## Summary
This PR keeps app-server RPC request trace context alive for the full
lifetime of the work that request kicks off (e.g. for `thread/start`,
this is `app-server rpc handler -> tokio background task -> core op
submissions`). Previously we lose trace lineage once the request handler
returns or hands work off to background tasks.
This approach is especially relevant for `thread/start` and other RPC
handlers that run in a non-blocking way. In the near future we'll most
likely want to make all app-server handlers run in a non-blocking way by
default, and only queue operations that must operate in order (e.g.
thread RPCs per thread?), so we want to make sure tracing in app-server
just generally works.
Depends on https://github.com/openai/codex/pull/14300
**Before**
<img width="155" height="207" alt="image"
src="https://github.com/user-attachments/assets/c9487459-36f1-436c-beb7-fafeb40737af"
/>
**After**
<img width="299" height="337" alt="image"
src="https://github.com/user-attachments/assets/727392b2-d072-4427-9dc4-0502d8652dea"
/>
## What changed
- Keep request-scoped trace context around until we send the final
response or error, or the connection closes.
- Thread that trace context through detached `thread/start` work so
background startup stays attached to the originating request.
- Pass request trace context through to downstream core operations,
including:
- thread creation
- resume/fork flows
- turn submission
- review
- interrupt
- realtime conversation operations
- Add tracing tests that verify:
- remote W3C trace context is preserved for `thread/start`
- remote W3C trace context is preserved for `turn/start`
- downstream core spans stay under the originating request span
- request-scoped tracing state is cleaned up correctly
- Clean up shutdown behavior so detached background tasks and spawned
threads are drained before process exit.
## Description
This PR stops emitting legacy `codex/event/*` notifications from the
public app-server transports.
It's been a long time coming! app-server was still producing a raw
notification stream from core, alongside the typed app-server
notifications and server requests, for compatibility reasons. Now,
external clients should no longer be depending on those legacy
notifications, so this change removes them from the stdio and websocket
contract and updates the surrounding docs, examples, and tests to match.
### Caveat
I left the "in-process" version of app-server alone for now, since
`codex exec` was recently based on top of app-server via this in-process
form here: https://github.com/openai/codex/pull/14005
Seems like `codex exec` still consumes some legacy notifications
internally, so this branch only removes `codex/event/*` from app-server
over stdio and websockets.
## Follow-up
Once `codex exec` is fully migrated off `codex/event/*` notifications,
we'll be able to stop emitting them entirely entirely instead of just
filtering it at the external transport boundary.
This is a subset of PR #13636. See that PR for a full overview of the
architectural change.
This PR implements the in-process app server and modifies the
non-interactive "exec" entry point to use the app server.
---------
Co-authored-by: Felipe Coury <felipe.coury@gmail.com>
Owen Lin