## Summary
Moves the messages response out of `GET /chats/{id}` and into a
dedicated `GET /chats/{id}/messages` endpoint.
### Backend
- `GET /chats/{id}` now returns just the `Chat` object (no messages)
- `GET /chats/{id}/messages` is a new endpoint returning
`ChatMessagesResponse` with `messages` and `queued_messages`
- Added `ChatMessagesResponse` SDK type and `GetChatMessages` client
method
### Frontend
- `getChat()` API method returns `Chat` instead of `ChatWithMessages`
- Added `getChatMessages()` API method for the new endpoint
- Split `chatQuery` into two: `chatQuery` (metadata) and
`chatMessagesQuery` (messages)
- Updated all cache mutations, optimistic updates, and websocket
handlers
- Updated tests and stories
### Files changed
| File | Change |
|---|---|
| `coderd/coderd.go` | Register `GET /messages` route |
| `coderd/chats.go` | Simplify `getChat`, add `getChatMessages` handler
|
| `codersdk/chats.go` | New type + method, update `GetChat` return |
| `site/src/api/api.ts` | New method, update `getChat` |
| `site/src/api/queries/chats.ts` | New query, update cache mutations |
| `site/src/pages/AgentsPage/AgentDetail.tsx` | Use separate queries |
| `site/src/pages/AgentsPage/AgentDetail/ChatContext.ts` | Update types
and cache writes |
| `site/src/pages/AgentsPage/AgentsPage.tsx` | Update websocket cache
handler |
Fixes Anthropic 400 error on multi-turn conversations with web search:
> web_search tool use with id srvtoolu_... was found without a
corresponding web_search_tool_result block
Provider-executed tool results (e.g. `web_search`) had a nil `Result`
field, which serialized as `"result":null`. Fantasy's
`UnmarshalToolResultOutputContent` couldn't deserialize `null` back, so
the entire assistant message became unreadable after persistence. On the
next LLM call, Anthropic rejected the conversation because
`server_tool_use` had no matching `web_search_tool_result`.
**Fix:** Bump the fantasy fork to e4bbc7bb3054 which returns `nil, nil`
for null `Result` JSON instead of erroring.
**Testing:** Added `integration_test.go` with
`TestAnthropicWebSearchRoundTrip` (requires `ANTHROPIC_API_KEY`) that:
- Sends a query triggering web search
- Verifies the persisted assistant message contains all parts the UI
needs: `tool-call(PE)`, `source`, `tool-result(PE)`, and `text`
- Sends a follow-up to confirm the round-trip works with Anthropic
Kyle Carberry