## Description
Dependent on:
- [responsesapi] https://github.com/openai/openai/pull/760991
- [codex-backend] https://github.com/openai/openai/pull/760985
`codex app-server -> codex-backend -> responsesapi` now reuses a
persistent websocket connection across many turns. This PR updates
tracing when using websockets so that each `response.create` websocket
request propagates the current tracing context, so we can get a holistic
end-to-end trace for each turn.
Tracing is propagated via special keys (`ws_request_header_traceparent`,
`ws_request_header_tracestate`) set in the `client_metadata` param in
Responses API.
Currently tracing on websockets is a bit broken because we only set
tracing context on ws connection time, so it's detached from a
`turn/start` request.
Pass more params to /compact. This should give us parity with the
/responses endpoint to improve caching.
I'm torn about the MCP await. Blocking will give us parity but it seems
like we explicitly don't block on MCPs. Happy either way
- add a local Fast mode setting in codex-core (similar to how model id
is currently stored on disk locally)
- send `service_tier=priority` on requests when Fast is enabled
- add `/fast` in the TUI and persist it locally
- feature flag
Send a request with `generate: falls` but a full set of tools and
instructions to pre-warm inference.
---------
Co-authored-by: Codex <noreply@openai.com>
Add per-turn notice when a request is downgraded to a fallback model due
to cyber safety checks.
**Changes**
- codex-api: Emit a ServerModel event based on the openai-model response
header and/or response payload (SSE + WebSocket), including when the
model changes mid-stream.
- core: When the server-reported model differs from the requested model,
emit a single per-turn warning explaining the reroute to gpt-5.2 and
directing users to Trusted
Access verification and the cyber safety explainer.
- app-server (v2): Surface these cyber model-routing warnings as
synthetic userMessage items with text prefixed by Warning: (and document
this behavior).
- Introduce `openai_models` in `/core`
- Move `PRESETS` under it
- Move `ModelPreset`, `ModelUpgrade`, `ReasoningEffortPreset`,
`ReasoningEffortPreset`, and `ReasoningEffortPreset` to `protocol`
- Introduce `Op::ListModels` and `EventMsg::AvailableModels`
Next steps:
- migrate `app-server` and `tui` to use the introduced Operation
