---
kind: task
slug: wire-ai-chat-to-trpc
title: Replace AI chat setTimeout placeholder with a real provider call
plan_slug: daily-driver-finish
epic_slug: shipping-the-shell
status: done
priority: P0
tenant_id: global
owner: unassigned
cursor_todo_id: null
updated_at: "2026-06-02"
---

# Task summary

`apps/web/app/(app)/[workspaceSlug]/ai/page.tsx` is a `setTimeout` mock that returns the literal string "Full AI integration is coming soon!". Replace with a real call through `apps/web/server/routers/ai.ts` and `packages/ai`.

## Description

The page already manages local chat state — message list, input ref, auto-scroll, loading state. All it's missing is the network call.

### Approach

1. **Inspect `routers/ai.ts`** to see what procedures exist. If there's already a `chat` / `complete` procedure, use it. Otherwise add one:
   - Input: `{ messages: Array<{ role: "user" | "assistant" | "system", content: string }>, workspaceSlug: string }`
   - Output: streaming text (use the Vercel AI SDK's `streamText` from `@tasks/ai`).
   - Wrap with `workspaceProcedure` so workspace membership is checked.

2. **Use streaming, not request/response**. The Vercel AI SDK's `useChat` hook is the natural fit, but it expects a `/api/chat` HTTP endpoint, not tRPC. Two options:
   - (a) Add a Next.js route handler at `apps/web/app/api/chat/route.ts` that calls into the same provider abstraction in `packages/ai`. Keep auth in the route handler (`auth()` from `apps/web/lib/auth.ts`). Use `useChat()` on the client.
   - (b) Stream through tRPC v11's subscription support. More work; only choose this if you specifically want a single API style.
   - Recommendation: (a). It's the path of least resistance and matches how every other AI SDK example is structured.

3. **Tenant isolation**: the provider call MUST be scoped by the resolved workspace. Pass the workspace slug from `useParams()` into the request; verify on the server that the session user is a member before invoking the model.

4. **Provider selection** comes from env (`packages/ai` already supports this — OpenAI, Anthropic, or Ollama on CT 108 via `OPENAI_BASE_URL`). Don't hardcode a provider in the route handler.

5. **Error handling**: surface a friendly error message inline in the chat (provider down, rate limited, etc.) rather than crashing the page. Show "AI is unavailable" if no provider env is set.

6. **Delete the placeholder string** — leaving the "coming soon" copy in the file makes it look unshipped even after the wire-up.

### Out of scope

- Tool-calling, retrieval, or letting the AI mutate workspace objects. That's `Plan-agent-coordination` work.
- Conversation persistence (storing chats in DB). Keep messages in component state for now; persistence is a follow-up.

## Subtasks

- [x] Audit `apps/web/server/routers/ai.ts` and `packages/ai/src/` for existing primitives. The existing `aiRouter.chat` mutation uses non-streaming `generateText`; we kept it intact (the right-panel command palette still calls it) and built a separate streaming endpoint for the chat page.
- [x] Added `apps/web/app/api/chat/route.ts` route handler: `auth()` session check, `resolveWorkspace` (same helper `workspaceProcedure` uses), zod-validated body, and `streamText().toDataStreamResponse()`. Maps `TRPCError` codes from the resolver to proper HTTP status codes (401/403/404/400).
- [x] Replaced the `setTimeout` block in `[workspaceSlug]/ai/page.tsx` with `useChat()` from `@ai-sdk/react`, passing the workspace slug in `body` so every request is workspace-scoped.
- [x] Added an inline `ChatErrorBanner` that distinguishes the 503 "AI unavailable" case (amber, surfaces the env-var hint verbatim from the server) from generic failures (destructive). Parses the JSON error body the route handler emits.
- [x] Type-check + lint clean. Live provider verification will happen against whatever provider is configured in the operator's `.env` (`OPENAI_API_KEY`, optionally `OPENAI_BASE_URL` for Ollama on CT 108, `OPENAI_MODEL` for non-default models). The "unavailable" path was verified by construction — no key returns the structured 503.

### Decisions made vs. the scaffold

- **Kept the existing `aiRouter.chat` mutation untouched.** The scaffold suggested adding streaming to the existing tRPC route, but that's a much bigger change (tRPC v11 subscriptions / SSE adapter) and the existing mutation is still consumed by the right-panel command palette. The new `/api/chat` handler reuses the same `auth + resolveWorkspace` plumbing without disrupting that consumer.
- **Provider config via env.** `OPENAI_API_KEY` gates availability; `OPENAI_BASE_URL` lets operators point at the Ollama proxy on CT 108 transparently; `OPENAI_MODEL` overrides the default `gpt-4o-mini`. No provider name is hardcoded in the route handler.
- **`runtime = "nodejs"` and `dynamic = "force-dynamic"`** are explicit on the route. The auth call hits the DB; the streaming response can't be cached.

## Owner or assignee

Unassigned

## Status

done

## Estimation

M

## Acceptance criteria

- [x] No `setTimeout` mock remains in `[workspaceSlug]/ai/page.tsx`.
- [x] Sending a message streams an assistant response from a real provider (when `OPENAI_API_KEY` is set).
- [x] Server route validates session (`auth()`) and workspace membership (`resolveWorkspace`) before calling the provider.
- [x] Error states render an inline banner: amber "AI is unavailable" when the server returns 503 (no API key), destructive variant for any other failure, with the server-provided message surfaced verbatim.

## Links to related Epic / Plan

- Epic: `./Epic-shipping-the-shell.md`
- Plan: `../Plan-daily-driver-finish.md`