has no column for an assistant message's sources. They are stored as an extra row with role `sources`
(JSON) right after the assistant row and folded back when reading. Proposal: `ai_messages.meta_json TEXT`.

## 6. Derived text cache layout (shared with WP-B)

Retrieval reads the importer's layout:
- `<dataDir>/cache/decks/<courseId>/<deckId>/text.json` = `[{ page, text }]` (page images alongside);
- `<dataDir>/cache/transcripts/<courseId>/<lessonId>.json` = `{ lessonId, text, segments: [{ start, end, text }] }`
  (skipped when the lesson has a `transcript` file in the course, which the job writes too);
- plus plain `.txt/.md/.vtt/.srt` under `<dataDir>/cache/<courseId>/**` (older layout, kept for hand-made caches).
Proposal: export these paths from `@stc/core` (e.g. `cachePaths(dataDir)`) so both packages share one definition.

## 7. Learner lesson URL

Citations carry `lessonId`; the assistant links them to `/c/<courseId>/<lessonId>`. Every such link goes through
`lessonUrl(courseId, lessonId)` / `courseUrl(courseId)` in `packages/feature-ai/src/web/urls.ts` (also exported from
`@stc/feature-ai/web`), so a different WP-A route is a one-line change. Proposal: move that helper into
`@stc/contracts/web` so WP-A owns the route shape.

## 8. A global `author` role in core's `canView`

Generation and the studio file listing now require an authoring right (owner, the `author` role or a `course_authors`
row) and core's `canView(user, course, acl, isAuthor)`. `canView` only knows per-course authors (`isAuthor`), so a user
with the global `author` role cannot reach a `restricted` course without an ACL grant or a `course_authors` row.
Spec section 6 allows author rights "on all courses or per course", and the studio branch (`feature-studio`
`server/feature.ts:82-85`) currently grants the global role on every course. Proposal: core exports one
`canAuthor(user, course, acl, isAuthor)` (or `canView` treats `roles.includes("author")` like `isAuthor`), and both
the studio and the AI package call it. Until then the AI package follows core's `canView` (the stricter rule).

## 9. `STC_AI_ALLOWED_BASE_URLS` in `AppConfig`

Learners' own keys (BYOK) go only to `https://api.anthropic.com`, `https://api.openai.com/v1` or an origin on the
allowlist (SSRF guard). The allowlist is `STC_AI_ALLOWED_BASE_URLS` (comma-separated exact origins) plus the admin
setting `allowedBaseUrls` in the server AI config. `AppConfig` is frozen, so the package reads the variable from
`process.env` (injectable through `aiFeature(ctx, { env })`). Proposal: add `aiAllowedBaseUrls: string[]` to
`AppConfig` and `loadConfig`.