Implements a two-level abort controller design to support real-time
interruption when the user speaks while the agent is still responding:
sessionAbortController (session-scoped)
- Created once when startSession() is called
- Fired only by terminateSession() (user hangs up)
- Propagated into each turn via addEventListener
turnAbort (per-turn, stored as handle.currentTurnAbort)
- Created fresh at the start of each executeTurn() call
- Stored on the VoiceSessionHandle so injectMessage() can abort it
- When a new inject arrives while a turn is running, injectMessage()
calls turnAbort.abort() BEFORE enqueuing the new message
Interruption flow:
1. User speaks mid-response → LiveKit stops TTS playback (client-side)
2. STT utterance → POST voice/inject → injectMessage() fires
3. handle.currentTurnAbort.abort() called → sets aborted flag
4. for-await loop checks turnAbort.signal.aborted on next SDK event → break
5. catch block NOT reached (break ≠ exception) → no error event emitted
6. finally block saves partial text with "[中断]" suffix to history
7. New message dequeued → fresh executeTurn() starts immediately
Why no "Agent error" message plays to the user:
- break exits the for-await loop silently, not via exception
- The catch block's error-event emission is guarded by err?.name !== 'AbortError'
AND requires an actual exception; a plain break never enters catch
- Empty or partial responses are filtered by `if response:` in agent.py
Also update module-level JSDoc with full architecture explanation covering
the long-lived run loop design, two-level abort hierarchy, tenant context
injection pattern, and SDK session resume across turns.
Update agent.py module docstring to document voice session lifecycle and
interruption flow for future maintainers.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
hailin
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