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LiveKit/Agents JS/@livekit/agents@1.4.5

Tool calls no longer dropped in child sessions; realtime multi-message fixed

@livekit/agents@1.4.5

June 2, 2026Agents JSView original ↗
4 features3 enhancements14 fixesThis release4 featuresNew capabilities3 enhancementsImprovements to existing features14 fixesBug fixesAI-tallied from the release notes

Patch Changes

  • Fix AgentActivity.generateReply defaulting toolChoice to 'none' on a child AgentSession spawned inside a tool. The previous check relied on AsyncLocalStorage, which leaks the parent function-call context into the child session and caused the framework to drop legitimate tool calls emitted by the child agent (e.g. the supervisor's connect_to_caller invocation in WarmTransferTask). The check now uses per-task info, matching the Python implementation. - #1458 (@rosetta-livekit-bot)

  • Block user turn exceeded callbacks while an agent handoff is starting. - #1614 (@rosetta-livekit-bot)

  • fix: repair leaked chat-template tokens in function call args - #1604 (@rosetta-livekit-bot)

  • Fix interrupt race that could leak unplayed transcript text. - #1573 (@rosetta-livekit-bot)

  • Wire internal debug messages through remote sessions. - #1645 (@rosetta-livekit-bot)

  • subscribe to tracks published after connect with AUDIO_ONLY/VIDEO_ONLY - #1629 (@toubatbrian)

  • chore(worker): update worker warnings - #1571 (@rosetta-livekit-bot)

  • fix(inference): stop mislabeling barge-in handler errors as parse failures - #1619 (@chenghao-mou)

    The interruption WebSocket handler wrapped both wsMessageSchema.parse and handleMessage in one try, so a handler throw (e.g. a late bargein_detected prediction enqueued after the readable side was errored/closed) was logged as "Failed to parse WebSocket message" with the real error discarded. Parse and handler errors are now caught separately and log the actual error, and the late barge-in event is dropped quietly (desiredSize === null) instead of throwing into a dead stream.

  • update rtc sdk to 0.13.29 - #1652 (@davidzhao)

  • fix(llm): convert per-turn instructions on the first turn for Google provider format - #1589 (@rosetta-livekit-bot)

  • fix(realtime): process all messages in multi-message realtime generations - #1628 (@tinalenguyen)

    Reorders audio/text forwarding setup inside processOneMessage to match the Python source order (audio first, then text), and tightens the playout-await guard so playoutPromise is only awaited when not interrupted. This fixes a case where the second message in a multi-message realtime response (e.g. gpt-realtime-2 preambles) could be dropped.

    Also stamps assistant ChatMessage.createdAt with startedSpeakingAt (the first frame's playback start) instead of defaulting to Date.now() at end-of-generation. This preserves correct user/assistant ordering in ChatContext when user transcription items land during agent playout.

  • feat(realtime): support multi-message generation per response - #1555 (@rosetta-livekit-bot)

  • Prevent recorder close from hanging during encode cleanup and clamp recorder frame splits to valid frame bounds. - #1684 (@rosetta-livekit-bot)

  • Remove the ttsPronunciationMap Agent option (and the TTSPronunciationMap type). Use the general tts_text_transforms / replace text transform for pre-TTS pronunciation replacements instead. - #1620 (@u9g)

  • fix: reset user turn tracker when clearing user turn - #1615 (@rosetta-livekit-bot)

  • fix(voice): make ParticipantAudioOutput.pause() actually gate audio (port _playback_enabled + synchronizer pause) - #1579 (@toubatbrian)

  • Replace discarded input audio with silence for STT and realtime model streams. - #1601 (@rosetta-livekit-bot)

  • fix: make non-transient 4xx API status errors non-retryable - #1597 (@rosetta-livekit-bot)

  • feat: allow updating dynamic endpointing alpha on active sessions - #1634 (@rosetta-livekit-bot)

  • feat(google): add Vertex AI Model Garden LLM integration - #1606 (@rosetta-livekit-bot)

  • Add Soniox STT support and surface per-run source and target language segments on STT speech data. - #1602 (@rosetta-livekit-bot)

  • fix(llm): sort function tools to keep tool order invariant. - #1641 (@rosetta-livekit-bot)

  • Update download-files deprecation message - #1621 (@rosetta-livekit-bot)

  • Use STT transcript timestamps for last speaking time when VAD is unavailable or misses speech. - #1603 (@rosetta-livekit-bot)

  • fix(voice): surface tool-argument validation errors to the LLM instead of returning a generic "internal error" - #1606 (@rosetta-livekit-bot)

    When an LLM-generated tool call failed JSON parsing or Zod schema validation, the framework returned "An internal error occurred" to the LLM, which left the model with no way to correct itself — causing it to loop on the same invalid call. Argument-validation failures are now wrapped in a ToolError whose message includes the tool name and the validator's diagnostic, so the LLM can fix its arguments.

    Behavior is unchanged for exceptions thrown from inside a tool's execute: regular Errors are still masked as "An internal error occurred" to avoid leaking server-side details, and ToolError continues to be the supported way to forward a custom message to the LLM.

  • Make ToolOptions.abortSignal required. The framework always provides an AbortSignal to tool execution, so the field is no longer optional. Tool authors can rely on abortSignal always being defined and drop defensive if (abortSignal) checks. - #1678 (@toubatbrian)

  • Reset active VAD streams on flush so STT end-of-speech can recover without recreating streams. STT end-of-speech now preserves the VAD-owned lastSpeakingTime instead of overwriting it, keeping the end-of-turn "no new speech" check reliable when VAD is active. - #1574 (@rosetta-livekit-bot)

  • Add beta WarmTransferTask workflow for SIP-based human handoffs. - #1458 (@rosetta-livekit-bot)

Fetched June 2, 2026