fix: Improve voice agent first reply latency#54
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| # Rename prewarm entries from the temporary key to the real call_sid | ||
| # so the rest of the pipeline (MCP check, twilio_stream, _end_session) | ||
| # can look up the session by call_sid as normal. | ||
| if prewarm_key in self._active_sessions: |
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Bug: race condition — prewarm session may not be re-keyed in time
_prewarm_audio_session runs concurrently and writes to _active_sessions[prewarm_key] only after its own await chain completes. This re-key check executes right after make_outbound_call() returns — with no synchronisation between the two. When the task has not yet registered the session, the check is False and _active_sessions[call_sid] is never populated.
When twilio_stream later calls _start_audio_session(call_sid), the session is not found, a second cold-start session is created, and the prewarmed session under prewarm_key is never cleaned up (leaking a live Gemini WebSocket connection).
Fix: eliminate the rename entirely — pass call_sid to _prewarm_audio_session only after make_outbound_call() returns (i.e. the two operations are still concurrent, but the task is created after call_sid is known and keyed directly under it).
| # answered before or after prewarm completes (prewarmed path ignores | ||
| # init_config in _start_audio_session). | ||
| effective_prompt = system_prompt or DEFAULT_SYSTEM_PROMPT | ||
| if context_messages: |
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Cleanup: context_messages → system_prompt merging is duplicated
The same '\n'.join(context_messages) + f-string pattern appears here (lines 701–703) and again in twilio_transport.py lines 159–162. Any change to the merge format (adding a header, escaping, trimming) must be applied in both places. Consider extracting a shared helper, e.g.:
def _build_effective_prompt(base: str, context_messages: list[str] | None) -> str:
if not context_messages:
return base
return f"{base}\n\nContext:\n{'\n'.join(context_messages)}"2 participants
closes #
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