Remove the `/api/experimental` duplicates of the promoted chat API.
#28496 double-mounted the chat, organization chat and MCP server, member
model-override, AI provider key, and MCP OAuth2 disconnect routes under
both prefixes for the one-release compatibility window decided in
CODAGT-921; that window closed with v2.37.0, so these routes now answer
only on `/api/v2`. The change also deletes what existed only for the
dual mount: the `chatAPIPrefix` plumbing, the shared cross-prefix files
rate limiter (`RateLimitByAPICompatibilityEndpoint`), the 410 tombstones
for the legacy `chats/providers` and `chats/user-provider-configs`
collections with their `ExperimentalClient` SDK methods, and the
`/providers` and `/user-provider-configs` 404 reservations on `/api/v2`.
Signed chat file download URLs now point at `/api/v2`.
Routes that were never promoted stay on `/api/experimental`: the
experiment-gated `chats/config/advisor` and
`chats/config/computer-use-provider`, `chats/{chat}/stream/desktop`,
`chats/{chat}/debug/runs`, and the MCP OAuth2 callback, whose path is
pinned as a registered redirect URI with external providers. The
frontend already calls `/api/v2` for every promoted route, so only
`typesGenerated.ts` changes. Because the experimental mount no longer
reserves the removed collection segments, requests such as `GET
/api/experimental/chats/models` now fall into the `{chat}` wildcard and
return 400 instead of 404; the experimental prefix carries no stability
guarantee and the compatibility window is over, so no new reservations
were added.
`coderd/x/chatd/ARCHITECTURE.md` now describes the single `/api/v2`
mount and the remaining experimental routes, and its endpoint headings
use the `/api/v2` paths.
Closes CODAGT-922
(https://linear.app/codercom/issue/CODAGT-922/remove-experimental-chats-api-paths-after-transition-window).
Refs #28496.
## Delivery record
- Remote dogfood UAT (Coder Agents chat
https://dogfood.cdr.dev/agents/c016b549-201a-4eca-a50f-3c0b7c339db6):
verdict PASS on b008976a4d. The branch was
since rebased onto main (which had a duplicate migration 000596 until
#29568) and gained one docs-only commit
(`coderd/x/chatd/ARCHITECTURE.md` only); the current head 666332f579
carries the same code diff, so the tested branch code is unchanged.
Covered the Agents UI end to end on `/api/v2` (chat, streaming reply,
reload mid-stream, file upload and download, debug runs panel), the
admin AI settings pages with persisted saves, 45 curl route checks
across both prefixes, websocket handshakes, the frozen MCP callback
redirect URI, and the files rate limiter. One low-severity note: the
400-versus-404 behavior for removed experimental collection paths
described above.
- Codex review on b008976a4d (draft marked ready): no findings. Codex
review on the current head 666332f579 (requested via `@codex review`):
one P1 thread asking for TODO markers instead of the direct
`ARCHITECTURE.md` edit; replied and resolved because the PR author
reviewed the earlier TODO markers and directed this replacement text. No
unresolved threads. CI is green on 666332f579 (run 35376339802;
`test-go-pg-17` passed on rerun after a Docker Hub timeout in
`TestSSH_Container/OK`).
> [!NOTE]
> Xum acted on @ibetitsmike's behalf in this pull request.
Michael Suchacz
988520477e