Expose Cartesia STT turn detection options

[rosetta-livekit-bot]

Summary

• Exposes Cartesia ink-2 STT turn-detection thresholds and keyterm options on STTOptions.
• Sends the new options as /stt/turns/websocket query parameters, preserving repeated keyterm values.
• Rejects turn-detection-only options for legacy ink-whisper STT models.
• Adds a Cartesia changeset and API report metadata for the new public API.

Source diff coverage

Source file from livekit/agents#6594	Target coverage
livekit-plugins/livekit-plugins-cartesia/livekit/plugins/cartesia/_recognize_streams/auto_finalize_recognize_stream.py	Adapted to plugins/cartesia/src/stt.ts. The JS plugin keeps the turn-detecting websocket stream in the main STT file rather than a separate recognize-stream module, so the constructor/storage changes map to STTOptions and SpeechStream, and websocket query serialization maps to SpeechStream.#getCartesiaUrl().
livekit-plugins/livekit-plugins-cartesia/livekit/plugins/cartesia/stt.py	Ported to plugins/cartesia/src/stt.ts. Added public STT options, legacy-model validation, option storage/updates, and propagation to the turn-detecting websocket stream.
Tests	Not applicable. Source PR #6594 does not add or modify tests, so no target tests were added beyond running the existing Cartesia package tests.

Testing

• pnpm test plugins/cartesia
• pnpm --filter @livekit/agents-plugin-cartesia build
• pnpm --filter @livekit/agents-plugin-cartesia lint
• pnpm --filter @livekit/agents-plugin-cartesia api:check
• pnpm build
• pnpm lint (completed successfully; existing warnings are emitted in unrelated packages)

---

Ported from livekit/agents#6594

Original PR description

Sibling of #6587 (same pattern for xAI STT): exposes the turn-detection tuning parameters documented for Cartesia's /stt/turns/websocket (https://docs.cartesia.ai/api-reference/stt/turns/websocket) on cartesia.STT:

• turn_start_threshold (0.5–0.9, default 0.8) — likelihood above which a turn starts
• turn_eager_end_threshold (0.3–0.6, default 0.4) — likelihood below which turn.eager_end fires
• turn_end_threshold (0.05–0.5, default 0.2) — likelihood below which the turn ends
• turn_end_timeout_ms (640–11200, default 5600) — silence backstop for ending a turn
• keyterm (list, up to 100 terms / 1200 chars) — recall biasing; sent as repeated query params, so the turns-websocket params dict became a list of pairs

These are the primary tuning levers when running ink-2 with turn_detection="stt" in an AgentSession — today the plugin connects to the turns endpoint with no way to adjust them. All five are NotGivenOr and omitted when unset, so the default connection sends the identical query string as before. Passing any of them with a non-turn-detecting model (ink-whisper → the legacy endpoint) raises ValueError, mirroring the model-gated params in the AssemblyAI plugin.

Live-verified against wss://api.cartesia.ai/stt/turns/websocket (real key, today):

• in-range values (e.g. turn_start_threshold=0.85, repeated keyterm) → {"type":"connected", ...}
• out-of-range (turn_start_threshold=2.0) → error frame "turn_start_threshold must be between 0.5 and 0.9." + close — so the server parses and validates exactly these param names (unknown params are silently ignored, which is why the client-side ValueError guard is worth having)

Verified with ruff check / ruff format.

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: d6718ab

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-plugin-cartesia	Major
@livekit/agents	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-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-openai	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-plugin-trugen	Major
@livekit/agents-plugin-xai	Major
@livekit/agents-plugins-test	Major

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[u9g]

done in #2173