perf: skip discarded trace payload construction

[rosetta-livekit-bot]

Ports livekit/agents#7155.

Avoid constructing GenAI input/output payloads when spans are not recording or content capture is disabled. Preserve non-content request, response, usage, and legacy trace attributes, and avoid telemetry-only response accumulation when content will be discarded.

Source diff coverage

• livekit-agents/livekit/agents/llm/llm.py: adapted to agents/src/llm/llm.ts. Snapshot span recording/content-capture state at llm_request start, skip eager request/output builders, and skip telemetry-only response accumulation. The target lacked Python's existing capture-state getter, so agents/src/telemetry/gen_ai.ts adds captureContentEnabled() and agents/etc/agents.api.md records the public API.
• livekit-agents/livekit/agents/voice/generation.py: adapted to agents/src/voice/generation.ts. Guard legacy chat/tool serialization on span recording and uninstrumented GenAI content builders on recording plus capture enablement.
• tests/test_llm_telemetry.py: adapted across agents/src/llm/llm.test.ts and agents/src/voice/generation_telemetry.test.ts to match target test organization. All source-added/modified cases are covered: cached-token/content attributes, capture toggles, disabled/nonrecording stream payload construction and accumulation, nonrecording llm_node serialization, and disabled-capture non-content attributes.
• Not applicable: none.

Validation

• pnpm test agents (2,514 passed, 5 skipped)
• pnpm build
• pnpm lint (passes with pre-existing repository warnings)
• pnpm format:check
• pnpm --filter @livekit/agents typecheck
• pnpm --filter @livekit/agents api:check

cue-cli runtime validation was attempted after the full build, but the configured LiveKit environment rejected worker authentication with HTTP 401, so no framework-event run could be completed.

A minor changeset is included for the new public genAI.captureContentEnabled() API.

---

Ported from livekit/agents#7155

Original PR description

Tracing builds large chat and GenAI payloads before OpenTelemetry decides to discard them. Check span recording and content capture first, while retaining legacy chat context, recorded content, and non-content metrics.

A 1,000-message sampled-out llm_node drops from 4.1 ms to 84 µs locally.

Addresses AGT-3452

Initial prompt and agent context

Model: GPT-5.6

can you investigate linear AGT 3452?

sounds good, let's fix that with a draft PR first.

[changeset-bot]

🦋 Changeset detected

Latest commit: 427337c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 38 packages

Name	Type
@livekit/agents	Minor
@livekit/agents-plugin-anam	Minor
@livekit/agents-plugin-anthropic	Minor
@livekit/agents-plugin-assemblyai	Minor
@livekit/agents-plugin-azure	Minor
@livekit/agents-plugin-baseten	Minor
@livekit/agents-plugin-bey	Minor
@livekit/agents-plugin-cartesia	Minor
@livekit/agents-plugin-cerebras	Minor
@livekit/agents-plugin-deepgram	Minor
@livekit/agents-plugin-did	Minor
@livekit/agents-plugin-elevenlabs	Minor
@livekit/agents-plugin-fishaudio	Minor
@livekit/agents-plugin-google	Minor
@livekit/agents-plugin-hume	Minor
@livekit/agents-plugin-inworld	Minor
@livekit/agents-plugin-krisp	Minor
@livekit/agents-plugin-lemonslice	Minor
@livekit/agents-plugin-liveavatar	Minor
@livekit/agents-plugin-livekit	Minor
@livekit/agents-plugin-minimax	Minor
@livekit/agents-plugin-mistral	Minor
@livekit/agents-plugin-mistralai	Minor
@livekit/agents-plugin-neuphonic	Minor
@livekit/agents-plugin-openai	Minor
@livekit/agents-plugin-perplexity	Minor
@livekit/agents-plugin-phonic	Minor
@livekit/agents-plugin-protoface	Minor
@livekit/agents-plugin-resemble	Minor
@livekit/agents-plugin-rime	Minor
@livekit/agents-plugin-runway	Minor
@livekit/agents-plugin-sarvam	Minor
@livekit/agents-plugin-silero	Minor
@livekit/agents-plugin-soniox	Minor
@livekit/agents-plugin-tavus	Minor
@livekit/agents-plugins-test	Minor
@livekit/agents-plugin-trugen	Minor
@livekit/agents-plugin-xai	Minor

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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.