feat(typescript-sdk): voice agent testing — consolidated clean stack

[drewdrewthis]

Why

Closes #372 (epic #370). The TypeScript voice-agent-testing port had fragmented into 10 flat-sibling PRs (#513/#515/#528/#534–540) carrying pre-EDR design drift. This replaces all of them with one clean stack rebuilt against main, conforming to the EDR (#560 / ADR-002) and the decided public API (PRD). Python is the reference implementation; this brings TS to parity.

Acceptance Criteria

The behavioral contract is specs/voice-agents.feature — 127 scenarios ported from the Python source-of-truth (79 @unit, 14 @integration, 39 @e2e, 2 @todo). Collapsed to the headline ACs below, each ticked only with evidence on this branch. "Done" = (1) the ci-checks gate (units + build + non-bot @ts-e2e) green, (2) the committed demo recordings present, and (3) the app-side ACs below (AC13–18) verified — a voice run correctly ingested, queryable, and rendered in the langwatch app. SDK-green alone is necessary but not sufficient.

Status legend: ✅ = evidence verified in-tree/observed · ⏳ = implemented + author-reported green locally, not yet confirmed by CI · ◻️ = open. (2026-06-04: the unit suite now runs in CI — ci-checks (24.x) green on run 26960103187 after the rebase + lockfile fix; formerly-⏳ unit-backed rows are CI-confirmed.)

Binding status: 29/127 scenarios carry @ts-bound (wired to an executable TS test). The remaining 98 are contract-level (ported from the Python spec), covered indirectly rather than by 1:1 bindings. The full suite is CI-confirmed at 796 pass / 1 skip on HEAD 390e52c (run 26960103187) — the former lockfile abort is fixed, so unit-backed ACs below are ✅ on real CI evidence. Demo-recording-backed ACs are ✅ (the 16 recordings are committed and present in-tree — verified).

#	Acceptance criterion	Evidence	Status
AC1	Same entrypoint — voice uses scenario.run(), text-only scenarios unaffected by voice deps	voice_text_parity recording (in-tree ✅) + unit "Existing text-only scenarios unaffected" (✅ CI)	✅
AC2	Per-run provider state (ADR-002) — voice config on ScenarioConfig.voice, no module-global configure()	composable_stt_swap recording (in-tree ✅); STT-swap units (✅ CI)	✅
AC3	Barge-in primitive — agent({ wait:false }) + interrupt() cuts off a reply mid-utterance, marked truncated	interruption_recovery recording, judge hard-gated (in-tree ✅)	✅
AC4	Real server-VAD barge-in on Gemini Live + ElevenLabs (mid-stream cut-off)	gemini_live_interruption + elevenlabs_interruption recordings (in-tree ✅)	✅
AC5	Adapter parity — OpenAI Realtime (agent+user), ElevenLabs (hosted/branded/composable), Gemini Live, Pipecat	openai_realtime_{agent,user}, elevenlabs_{hosted,branded}, gemini_live, pipecat_{scenario,ws} recordings (in-tree ✅)	✅
AC6	Audio effects + tonal realism — noise floor, distortion, audible anger	angry_customer recording, noise-floor≫silence assertion (in-tree ✅)	✅
AC7	Voice-aware judge — auto-detects audio, transcript fallback for non-multimodal, structured timeline	@ts-judge 7-scenario unit suite — CI-confirmed (run 26960103187)	✅
AC8	Capability matrix is a contract — every adapter publishes capabilities; dtmf() raises UnsupportedCapabilityError off-telephony; matrix in docs	@ts-contract-surface units (✅ CI) + adapters/*.mdx tables (in-tree ✅)	✅
AC9	PCM16 @ 24kHz mono internal format; pluggable STT (default OpenAI gpt-4o-transcribe); SDK-side VAD fallback with one-shot warning	@ts-contract-surface / @ts-stt / @ts-vad units — CI-confirmed (same run)	✅
AC10	CI merge gate green — ci-checks (units + build + non-bot @ts-e2e) passes on HEAD	✅ ci-checks (24.x) pass (6m2s, suite executed) + javascript-complete/docs-complete/python-complete/evaluate all pass on HEAD 390e52c — run 26960103187. Fixed by rebase onto main + recording the @ungap/structured-clone override in pnpm-lock.yaml (f7273e7) + 2 stale doc-contract test assertions (f2cdf58). Local: 796 pass / 1 skip.	✅
AC11	Telephony transport (Twilio) — TwiML endpoint, signature rejection, tunnel harness, clear-buffer interrupt	@ts-twilio-proto + @ts-twilio-server integration scenarios bound — unit/integration layers CI-confirmed (same run)	✅
AC12	Remaining platform adapters (LiveKit, Vapi, generic WebRTC/WebSocket) raise PendingTransportError	stub adapters + units (✅ CI); full transports deferred to #371	✅

Net (honest read, updated 2026-06-04): all SDK-side ACs (AC1–12) are now ✅. AC1–6 were demo-recording-verified; AC7–9 + AC11 flipped from ⏳ to ✅ when the unit suite executed in CI for the first time on this PR — ci-checks (24.x) pass in 6m2s on HEAD 390e52c (run 26960103187), 796 pass / 1 skip. AC10's lockfile blocker is fixed (rebase onto main + @ungap/structured-clone override recorded in the lockfile + 2 stale doc-contract test assertions aligned).

App-side ACs — langwatch ingestion + rendering (SDK-green is necessary but NOT sufficient)

Parity is not done when the SDK suite passes — it's done when a voice scenario.run() is correctly ingested, queryable, and rendered in the langwatch app. These require a live end-to-end run (SDK → langwatch ingest → API/UI), not a unit test. Surface mapped against langwatch/langwatch:

#	App-side acceptance criterion	Concrete check	Status
AC13	Traces received — a voice run's OTel trace (incl. input_audio content parts) lands in langwatch	POST /api/collector ingests the span; trace appears for the project	✅ verified 2026-06-04 — live TS run scenariorun_3EfWWrSEiX95SWhzwUCwd7n22OA (openai_realtime_agent demo) landed 2 traces in project_bZspxwkhCD4POvqmIgOr2 with scenario.run_id metadata (sdk: langwatch-observability-sdk typescript 0.16.1); judge spans carry the audio as file parts: {"type":"file","mediaType":"audio/pcm16",…~230KB}
AC14	Traces queryable via API — the received trace is retrievable through the public API	POST /api/traces/search {projectId, filters} returns the voice run's trace	✅ POST /api/traces/search (startDate/endDate window) returned both: c50549165a184a73d5fb509525230755, 7c45a3b4edf40ad1466e33afd176b2f5; GET /api/trace/:id returns full span detail (5 spans incl. OpenAIRealtimeAgentAdapter.call, _JudgeAgent.call)
AC15	Scenario events ingested — RUN_STARTED / MESSAGE_SNAPSHOT / RUN_FINISHED persisted, each message carrying optional trace_id	scenario_events ES index holds the run's events; queryable via tRPC	✅ run persisted with 4 messages (MESSAGE_SNAPSHOT) carrying 8 input_audio content parts; the 2 assistant messages carry trace_id refs matching the two traces above (cross-linkage proven); status: SUCCESS + results.verdict: success (3/3 criteria) = RUN_FINISHED recorded
AC16	Scenario run visible in the app — the voice run shows in the simulations UI + REST	GET /api/simulation-runs/:scenarioRunId returns it; /[project]/simulations renders it	✅ GET /api/simulation-runs/scenariorun_3EfWWrSEiX95SWhzwUCwd7n22OA → HTTP 200 (demo_openai_realtime_agent, 41.8s, cost $0.0018); platformUrl: app.langwatch.ai/scenario-tracing-bZspxw/simulations (API-verified; in-app visual spot-check needs an authed browser — one click)
AC17	Audio messages rendered — input_audio content renders as an inline player, not a raw JSON blob	<ScenarioMessageRenderer> → <MediaPart> emits <audio controls> for the message	✅ shipped on langwatch@main via #4058 (the old #3781 is stale/superseded — not a blocker). MediaPart.tsx emits <audio data-testid="media-part-audio" controls> with onLoadedData probing; visit-content-part.ts handles input_audio parts; integration-tested (MediaPart.integration.test.tsx). The verified run's messages carry exactly the shape it renders: {"type":"input_audio","input_audio":{"mimeType":"audio/pcm16","url":"/api/files/so_…"}}
AC18	Audio itself verified — the rendered audio actually decodes + plays the correct content	base64 WAV decodes in <audio> (onLoadedData → ok); externalized blobs resolve via /api/files/:id	✅ verified byte-level 2026-06-04 on run scenariorun_3EfWWrSEiX95SWhzwUCwd7n22OA: GET /api/files/so_000000000002CR60L0eAWXH3ILtke → HTTP 200, 249,600 bytes; decodes as valid 5.20s pcm16 @ 24kHz mono (the AC9 contract format); OpenAI STT transcribes it to "Of course! Where would you like to go, or what kind of activities are you interested in?" — the coherent reply to the run's user turn "Hello, can you help me plan a weekend trip?". The user-side part (the SDK's other audio path — user-sim TTS) round-trips verbatim: 3.60s pcm16 → STT → "Hello, can you help me plan a weekend trip?", the exact scripted turn. Decode ✓ format ✓ correct-content ✓ both-paths ✓ serving-route ✓; the in-browser <audio> element rendering these same URLs is covered by the integration tests above. Follow-up hardening on-branch: 885d294 WAV-wraps raw pcm16 at the langwatch-bound converter (supersedes 5db36c8; e2e-verified in its commit: /api/files now serves audio/wav with a RIFF header, ffprobe-decodable) + 390e52c aligns the conversion test

Verification matrix (2026-06-04, all live against production app.langwatch.ai):

Every run below links to the live prod app — open it (project members) and press play on any audio message to hear the run the table describes.

Family / variant	Run	Ingest (AC13–15)	REST (AC16)	Audio bytes (AC18)
OpenAI Realtime (agent)	scenariorun_3EfWWrSEiX95SWhzwUCwd7n22OA	✅ 2 traces x-linked, 4 msgs / 8 parts	✅ 200, SUCCESS 3/3	✅ agent reply STT-coherent + user TTS verbatim round-trip
Gemini Live + interruption	scenariorun_3Efeze6fAvYmZd8gQeyVxz8SoOm	✅ 3 traces, 5 msgs / 5 parts — FAILED verdict persists correctly (2 met / 1 unmet). The unmet criterion is a judge semantic trap, not an adapter fault: the criterion says "over a real Gemini Live session" and the judge read the framework's own origin: simulation trace metadata as disqualifying — while its reasoning simultaneously confirms the live mid-utterance VAD cut-off. Vitest mechanics assertions: 3/3 pass. Suggested post-merge polish: drop the word "real" from that criterion	✅ 200	✅ truncated segment is its own cut-off transcript ("I am a large" / STT "I am a lar", 0.96s)
ElevenLabs hosted	scenariorun_3EffH3ID8Q7HU5S5anb2c8u4hhy	✅ 3 msgs / 3 parts	✅ 200, SUCCESS	✅ 1.56s → "Hello, how can I help you today?"
ElevenLabs branded + audioEffects	scenariorun_3EffKAJl4dXbP1IU41rxCzYyiwT	✅ 4 msgs / 4 parts	✅ 200, SUCCESS	✅ effects-processed audio STT-clean
Pipecat (mulaw@8000 source)	scenariorun_3EffZC024s9IrYTOaIoKbQawMpq	✅ 5 msgs / 5 parts, all normalized audio/pcm16 — AC9 contract held for a telephony source format	✅ 200, SUCCESS	✅ 3.80s → "Hello, thank you for calling. How can I help you today?"
Twilio (PSTN)	—	not runnable in this environment (needs live telephony + public tunnel); SDK layer CI-confirmed per AC11	—	—

App-side net (final, 2026-06-04): all app-side ACs (AC13–18) are ✅ verified against production across the adapter matrix — 5 live runs / 4 adapter families (matrix above), covering happy-path, interruption/truncation, failed-verdict persistence, audio effects, and a telephony source format. Every leg: SDK → collector → traces/search → simulation-runs REST → /api/files audio bytes, with message↔trace cross-linkage intact and served audio STT-verified as the correct conversational content at the contract format (pcm16/24kHz). The inline player shipped via #4058 (#3781 is stale, not a blocker). Parity board AC1–18: complete. Optional formality: eyeball any run at the simulations page — every layer beneath that click is independently verified.

What changed (decisions)

• Per-run provider state, not module-global (ADR-002): voice config rides on ScenarioConfig.voice and reaches the adapters per-run — no global configure(stt=). One AI-SDK file audio format end-to-end; STT/TTS are one-file-per-provider.
• agent({ wait: false }) is the barge-in primitive (PRD §4.4): the executor starts the agent's reply without blocking so a user() / interrupt() lands mid-utterance; the transport's native cancel fires and the cut-off segment is marked truncated.
• Demo promises are encoded as gates, split by what's verifiable: an LLM judge reading a transcript can't see audio properties, so judge criteria assert the conversational half (empathy, acknowledging the specific request, recovery) and deterministic code assertions assert the audio half (transcriptTruncated + shorter segment for cut-off; noise-floor ≫ silence for mixed ambience). A hollow demo now fails.
• Real-key voice demos run via a manual voice-integration workflow, not PR CI — mirroring Python's voice-integration.yml. They cost real API money and can flake, so they never gate a merge; ci-checks (units + build + the non-bot @ts-e2e gate) is the merge gate.
• Pre-step interrupt scheduling (maybeScheduleInterruptedAgentTurn, daa357d): ports Python's pre-step pattern; the executor decides to interrupt before the next agent turn begins rather than patching it up post-step. Eliminates the prior hollow post-step path.
• Inline-TTS barge-in (fa84c8f): voiceProceed fires the interrupt via voiceifyText while the AGENT is still in-flight, bypassing the user-sim LLM to win the race against fast-streaming bots. delayRange is honoured in this path (d20a49c).
• Pipecat adapter buffer-clear on interrupt (557cac2): sets a discardingInboundAudio flag so late bot frames don't contaminate the next agent turn.
• VoiceEvent discriminated union (4a49585): five variant interfaces (AgentSpeakingEvent, UserSpeakingEvent, etc.) replace the prior type:string — the compiler now narrows on event.type without casts.
• RealtimeUserAgent + VoiceUserSimulator structural interfaces + type guards (3f234f4): kills as unknown as casts in the executor; adapter conformance is checked structurally at compile time.
• interruptRng / interruptWaitForSpeechMs renamed to drop leading underscore (50cf3f2): test-seam fields are now @internal JSDoc-tagged rather than visually private — consistent with the project's naming convention.
• interruption_recovery judge promoted to hard gate (5bce766): was informative-only; now the scenario fails if the judge says the agent didn't recover. Recording regenerated at be600de.
• Gemini Live spurious-pair handling proven by 3 new adapter unit tests (4bd40c6): receiveAudio() deduplicate logic is exercised deterministically without a live connection.
• Docs caught up to the shipped API (4 commits, 8eb7f55…c9c0f9a):
  • recipes/interrupt.mdx now documents voiceProceed({ interruptions: new InterruptionConfig({...}) }) — the PR's primary random-barge-in API — alongside the explicit agent({ wait: false }) + interrupt() primitive
  • adapters/pipecat.mdx capability table corrected (drops opus that the TS adapter doesn't support; source: pipecat.ts:139-140)
  • adapters/elevenlabs.mdx adds systemPromptOverride / firstMessageOverride per-session options
  • recipes/effects.mdx drops the stale "on the roadmap" callout (Python script.py:user() already accepts voice_style + audio_effects)

How it works

Module tree — 45 created + 18 modified source modules (+44 test files) under javascript/src/, single responsibilities, and how it functions together

Created

javascript/src/
├── config/configure.ts ················ global scenario configuration entry point (voice config rides ScenarioConfig.voice per ADR-002 — no module-global)
├── domain/agents/agent-shapes.ts ······ narrow structural interfaces for duck-typed user-simulator capabilities
├── script/voice-steps.ts ·············· voice script steps (sleep/silence/audio/dtmf/interrupt) + voiceProceed pre-step scheduling
└── voice/
    ├── config.ts ······················ per-run VoiceConfig + resolveVoiceConfig — keystone of the voice state model
    ├── adapter.runtime.ts ············· executor-side adapter wiring: connected-state gate, defaultVoiceCall, response draining
    ├── messages.ts ···················· the SOLE AudioChunk ↔ ModelMessage gateway (unified audio-message producer)
    ├── factories.ts ··················· lowercase adapter factories (PRD §9 idiom): openAIRealtimeAgent(), pipecatAgent(), …
    ├── interruption.ts ················ InterruptionConfig for proceed({ interruptions }) — probabilistic barge-in
    ├── vad.ts ························· SDK-side VAD fallback for adapters without native VAD (one-shot warning)
    ├── judge-stt.ts ··················· judge STT pre-pass — auto-transcription seam for non-multimodal judges
    ├── transcribe.ts ·················· post-hoc STT over a VoiceRecording (fills segment transcripts)
    ├── recording.runtime.ts ··········· WAV/MP3 save + segment directory + byte-accurate JSON manifest
    ├── playback.ts ···················· local-speaker playback sink (configure({ audioPlayback }))
    ├── segment-utils.ts ··············· pure segment/timeline post-processing (byte-cursor model)
    ├── ffmpeg.ts ······················ ffmpeg binary resolution (bundled via ffmpeg-static — no system dep)
    ├── utils.ts ······················· shared voice-layer utilities
    ├── agent-shapes.ts ················ @deprecated re-export shim → domain/agents/agent-shapes
    ├── adapters/ ······················ one transport per file
    │   ├── openai-realtime.ts ········· OpenAI Realtime (agent + user roles — the model IS the agent)
    │   ├── gemini-live.ts ············· Gemini Live native-audio (real server-VAD barge-in)
    │   ├── elevenlabs.ts ·············· ElevenLabs hosted ConvAI + branded transports
    │   ├── pipecat.ts ················· WebSocket client to a user-run Pipecat bot (pcm16/mulaw/opus)
    │   ├── twilio.ts ·················· real-phone transport via Twilio Media Streams
    │   ├── twilio-server.ts ··········· TwiML webhook + WS server impersonating Twilio's edge locally
    │   ├── twilio-shared.ts ··········· shared Media-Streams primitives (one canonical copy — Gap #6)
    │   ├── twilio-tunnel.ts ··········· public-tunnel harness so Twilio can reach the local server
    │   ├── twilio-logger.ts ··········· minimal parity logger for the Twilio adapter
    │   ├── composable.ts ·············· ComposableVoiceAgent: local STT → LLM → TTS (voice-test a text agent without a transport)
    │   ├── pending-transport-error.ts · PendingTransportError for stub transports (LiveKit/Vapi/WebRTC/WS — full transports → #371)
    │   └── index.ts ··················· adapter barrel
    ├── stt/ ··························· pluggable speech-to-text
    │   ├── stt-provider.ts ············ provider contract + "provider/model" router
    │   ├── openai-stt.ts ·············· default leaf (gpt-4o-transcribe)
    │   ├── elevenlabs-stt.ts ·········· ElevenLabs Scribe leaf
    │   ├── wav.ts ····················· minimal RIFF/WAV encoder for the STT upload edge
    │   └── index.ts ··················· barrel + registration site
    ├── tts/ ··························· pluggable text-to-speech
    │   ├── tts.ts ····················· router + cache core
    │   ├── openai-tts.ts ·············· default openai/<voice> leaf
    │   ├── elevenlabs-tts.ts ·········· elevenlabs/<voiceId> leaf (Gap #10)
    │   └── index.ts ··················· barrel + registration site
    ├── effects/ ······················· user-simulator audio-effects pipeline (§4.5)
    │   ├── index.ts ··················· pipeline + public surface
    │   ├── common.ts ·················· PCM16 @ 24kHz mono bytes ↔ Int16Array helpers
    │   ├── noise.ts ··················· backgroundNoise, static, multipleVoices
    │   ├── quality.ts ················· phoneQuality, lowQuality, packetLoss, echo, robotic, breakingUp
    │   ├── prosody.ts ················· volume scaling, time-stretching
    │   └── custom.ts ·················· arbitrary user Uint8Array → Uint8Array effects
    └── assets/noise/ ·················· 5 bundled noise WAVs (airport/babble/cafe/office/street) + LICENSES.md

Modified (existing modules the voice layer hooks into)

javascript/src/
├── index.ts ··························· public surface: voice namespace + lowercase factories exported
├── runner/run.ts ······················ scenario.run() host — resolves per-run voice config, threads it to the executor
├── execution/scenario-execution.ts ···· executor core — voice turn loop, pre-step interrupted-agent scheduling, interruptOverrides test seam
├── execution/scenario-execution-state.ts  run state — carries the voice executor reference across resets
├── agents/user-simulator-agent.ts ····· voice-aware user sim — per-run TTS voice, persona, audioEffects
├── agents/judge/judge-agent.ts ········ voice-aware judge — audio auto-detect, transcript fallback, structured timeline
├── config/index.ts ···················· config barrel — ScenarioConfig.voice wiring
├── domain/agents/index.ts ············· domain barrel — UserSimulatorAgentWithVoice
├── domain/core/execution.ts ··········· core types — agent({ wait:false }) non-blocking primitive
├── domain/scenarios/index.ts ·········· scenario domain types — voice fields
├── script/index.ts ···················· script barrel — voice steps surfaced
├── utils/convert-core-messages-to-agui-messages.ts  message conversion — audio file parts → input_audio; raw pcm16 is RIFF/WAV-wrapped at this langwatch-bound boundary so the app player decodes it (`885d294`)
└── voice/ (pre-existing PR1 bases, extended)
    ├── adapter.ts ····················· VoiceAgentAdapter base + AdapterCapabilities contract (+ isConnected gate)
    ├── index.ts ······················· voice namespace barrel
    ├── messages.types.ts ·············· audio message type surface
    ├── recording.types.ts ············· VoiceRecording/segment type surface
    ├── voice-executor-state.ts ········ runtime voice state — agent-speaking event, byte cursor
    └── voice-models.ts ················ canonical model ids (OPENAI_REALTIME_MODEL, …)

How it functions together

scenario.run({ voice }) (runner/run.ts) resolves a per-run VoiceConfig (voice/config.ts — no module-global state, ADR-002) and hands it to the executor (execution/scenario-execution.ts), which connects the chosen transport (voice/adapters/*) through the uniform connected-state gate (voice/adapter.runtime.ts). On each user turn the simulator (agents/user-simulator-agent.ts) synthesizes speech via the TTS router (voice/tts/) and layers realism through the effects pipeline (voice/effects/ + bundled assets/noise/); audio streams over the transport and the agent's reply is drained on tail-silence windows (adapter.runtime.ts). Every chunk crosses a single gateway (voice/messages.ts) into ModelMessages carrying input_audio file parts — the exact shape langwatch ingests (utils/convert-core-messages-to-agui-messages.ts). Barge-ins come from script steps (script/voice-steps.ts) or probabilistic config (voice/interruption.ts): native server-VAD where the adapter supports it, SDK fallback otherwise (voice/vad.ts), with truncation marked on the byte cursor (voice/segment-utils.ts, voice-executor-state.ts). At judgment time a pre-pass (voice/judge-stt.ts → voice/stt/) transcribes audio for non-multimodal judges (agents/judge/judge-agent.ts). The run's audio persists as full.wav + per-segment files + a byte-accurate manifest (voice/recording.runtime.ts), optionally monitored live (voice/playback.ts), and rides ScenarioResult alongside timeline + latency extensions.

Asset parity: the 5 noise WAVs are byte-identical between javascript/src/voice/assets/noise/ and python/scenario/voice/assets/noise/ (md5-verified 2026-06-04, 144,044 B each), produced by the single deterministic generator javascript/scripts/generate-noise-samples.mjs; both sides carry LICENSES.md.

File-org corrections (from audit)

Three PR-internal file-org corrections landed late in the PR after a structure audit:

• scripts/generate-noise-samples.mjs → javascript/scripts/ (TS-only generator belongs in package scripts, not repo-root cross-language scripts)
• docs/voice/internal-design.md → docs/adr/003-voice-internal-design.md (it's an ADR by description; lives with ADR-001/002)
• javascript/examples/vitest/recordings/ → javascript/examples/vitest/outputs/recordings/ (semantic clarity + future-proof for traces/logs siblings)

Pre-existing-on-main cleanup landed separately as PR #586 (deletes orphan docs, publishes happy-path guides, folds capability-matrix duplication, python recordings → outputs/recordings rename, python noise-sample parity refresh). After #586 merges this branch rebases off cleaned main.

Test plan

• pnpm -F @langwatch/scenario test → 791 pass / 1 skipped (incl. the new interrupt-truncation, noise-energy, byte-cursor, proceed-loop pre-step, and Gemini Live spurious-pair unit tests).
• @ts-e2e round-trip gate (real keys) green; tsc --noEmit, build:all, lint:all, typecheck:all clean.
• Regression guard: the interrupt clock-mismatch fix is covered by a unit test exercising divergent cursor-vs-wall-clock times (the prior same-scale test masked the bug).

How I can prove it works

16 committed demo recordings (javascript/examples/vitest/outputs/recordings/<demo>/ — full.wav + byte-accurate manifest.json), generated against live providers + the bundled Pipecat bot. The ones demonstrating the headline behaviors (open the blob → GitHub shows an audio player):

Behavior	Demo
Reply cut off mid-sentence, then recovers (judge hard-gated)	interruption_recovery
Probabilistic barge-ins via inline-TTS + canned-phrase strategy	random_interruptions
Server-VAD barge-in on Gemini Live (real mid-stream cut-off)	gemini_live_interruption
Audible anger (ElevenLabs tonal markers) + cafe noise	angry_customer
Genuine engagement, not a canned greeting	basic_greeting

Full set (16) also covers the adapters (openai_realtime ×2, elevenlabs hosted/branded, gemini_live), composable_stt_swap, recording_playback, voice_text_parity, pipecat ×2, background_handoff.

Anything surprising

• evaluate check is red — expected & non-blocking, fix lands with PR chore: main-side cleanup — docs + spec + python/TS parity #586. This PR's diff exceeds GitHub's 20k-line API cap, so the eval bot can't fetch it (HTTP 406). Not a required check. PR #586 (commits bafdbf7e15 + cdce271bb2) catches the 406 with a grep-specific oversized=true path + env: pattern hardening for oversized_reason; supersedes PR fix(ci/#571): soft-pass oversized PR diffs in pr-auto-approve evaluate #572 and closes ci: evaluate workflow hard-fails on PRs >20k-line diff instead of its oversized path #571 on merge. Once chore: main-side cleanup — docs + spec + python/TS parity #586 merges and this branch rebases on the new main, evaluate will go green on this PR too.
• The 6 Pipecat-bot demos run only in the manual voice-integration workflow (which now sets SCENARIO_PIPECAT_BOT_UP); pre-merge they're proven by the committed recordings + local real-key runs, and the workflow guards them post-merge.
• random_interruptions recording is honest about Pipecat-bot limits. The bundled Pipecat stub bot bursts TTS frames in ~50 ms of wall time (not realtime streaming), so by the time adapter.interrupt() fires the bot has already sent all frames — real mid-stream audio cut-off isn't observable with this transport. The demo's assertions encode what the bot can prove: interrupt fires + fired_after_speech outcome + canned-phrase strategy ran + truncation label + agent recovers + multi-turn conversation. For real audio cut-off under server-side cancel, see gemini_live_interruption. A transport-upgrade follow-up is drafted (see /tmp/voice-spec/issue-random-interruptions-followup.md).
• Follow-ups filed: fix(voice/python): port noise-sample generator + split audio-property claims out of judge criteria (TS parity from #561) #568 (Python demo-fidelity parity), fix(voice/ts): AgentSpeakingEvent.set() fires on an empty first audio chunk (adapter.runtime.ts) #569 (speakingEvent empty-chunk), harden(voice/ts): validate paths/URLs in backgroundNoise/multipleVoices + pipecat adapter #570 (path/URL hardening), ci: evaluate workflow hard-fails on PRs >20k-line diff instead of its oversized path #571 (evaluate oversized-diff). Remaining transports (LiveKit/Vapi/WebRTC/WebSocket) tracked under Voice agents: remaining platform adapter transports #371.

🤖 Generated with Claude Code

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Closes (574-585 grind — landed in this PR)

Closes #574 #575 #576 #578 #579 #580 #581 #582 #583 #584 #585

All 11 follow-up issues from the post-review NIT batch were addressed in this PR via 60+ commits since 4d83724. Per-issue close-out comments are on each issue; partial outcomes for #580 (Gemini adapter improved, demo workaround retained) and #583 (adapter dequeue race fixed, transport switch reverted) are documented honestly there.

[drewdrewthis]

🎧 Voice demo recordings — click to listen

Real audio captured from each demo's scenario.run() (committed under javascript/recordings/<demo>/). Click to play in a browser tab:

Demo	Listen
OpenAI Realtime — agent	▶ play
OpenAI Realtime — user-sim	▶ play
ElevenLabs — hosted ConvAI	▶ play
ElevenLabs — branded/composable	▶ play
Gemini Live	▶ play
Composable (STT swap)	▶ play
Pipecat (WebSocket)	▶ play
Recording + playback	▶ play
Voice ↔ text parity	▶ play

Embedded player: GitHub renders a player only for files uploaded as comment attachments — drag a .wav into a reply box and it embeds inline. Per-segment WAVs + manifest.json live in each demo folder.

[drewdrewthis]

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[github-actions]

Automated low-risk assessment

This PR was evaluated against the repository's Low-Risk Pull Requests procedure and does not qualify as low risk.

This PR's diff could not be evaluated automatically: Diff too large to fetch via GitHub API (fetch error: could not find pull request diff: HTTP 406: Sorry, the diff exceeded the maximum number of lines (20000) (https://api.github.com/repos/langwatch/scenario/pulls/561)
PullRequest.diff too_large). Manual review required.

This PR requires a manual review before merging.