The 1.4 Seconds That Weren't on Any Span

Short summary

A customer heard 1.4 seconds of silent audio in a voice agent, but APM traces showed everything was fine—because the hidden latency lived in unattributed handoffs between components (VAD to ASR), not within them. Voice agents fail not in the LLM call but in orchestration gaps, which are invisible to traditional APM and require explicit span instrumentation to measure. The fix is wrapping component handoffs in OpenTelemetry spans; the root cause was often a connection pool stall under concurrent load.

• •End-to-end latency includes invisible gaps between components; traditional APM only instruments work, not waiting
• •Voice agent failures occur in handoff orchestration (VAD→ASR→LLM→TTS), not inside component calls
• •Solution: wrap orchestration handoffs in explicit OpenTelemetry spans to measure and fix infrastructure bottlenecks

Generated with AI, which can make mistakes.