fix(openai realtime): keep derived capabilities in sync with updateOptions

[rosetta-livekit-bot]

Ports livekit/agents#6943 to the JS OpenAI Realtime implementation.

Summary

• derive turn-taking and transcription capabilities from current model options
• keep independent per-session capabilities synchronized while preserving model/session isolation
• propagate model option updates to active sessions and preserve the source warning behavior
• add the three source regression tests and a minor changeset for the new public update/session capability APIs

Source diff coverage

Source diff coverage

Source file	Classification	Target coverage
livekit-plugins/livekit-plugins-openai/livekit/plugins/openai/realtime/realtime_model.py	Adapted	plugins/openai/src/realtime/realtime_model.ts; camelCase and JS OpenAI wire types are used for the shared capability derivation, model/session updateOptions, active-session propagation, warning, and per-session capability copy. agents/src/llm/realtime.ts adds the prerequisite default session capability getter that already exists in Python but was absent in JS.
tests/test_realtime/test_openai_realtime_model.py	Adapted	plugins/openai/src/realtime/realtime_model.test.ts; all three tests added by #6943 are ported to Vitest using the existing task stub instead of Python SimpleNamespace.

No source files were not applicable.

Validation

• pnpm test agents: 112 files passed, 1522 tests passed, 5 skipped
• env -u OPENAI_API_KEY pnpm test plugins/openai: 5 files passed, 2 skipped; 75 tests passed, 7 skipped
• pnpm test plugins/openai/src/realtime/realtime_model.test.ts: 50 tests passed
• pnpm build: 40 workspace tasks passed
• pnpm --filter @livekit/agents-plugin-openai build: passed
• changed-file ESLint: passed with two pre-existing warnings
• cue-cli: live OpenAI Realtime text turn passed after updateOptions disabled server turn taking; assistant framework event resolved in 812 ms

Package-wide lint was run for both touched packages. It remains blocked by existing repository formatting failures (184 findings in @livekit/agents, 15 in the OpenAI plugin) under the available Node 20/pnpm 9 environment; the repository declares pnpm 11, which requires Node 22 and cannot run here.

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Ported from livekit/agents#6943

Original PR description

Problem

capabilities.turn_detection and capabilities.user_transcription come from constructor options, but update_options changed those options and left the capabilities alone.
A model switched to create_response=False does client-side turn taking (#6642), and the stale capability still reports that the server owns the turn.
AgentActivity then refuses allow_interruptions=False, and _resolve_rt_turn_detection_enabled selects the wrong mode for endpointing and for realtime-session reuse across a handoff.
Turn detection is also per session, because session(turn_detection_disabled=True) switches it off for one session, but the only capabilities object was on the model.

Fix

One function now derives server-side turn taking, and both the constructor and update_options call it, so the two cannot drift apart again.
RealtimeSession keeps its own capabilities copy and updates it from its own update_options.
One session can now hand turn taking to the client while the model and its other sessions stay unchanged.
The function also carries the interrupt_response warning, which update_options did not give before.

The turn_detection_disabled branch in the session constructor has no unit test, because a real session opens a websocket in __init__.

[changeset-bot]

🦋 Changeset detected

Latest commit: 932a46e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 39 packages

Name	Type
@livekit/agents	Major
@livekit/agents-plugin-openai	Major
@livekit/agents-plugin-anam	Major
@livekit/agents-plugin-anthropic	Major
@livekit/agents-plugin-assemblyai	Major
@livekit/agents-plugin-azure	Major
@livekit/agents-plugin-baseten	Major
@livekit/agents-plugin-bey	Major
@livekit/agents-plugin-cartesia	Major
@livekit/agents-plugin-cerebras	Major
@livekit/agents-plugin-deepgram	Major
@livekit/agents-plugin-did	Major
@livekit/agents-plugin-elevenlabs	Major
@livekit/agents-plugin-fishaudio	Major
@livekit/agents-plugin-google	Major
@livekit/agents-plugin-hedra	Major
@livekit/agents-plugin-hume	Major
@livekit/agents-plugin-inworld	Major
@livekit/agents-plugin-krisp	Major
@livekit/agents-plugin-lemonslice	Major
@livekit/agents-plugin-liveavatar	Major
@livekit/agents-plugin-livekit	Major
@livekit/agents-plugin-minimax	Major
@livekit/agents-plugin-mistral	Major
@livekit/agents-plugin-mistralai	Major
@livekit/agents-plugin-neuphonic	Major
@livekit/agents-plugin-perplexity	Major
@livekit/agents-plugin-phonic	Major
@livekit/agents-plugin-protoface	Major
@livekit/agents-plugin-resemble	Major
@livekit/agents-plugin-rime	Major
@livekit/agents-plugin-runway	Major
@livekit/agents-plugin-sarvam	Major
@livekit/agents-plugin-silero	Major
@livekit/agents-plugin-soniox	Major
@livekit/agents-plugin-tavus	Major
@livekit/agents-plugins-test	Major
@livekit/agents-plugin-trugen	Major
@livekit/agents-plugin-xai	Major

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[devin-ai-integration]

Devin Review found 1 potential issue.

View 1 additional finding in Devin Review. (Configure)

[devin-ai-integration]

🟡 Model option updates overwrite per-session transcription config

updateOptions gates turnDetection behind options.turnDetection !== undefined when forwarding to sessions but forwards inputAudioTranscription unconditionally as this._options.inputAudioTranscription. Any model-level update, even one changing only voice, then resets every session's transcription setting and userTranscription capability to the model's value, discarding session-specific customization.

Suggested change

	session.updateOptions({
	...options,
	turnDetection:
	options.turnDetection !== undefined ? this._options.turnDetection : undefined,
	inputAudioTranscription: this._options.inputAudioTranscription,
	});
	session.updateOptions({
	...options,
	turnDetection:
	options.turnDetection !== undefined ? this._options.turnDetection : undefined,
	inputAudioTranscription:
	options.inputAudioTranscription !== undefined
	? this._options.inputAudioTranscription
	: undefined,
	});

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