## Summary
Add an explicit `user` or `developer` role to
`thread/realtime/appendText` and propagate it through the realtime input
queue into `conversation.item.create`. Older JSON clients that omit the
field continue to default to `user`.
This lets app-provided context such as memory retain developer authority
without bypassing app-server through a renderer-owned data channel. The
app-server schemas, API documentation, and focused protocol and
websocket coverage are updated with the new contract.
The Codex Apps consumer is tracked in
[openai/openai#1025261](https://github.com/openai/openai/pull/1025261).
## Summary
Adds a second realtime v2 function tool, `remain_silent`, so the
realtime model has an explicit non-speaking action when the
collaboration mode or latest context says it should not answer aloud.
This is stacked on #18597.
## Design
- Advertise `remain_silent` alongside `background_agent` in realtime v2
conversational sessions.
- Parse `remain_silent` function calls into a typed
`RealtimeEvent::NoopRequested` event.
- Have core answer that function call with an empty
`function_call_output` and deliberately avoid `response.create`, so no
follow-up realtime response is requested.
- Keep the event hidden from app-server/TUI surfaces; it is operational
plumbing, not user-visible conversation content.
## Summary
- wrap realtime startup context in
`<startup_context>...</startup_context>` tags
- prefix V2 mirrored user text and relayed backend text with `[USER]` /
`[BACKEND]`
- remove the V2 progress suffix and replace the final V2 handoff output
with a short completion acknowledgement while preserving the existing V1
wrapper
## Testing
- cargo test -p codex-api
realtime_v2_session_update_includes_background_agent_tool_and_handoff_output_item
-- --exact
- cargo test -p codex-app-server webrtc_v2_background_agent_
- cargo test -p codex-app-server webrtc_v2_text_input_is_
- cargo test -p codex-core conversation_user_text_turn_is_
- Add outputModality to thread/realtime/start and wire text/audio output
selection through app-server, core, API, and TUI.\n- Rename the realtime
transcript delta notification and add a separate transcript done
notification that forwards final text from item done without correlating
it with deltas.
Adds WebRTC startup to the experimental app-server
`thread/realtime/start` method with an optional transport enum. The
websocket path remains the default; WebRTC offers create the realtime
session through the shared start flow and emit the answer SDP via
`thread/realtime/sdp`.
---------
Co-authored-by: Codex <noreply@openai.com>
- prefix realtime handoff output with the agent final message label for
both realtime v1 and v2
- update realtime websocket and core expectations to match
## Stack Position
2/4. Built on top of #14828.
## Base
- #14828
## Unblocks
- #14829
- #14827
## Scope
- Port the realtime v2 wire parsing, session, app-server, and
conversation runtime behavior onto the split websocket-method base.
- Branch runtime behavior directly on the current realtime session kind
instead of parser-derived flow flags.
- Keep regression coverage in the existing e2e suites.
---------
Co-authored-by: Codex <noreply@openai.com>
## Stack Position
1/4. Base PR in the realtime stack.
## Base
- `main`
## Unblocks
- #14830
## Scope
- Split the realtime websocket request builders into `common`, `v1`, and
`v2` modules.
- Keep runtime behavior unchanged in this PR.
---------
Co-authored-by: Codex <noreply@openai.com>
Alex Gamble