backend/lm-livekit-helper.git

			@@ -1,8 +1,12 @@
			mod asr_realtime;
			mod audio;
			mod service;

			use std::{
			borrow::Cow,
			collections::HashSet,
			env, fs,
			future::Future,
			path::{Path, PathBuf},
			sync::{
			Arc,
			@@ -12,6 +16,9 @@
			};

			use anyhow::{Context, Result, anyhow};
			use asr_realtime::{
			AudioIngressMetadata, RealtimeAsrConfig, RealtimeAsrOutcome, RealtimeAsrUpload,
			};
			use audio::{AudioDiagnostics, load_pre_recorded_frames};
			use base64::{Engine as _, engine::general_purpose};
			use futures_util::StreamExt;
			@@ -24,23 +31,541 @@
			options::TrackPublishOptions,
			prelude::{
			DataPacket, LocalAudioTrack, LocalTrack, ParticipantIdentity, RemoteAudioTrack,
			RemoteTrack, Room, RoomEvent, RoomOptions,
			RemoteParticipant, RemoteTrack, Room, RoomEvent, RoomOptions,
			},
			};
			use reqwest::Client;
			use serde::{Deserialize, Serialize};
			use serde_json::json;
			use tokio::time::{sleep, sleep_until};
			use tokio::{sync::mpsc::UnboundedReceiver, task::JoinHandle};
			use sha2::{Digest, Sha256};
			use tokio::time::{sleep, sleep_until, timeout};
			use tokio::{
			sync::{mpsc, mpsc::UnboundedReceiver, watch},
			task::JoinHandle,
			};
			use tracing::{info, warn};

			const USER_AUDIO_SAMPLE_RATE_HZ: u32 = 48_000;
			const USER_AUDIO_NUM_CHANNELS: u16 = 1;
			const INBOUND_AUDIO_QUEUE_CAPACITY: usize = 100;
			const INBOUND_AUDIO_DROP_LOG_INTERVAL: u64 = 100;
			const AUDIO_DRAIN_STOP_GRACE: Duration = Duration::from_secs(2);
			const DEFAULT_BOT_AUDIO_PROFILE: &str = "pcm-16k";
			const LIVEKIT_48K_SAMPLE_RATE_HZ: u32 = 48_000;
			const PCM_16K_SAMPLE_RATE_HZ: u32 = 16_000;
			const BOT_NUM_CHANNELS: u16 = 1;
			const TRACK_NAME: &str = "bot-main-audio";
			const STREAM_TIMING_VERSION: u32 = 1;
			const STREAM_TIMING_FIRST_SEGMENT: u64 = 1;
			const STREAM_TIMING_FIRST_CHUNK: u64 = 1;
			const STREAM_TIMING_MAX_ELAPSED_MS: u64 = 5_000;
			const STREAM_TIMING_SOURCE: &str = "stream_anchor_monotonic";
			const CONTROLLED_FIXTURE_PROBE_TOPIC: &str = "controlled_fixture_attribute_probe";
			const CONTROLLED_FIXTURE_ACK_TOPIC: &str = "controlled_fixture_attribute_ack";
			const CONTROLLED_FIXTURE_PROTOCOL_VERSION: u64 = 1;
			const CONTROLLED_FIXTURE_GENERATION: u64 = 1;
			const CONTROLLED_FIXTURE_PROBE_RECHECK_DELAY: Duration = Duration::from_millis(25);
			const CONTROLLED_FIXTURE_PROBE_TTL: Duration = Duration::from_millis(250);
			const CONTROLLED_FIXTURE_POST_EXPIRY_WINDOW: Duration = Duration::from_millis(2_000);

			const CONTROLLED_FIXTURE_ACK_RESULTS: [&str; 4] =
			["observed", "rejected", "timeout", "publish_failed"];
			const CONTROLLED_FIXTURE_REJECT_REASONS: [&str; 10] = [
			"missing_attributes",
			"wrong_source",
			"missing_sequence",
			"wrong_sequence",
			"wrong_participant",
			"expired",
			"duplicate_or_old_sequence",
			"no_current_participant",
			"ack_publish_failed",
			"unknown",
			];

			#[derive(Debug, Deserialize)]
			#[serde(rename_all = "camelCase")]
			struct ControlledFixtureAttributeProbe {
			#[serde(rename = "type")]
			message_type: String,
			protocol_version: u64,
			call_id_hash: String,
			call_trace_id_hash: String,
			generation: u64,
			client_fixture_sequence: String,
			}

			#[derive(Debug, Serialize)]
			#[serde(rename_all = "camelCase")]
			struct ControlledFixtureAttributeAck {
			#[serde(rename = "type")]
			message_type: &'static str,
			protocol_version: u64,
			call_id_hash: String,
			call_trace_id_hash: String,
			generation: u64,
			client_fixture_sequence: String,
			result: &'static str,
			#[serde(skip_serializing_if = "Option::is_none")]
			input_source_category: Option<&'static str>,
			#[serde(skip_serializing_if = "Option::is_none")]
			reject_reason: Option<&'static str>,
			}

			#[derive(Clone, Debug)]
			struct PendingControlledFixtureProbe {
			sender: ParticipantIdentity,
			call_id_hash: String,
			call_trace_id_hash: String,
			generation: u64,
			sequence: String,
			received_at: Instant,
			expires_at: Instant,
			}

			#[derive(Debug, PartialEq, Eq)]
			struct ControlledFixtureVisibilityEvidence {
			first_visible_bucket: &'static str,
			visibility_source: &'static str,
			binding_matched: bool,
			}

			#[derive(Debug, PartialEq, Eq)]
			struct ControlledFixtureAckPublishOutcome {
			observed: bool,
			published: bool,
			}

			fn sha256_hex(value: &str) -> String {
			let mut digest = Sha256::new();
			digest.update(value.as_bytes());
			digest
			.finalize()
			.iter()
			.map(\|byte\| format!("{byte:02x}"))
			.collect()
			}

			fn controlled_fixture_ack_classification(
			decision: Result<(), &'static str>,
			) -> (&'static str, Option<&'static str>, bool) {
			match decision {
			Ok(()) => ("observed", None, true),
			Err("timeout") => ("timeout", Some("expired"), false),
			Err(reason) if CONTROLLED_FIXTURE_REJECT_REASONS.contains(&reason) => {
			("rejected", Some(reason), false)
			}
			Err(_) => ("rejected", Some("unknown"), false),
			}
			}

			fn record_controlled_fixture_probe_event(
			runtime_call_id: &str,
			runtime_trace_id: &str,
			stage: &'static str,
			call_id_hash: &str,
			trace_id_hash: &str,
			generation: u64,
			sequence: &str,
			observed: bool,
			ack_result: Option<&'static str>,
			reject_reason: Option<&'static str>,
			) {
			debug_assert!(ack_result.is_none_or(\|value\| CONTROLLED_FIXTURE_ACK_RESULTS.contains(&value)));
			debug_assert!(
			reject_reason.is_none_or(\|value\| CONTROLLED_FIXTURE_REJECT_REASONS.contains(&value))
			);
			println!(
			"{}",
			controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			stage,
			call_id_hash,
			trace_id_hash,
			generation,
			sequence,
			observed,
			ack_result,
			reject_reason,
			)
			);
			}

			fn controlled_fixture_probe_event(
			runtime_call_id: &str,
			runtime_trace_id: &str,
			stage: &'static str,
			call_id_hash: &str,
			trace_id_hash: &str,
			generation: u64,
			sequence: &str,
			observed: bool,
			ack_result: Option<&'static str>,
			reject_reason: Option<&'static str>,
			) -> serde_json::Value {
			json!({
			"type": "cv_activity",
			"callId": runtime_call_id,
			"traceId": runtime_trace_id,
			"turnId": null,
			"eventName": "controlled_fixture_attribute_probe",
			"eventWallTimeMs": current_time_millis(),
			"result": "ok",
			"reasonCode": null,
			"retryable": null,
			"extension": {
			"stage": stage,
			"observed": observed,
			"ack_result": ack_result,
			"reject_reason": reject_reason,
			"call_id_hash": call_id_hash,
			"trace_id_hash": trace_id_hash,
			"generation": generation,
			"sequence_hash": sha256_hex(sequence),
			},
			})
			}

			fn record_controlled_fixture_attribute_decision(
			decision: Result<(), &'static str>,
			runtime_call_id: &str,
			runtime_trace_id: &str,
			call_id_hash: &str,
			trace_id_hash: &str,
			generation: u64,
			sequence: &str,
			) -> (&'static str, Option<&'static str>, bool) {
			let classification = controlled_fixture_ack_classification(decision);
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"attributes_classified",
			call_id_hash,
			trace_id_hash,
			generation,
			sequence,
			classification.2,
			Some(classification.0),
			classification.1,
			);
			classification
			}

			async fn complete_controlled_fixture_ack_publish<F, E>(
			publish: F,
			runtime_call_id: &str,
			runtime_trace_id: &str,
			observed: bool,
			ack_result: &'static str,
			reject_reason: Option<&'static str>,
			call_id_hash: &str,
			trace_id_hash: &str,
			generation: u64,
			sequence: &str,
			acknowledged_probe_sequences: &mut HashSet<String>,
			) -> ControlledFixtureAckPublishOutcome
			where
			F: Future<Output = Result<(), E>>,
			{
			if publish.await.is_ok() {
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"ack_publish_completed",
			call_id_hash,
			trace_id_hash,
			generation,
			sequence,
			observed,
			Some(ack_result),
			reject_reason,
			);
			acknowledged_probe_sequences.insert(sequence.to_string());
			ControlledFixtureAckPublishOutcome {
			observed,
			published: true,
			}
			} else {
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"ack_publish_completed",
			call_id_hash,
			trace_id_hash,
			generation,
			sequence,
			false,
			Some("publish_failed"),
			Some("ack_publish_failed"),
			);
			ControlledFixtureAckPublishOutcome {
			observed: false,
			published: false,
			}
			}
			}

			fn controlled_fixture_ack_from_probe(
			probe: &PendingControlledFixtureProbe,
			observed: bool,
			reject_reason: Option<&'static str>,
			) -> ControlledFixtureAttributeAck {
			ControlledFixtureAttributeAck {
			message_type: CONTROLLED_FIXTURE_ACK_TOPIC,
			protocol_version: CONTROLLED_FIXTURE_PROTOCOL_VERSION,
			call_id_hash: probe.call_id_hash.clone(),
			call_trace_id_hash: probe.call_trace_id_hash.clone(),
			generation: probe.generation,
			client_fixture_sequence: probe.sequence.clone(),
			result: if observed { "observed" } else { "rejected" },
			input_source_category: observed.then_some("controlled_fixture"),
			reject_reason,
			}
			}

			fn controlled_fixture_probe(
			payload: &[u8],
			call_id: &str,
			trace_id: &str,
			sender: &ParticipantIdentity,
			expected_participant: Option<&str>,
			) -> Option<PendingControlledFixtureProbe> {
			if !is_bound_user_participant(sender.as_str(), expected_participant) {
			return None;
			}
			let probe: ControlledFixtureAttributeProbe = serde_json::from_slice(payload).ok()?;
			if probe.message_type != CONTROLLED_FIXTURE_PROBE_TOPIC
			\|\| probe.protocol_version != CONTROLLED_FIXTURE_PROTOCOL_VERSION
			\|\| probe.generation != CONTROLLED_FIXTURE_GENERATION
			\|\| probe.call_id_hash != sha256_hex(call_id)
			\|\| probe.call_trace_id_hash != sha256_hex(trace_id)
			\|\| probe.client_fixture_sequence.trim().is_empty()
			{
			return None;
			}
			let received_at = Instant::now();
			Some(PendingControlledFixtureProbe {
			sender: sender.clone(),
			call_id_hash: probe.call_id_hash,
			call_trace_id_hash: probe.call_trace_id_hash,
			generation: probe.generation,
			sequence: probe.client_fixture_sequence,
			received_at,
			expires_at: received_at + CONTROLLED_FIXTURE_PROBE_TTL,
			})
			}

			fn controlled_fixture_visibility_bucket(elapsed: Duration) -> &'static str {
			if elapsed <= Duration::from_millis(250) {
			"lte_250ms"
			} else if elapsed <= Duration::from_millis(500) {
			"250_500ms"
			} else if elapsed <= Duration::from_millis(1_000) {
			"500_1000ms"
			} else {
			"1000_2000ms"
			}
			}

			async fn observe_controlled_fixture_post_expiry<F>(
			received_at: Instant,
			observation_deadline: Instant,
			actual_participant: &str,
			expected_participant: Option<&str>,
			requested_sequence: &str,
			lifecycle_active: Arc<AtomicBool>,
			mut read_attributes: F,
			) -> Option<ControlledFixtureVisibilityEvidence>
			where
			F: FnMut() -> std::collections::HashMap<String, String>,
			{
			loop {
			if !lifecycle_active.load(Ordering::Acquire) {
			return None;
			}
			let now = Instant::now();
			let decision = classify_controlled_fixture_attributes(
			actual_participant,
			expected_participant,
			&read_attributes(),
			requested_sequence,
			);
			match decision {
			Ok(()) => {
			return Some(ControlledFixtureVisibilityEvidence {
			first_visible_bucket: controlled_fixture_visibility_bucket(
			now.saturating_duration_since(received_at),
			),
			visibility_source: "participant_attributes_poll",
			binding_matched: true,
			});
			}
			Err("missing_attributes") if now < observation_deadline => {}
			Err("missing_attributes") => {
			return Some(ControlledFixtureVisibilityEvidence {
			first_visible_bucket: "never_visible_within_observation_window",
			visibility_source: "participant_attributes_poll",
			binding_matched: true,
			});
			}
			Err(_) => return None,
			}
			sleep(CONTROLLED_FIXTURE_PROBE_RECHECK_DELAY).await;
			}
			}

			fn controlled_fixture_visibility_event(
			runtime_call_id: &str,
			runtime_trace_id: &str,
			probe: &PendingControlledFixtureProbe,
			evidence: &ControlledFixtureVisibilityEvidence,
			) -> serde_json::Value {
			json!({
			"type": "cv_activity",
			"callId": runtime_call_id,
			"traceId": runtime_trace_id,
			"turnId": null,
			"eventName": "controlled_fixture_attribute_probe",
			"eventWallTimeMs": current_time_millis(),
			"result": "ok",
			"reasonCode": null,
			"retryable": null,
			"extension": {
			"stage": "post_expiry_visibility",
			"first_visible_bucket": evidence.first_visible_bucket,
			"visibility_source": evidence.visibility_source,
			"binding_matched": evidence.binding_matched,
			"call_id_hash": probe.call_id_hash,
			"trace_id_hash": probe.call_trace_id_hash,
			"generation": probe.generation,
			"sequence_hash": sha256_hex(&probe.sequence),
			"evidence_count": 1,
			},
			})
			}

			fn spawn_controlled_fixture_post_expiry_observation(
			probe: PendingControlledFixtureProbe,
			participant: RemoteParticipant,
			expected_participant: Option<String>,
			lifecycle_active: Arc<AtomicBool>,
			runtime_call_id: String,
			runtime_trace_id: String,
			) {
			tokio::spawn(async move {
			let participant_identity = participant.identity().to_string();
			let evidence = observe_controlled_fixture_post_expiry(
			probe.received_at,
			probe.received_at + CONTROLLED_FIXTURE_POST_EXPIRY_WINDOW,
			&participant_identity,
			expected_participant.as_deref(),
			&probe.sequence,
			lifecycle_active.clone(),
			\|\| participant.attributes(),
			)
			.await;
			if lifecycle_active.load(Ordering::Acquire) {
			if let Some(evidence) = evidence {
			println!(
			"{}",
			controlled_fixture_visibility_event(
			&runtime_call_id,
			&runtime_trace_id,
			&probe,
			&evidence,
			)
			);
			}
			}
			});
			}

			fn classify_controlled_fixture_attributes(
			actual_participant: &str,
			expected_participant: Option<&str>,
			attributes: &std::collections::HashMap<String, String>,
			requested_sequence: &str,
			) -> Result<(), &'static str> {
			if !is_bound_user_participant(actual_participant, expected_participant) {
			return Err("wrong_participant");
			}
			let source = attributes
			.get("inputSourceCategory")
			.map(String::as_str)
			.unwrap_or("");
			if source != "controlled_fixture" {
			return Err(if source.is_empty() {
			"missing_attributes"
			} else {
			"wrong_source"
			});
			}
			let sequence = attributes
			.get("clientFixtureSequence")
			.map(String::as_str)
			.unwrap_or("");
			if sequence.trim().is_empty() {
			return Err("missing_sequence");
			}
			if sequence != requested_sequence {
			return Err("wrong_sequence");
			}
			Ok(())
			}

			async fn observe_controlled_fixture_attributes<F>(
			expires_at: Instant,
			actual_participant: &str,
			expected_participant: Option<&str>,
			requested_sequence: &str,
			mut read_attributes: F,
			) -> Result<(), &'static str>
			where
			F: FnMut() -> std::collections::HashMap<String, String>,
			{
			loop {
			if Instant::now() > expires_at {
			return Err("timeout");
			}
			let decision = classify_controlled_fixture_attributes(
			actual_participant,
			expected_participant,
			&read_attributes(),
			requested_sequence,
			);
			if decision.is_ok() \|\| !matches!(decision, Err("missing_attributes")) {
			return decision;
			}
			let Some(next_check) = Instant::now().checked_add(CONTROLLED_FIXTURE_PROBE_RECHECK_DELAY)
			else {
			return Err("timeout");
			};
			if next_check > expires_at {
			return Err("timeout");
			}
			sleep(CONTROLLED_FIXTURE_PROBE_RECHECK_DELAY).await;
			}
			}

			fn controlled_fixture_observer_gate(pending_probe: bool, probe_result: Option<bool>) -> bool {
			!pending_probe \|\| probe_result == Some(true)
			}

			fn start_observer_after_controlled_fixture_probe<F>(
			pending_probe: bool,
			probe_result: Option<bool>,
			spawn: F,
			) -> bool
			where
			F: FnOnce(),
			{
			if !controlled_fixture_observer_gate(pending_probe, probe_result) {
			return false;
			}
			spawn();
			true
			}

			#[tokio::main(flavor = "multi_thread")]
			async fn main() -> Result<()> {
			@@ -270,6 +795,11 @@
			runtime_turn_bridge_url: Option<String>,
			runtime_turn_bridge_token: Option<String>,
			runtime_turn_bridge_mode: String,
			runtime_asr_stream_enabled: bool,
			runtime_asr_stream_url: Option<String>,
			runtime_asr_realtime_enabled: bool,
			runtime_asr_realtime_url: Option<String>,
			runtime_asr_realtime_chunk_duration_ms: u64,
			runtime_turn_artifact_dir: Option<String>,
			runtime_session_nonce: Option<String>,
			user_audio_observer_enabled: bool,
			@@ -332,6 +862,11 @@
			bridge_url: Option<String>,
			bridge_token: Option<String>,
			bridge_mode: String,
			asr_stream_enabled: bool,
			asr_stream_url: Option<String>,
			asr_realtime_enabled: bool,
			asr_realtime_url: Option<String>,
			asr_realtime_chunk_duration_ms: u64,
			artifact_dir: Option<String>,
			runtime_session_nonce: Option<String>,
			audio_debug_dump_dir: Option<String>,
			@@ -343,6 +878,11 @@
			bridge_url: config.runtime_turn_bridge_url.clone(),
			bridge_token: config.runtime_turn_bridge_token.clone(),
			bridge_mode: config.runtime_turn_bridge_mode.clone(),
			asr_stream_enabled: config.runtime_asr_stream_enabled,
			asr_stream_url: config.runtime_asr_stream_url.clone(),
			asr_realtime_enabled: config.runtime_asr_realtime_enabled,
			asr_realtime_url: config.runtime_asr_realtime_url.clone(),
			asr_realtime_chunk_duration_ms: config.runtime_asr_realtime_chunk_duration_ms,
			artifact_dir: config.runtime_turn_artifact_dir.clone(),
			runtime_session_nonce: config.runtime_session_nonce.clone(),
			audio_debug_dump_dir: config.audio_debug_dump_dir.clone(),
			@@ -374,6 +914,32 @@
			.as_deref()
			.is_some_and(\|value\| value.trim_end_matches('/').ends_with("/stream"))
			}

			fn is_asr_stream_ready(&self) -> bool {
			self.asr_stream_enabled
			&& self
			.asr_stream_url
			.as_ref()
			.is_some_and(\|value\| !value.is_empty())
			&& self
			.bridge_token
			.as_ref()
			.is_some_and(\|value\| !value.is_empty())
			&& self
			.runtime_session_nonce
			.as_ref()
			.is_some_and(\|value\| !value.is_empty())
			}

			fn realtime_asr_config(&self) -> RealtimeAsrConfig {
			RealtimeAsrConfig {
			enabled: self.asr_realtime_enabled,
			url: self.asr_realtime_url.clone(),
			runtime_token: self.bridge_token.clone(),
			runtime_session_nonce: self.runtime_session_nonce.clone(),
			chunk_duration_ms: self.asr_realtime_chunk_duration_ms,
			}
			}
			}

			impl Config {
			@@ -395,6 +961,14 @@
			runtime_turn_bridge_token: optional_env("CV_RUNTIME_TURN_BRIDGE_TOKEN"),
			runtime_turn_bridge_mode: env::var("CV_RUNTIME_TURN_BRIDGE_MODE")
			.unwrap_or_else(\|_\| "json".to_string()),
			runtime_asr_stream_enabled: bool_env("CV_RUNTIME_ASR_STREAM_ENABLED", false),
			runtime_asr_stream_url: optional_env("CV_RUNTIME_ASR_STREAM_URL"),
			runtime_asr_realtime_enabled: bool_env("CV_RUNTIME_ASR_REALTIME_ENABLED", false),
			runtime_asr_realtime_url: optional_env("CV_RUNTIME_ASR_REALTIME_URL"),
			runtime_asr_realtime_chunk_duration_ms: u64_env(
			"CV_RUNTIME_ASR_REALTIME_CHUNK_DURATION_MS",
			200,
			),
			runtime_turn_artifact_dir: optional_env("CV_RUNTIME_TURN_ARTIFACT_DIR"),
			runtime_session_nonce: optional_env("CV_RUNTIME_SESSION_NONCE"),
			user_audio_observer_enabled: bool_env("CV_ENABLE_USER_AUDIO_OBSERVER", true),
			@@ -596,10 +1170,36 @@
			"traceId": trace_id,
			"turnId": turn_id,
			"eventName": event_name,
			"eventWallTimeMs": current_time_millis(),
			"result": result,
			"reasonCode": reason_code,
			"retryable": retryable,
			"extension": extension,
			});
			println!("{payload}");
			}

			fn emit_anchored_activity(
			call_id: &str,
			trace_id: &str,
			turn_id: &str,
			event_name: &str,
			marker: &RuntimeTurnStreamTimingMarker,
			extension: serde_json::Value,
			) {
			let payload = json!({
			"type": "cv_activity",
			"callId": call_id,
			"traceId": trace_id,
			"turnId": turn_id,
			"eventName": event_name,
			"eventWallTimeMs": current_time_millis(),
			"serverDeltaMs": marker.server_delta_ms,
			"serverDeltaSource": STREAM_TIMING_SOURCE,
			"result": "ok",
			"reasonCode": null,
			"retryable": null,
			"extension": marker.extension_with(extension),
			});
			println!("{payload}");
			}
			@@ -616,6 +1216,7 @@
			let enabled = config.user_audio_observer_enabled;
			let simple_vad_enabled = config.simple_vad_enabled;
			let simple_vad_config = config.simple_vad_config.clone();
			let user_participant_identity = config.user_participant_identity.clone();
			let turn_bridge_config = TurnBridgeConfig::from_config(config);

			tokio::spawn(async move {
			@@ -637,9 +1238,14 @@
			turn_bridge_config,
			http,
			sink,
			user_participant_identity,
			)
			.await;
			})
			}

			fn is_bound_user_participant(identity: &str, expected: Option<&str>) -> bool {
			expected.is_none_or(\|value\| identity == value)
			}

			async fn observe_user_audio_events(
			@@ -652,6 +1258,7 @@
			turn_bridge_config: TurnBridgeConfig,
			http: Client,
			sink: Arc<BotAudioOutputSink>,
			user_participant_identity: Option<String>,
			) {
			info!(
			call_id = %call_id,
			@@ -668,6 +1275,11 @@
			"runtime helper user_track_subscribe_requested"
			);

			let mut current_user_participant: Option<RemoteParticipant> = None;
			let mut pending_probe: Option<PendingControlledFixtureProbe> = None;
			let mut acknowledged_probe_sequences = HashSet::new();
			let controlled_fixture_lifecycle_active = Arc::new(AtomicBool::new(true));

			while let Some(event) = events.recv().await {
			match event {
			RoomEvent::TrackSubscribed {
			@@ -675,6 +1287,15 @@
			publication: _,
			participant,
			} => {
			if !is_bound_user_participant(
			&participant.identity().to_string(),
			user_participant_identity.as_deref(),
			) {
			warn!(call_id = %call_id, trace_id = %trace_id,
			metadata_status = "wrong_participant",
			"runtime helper ignored non-user audio participant");
			continue;
			}
			let participant_alias = redact(&participant.identity().to_string());
			let track_sid_alias = redact(&track.sid().to_string());
			let track_name = track.name();
			@@ -688,19 +1309,130 @@
			track_source = %track_source,
			"runtime helper user_track_subscribed"
			);
			spawn_user_audio_frame_observer(
			track,
			call_id.clone(),
			trace_id.clone(),
			participant_alias,
			track_sid_alias,
			simple_vad_enabled,
			simple_vad_config.clone(),
			vad_enabled_gate.clone(),
			turn_bridge_config.clone(),
			http.clone(),
			sink.clone(),
			let pending_binding = pending_probe.clone();
			let participant_for_probe = participant.clone();
			let probe_result = process_controlled_fixture_probe(
			&mut pending_probe,
			&mut acknowledged_probe_sequences,
			Some(&participant_for_probe),
			&sink,
			user_participant_identity.as_deref(),
			&call_id,
			&trace_id,
			controlled_fixture_lifecycle_active.clone(),
			)
			.await;
			let observer_started = start_observer_after_controlled_fixture_probe(
			pending_binding.is_some(),
			probe_result,
			\|\| {
			spawn_user_audio_frame_observer(
			track,
			call_id.clone(),
			trace_id.clone(),
			participant_alias,
			track_sid_alias,
			simple_vad_enabled,
			simple_vad_config.clone(),
			vad_enabled_gate.clone(),
			turn_bridge_config.clone(),
			http.clone(),
			sink.clone(),
			user_participant_identity.clone(),
			participant,
			);
			},
			);
			if let Some(probe) = pending_binding.as_ref() {
			let (ack_result, reject_reason, observed) = match probe_result {
			Some(true) => (Some("observed"), None, true),
			Some(false) => (Some("rejected"), Some("unknown"), false),
			None => (None, Some("no_current_participant"), false),
			};
			record_controlled_fixture_probe_event(
			&call_id,
			&trace_id,
			if observer_started {
			"audio_observer_allowed"
			} else {
			"audio_observer_blocked"
			},
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			observed,
			ack_result,
			reject_reason,
			);
			}
			if !observer_started {
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			"runtime helper withheld audio observer until controlled fixture ACK"
			);
			continue;
			}
			current_user_participant = Some(participant_for_probe);
			}
			RoomEvent::DataReceived {
			payload,
			topic: Some(topic),
			participant: Some(sender),
			..
			} if topic == CONTROLLED_FIXTURE_PROBE_TOPIC => {
			if let Ok(probe) =
			serde_json::from_slice::<ControlledFixtureAttributeProbe>(&payload)
			{
			if acknowledged_probe_sequences.contains(&probe.client_fixture_sequence) {
			record_controlled_fixture_probe_event(
			&call_id,
			&trace_id,
			"data_received",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.client_fixture_sequence,
			false,
			Some("rejected"),
			Some("duplicate_or_old_sequence"),
			);
			continue;
			}
			}
			pending_probe = controlled_fixture_probe(
			&payload,
			&call_id,
			&trace_id,
			&sender.identity(),
			user_participant_identity.as_deref(),
			);
			if let Some(probe) = pending_probe.as_ref() {
			record_controlled_fixture_probe_event(
			&call_id,
			&trace_id,
			"data_received",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			false,
			None,
			None,
			);
			}
			process_controlled_fixture_probe(
			&mut pending_probe,
			&mut acknowledged_probe_sequences,
			current_user_participant.as_ref(),
			&sink,
			user_participant_identity.as_deref(),
			&call_id,
			&trace_id,
			controlled_fixture_lifecycle_active.clone(),
			)
			.await;
			}
			RoomEvent::TrackSubscribed {
			track: RemoteTrack::Video(track),
			@@ -741,6 +1473,149 @@
			_ => {}
			}
			}
			controlled_fixture_lifecycle_active.store(false, Ordering::Release);
			}

			async fn process_controlled_fixture_probe(
			pending_probe: &mut Option<PendingControlledFixtureProbe>,
			acknowledged_probe_sequences: &mut HashSet<String>,
			participant: Option<&RemoteParticipant>,
			sink: &BotAudioOutputSink,
			expected_participant: Option<&str>,
			runtime_call_id: &str,
			runtime_trace_id: &str,
			lifecycle_active: Arc<AtomicBool>,
			) -> Option<bool> {
			let Some(probe) = pending_probe.take() else {
			return None;
			};
			if acknowledged_probe_sequences.contains(&probe.sequence) {
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"attributes_classified",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			false,
			Some("rejected"),
			Some("duplicate_or_old_sequence"),
			);
			return Some(false);
			}
			if Instant::now() > probe.expires_at {
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"attributes_classified",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			false,
			Some("timeout"),
			Some("expired"),
			);
			return Some(false);
			}
			let Some(participant) = participant else {
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"attributes_classified",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			false,
			None,
			Some("no_current_participant"),
			);
			*pending_probe = Some(probe);
			return None;
			};
			if participant.identity() != probe.sender {
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"attributes_classified",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			false,
			Some("rejected"),
			Some("wrong_participant"),
			);
			return Some(false);
			}
			let decision = observe_controlled_fixture_attributes(
			probe.expires_at,
			&participant.identity().to_string(),
			expected_participant,
			&probe.sequence,
			\|\| participant.attributes(),
			)
			.await;
			let (ack_result, reject_reason, observed) = record_controlled_fixture_attribute_decision(
			decision,
			runtime_call_id,
			runtime_trace_id,
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			);
			let ack = controlled_fixture_ack_from_probe(&probe, observed, reject_reason);
			let payload = match serde_json::to_vec(&ack) {
			Ok(payload) => payload,
			Err(_) => return Some(false),
			};
			let local_participant = sink.room.local_participant();
			record_controlled_fixture_probe_event(
			runtime_call_id,
			runtime_trace_id,
			"ack_publish_started",
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			observed,
			Some(ack_result),
			reject_reason,
			);
			let publish = local_participant.publish_data(DataPacket {
			payload,
			topic: Some(CONTROLLED_FIXTURE_ACK_TOPIC.to_string()),
			reliable: true,
			destination_identities: vec![probe.sender.clone()],
			});
			let outcome = complete_controlled_fixture_ack_publish(
			publish,
			runtime_call_id,
			runtime_trace_id,
			observed,
			ack_result,
			reject_reason,
			&probe.call_id_hash,
			&probe.call_trace_id_hash,
			probe.generation,
			&probe.sequence,
			acknowledged_probe_sequences,
			)
			.await;
			if outcome.published && ack_result == "timeout" && reject_reason == Some("expired") {
			spawn_controlled_fixture_post_expiry_observation(
			probe,
			participant.clone(),
			expected_participant.map(str::to_string),
			lifecycle_active,
			runtime_call_id.to_string(),
			runtime_trace_id.to_string(),
			);
			}
			Some(outcome.observed)
			}

			async fn handle_finished_turn(
			@@ -750,6 +1625,7 @@
			call_id: &str,
			trace_id: &str,
			turn: FinishedSpeechTurn,
			realtime_asr_result_ref: Option<String>,
			) {
			let turn_pipeline_started_at = Instant::now();
			if !bridge_config.is_ready() {
			@@ -806,9 +1682,13 @@
			"turnArtifactBytes": byte_size,
			"frameCount": turn.frame_count,
			"sampleCount": turn.sample_count,
			"endReason": turn.end_reason,
			"endReason": turn.end_reason.as_str(),
			}),
			);
			let asr_result_ref = match realtime_asr_result_ref {
			Some(value) => Some(value),
			None => request_asr_result_ref(http, bridge_config, call_id, trace_id, &turn).await,
			};
			if bridge_config.is_stream_mode() {
			match request_turn_bridge_stream(
			http,
			@@ -819,6 +1699,7 @@
			&turn,
			&path_ref,
			byte_size,
			asr_result_ref.as_deref(),
			turn_pipeline_started_at,
			)
			.await
			@@ -882,12 +1763,17 @@
			&turn,
			&path_ref,
			byte_size,
			asr_result_ref.as_deref(),
			turn_pipeline_started_at,
			)
			.await
			{
			Ok(outcome) => {
			let mut published_device_outputs = HashSet::new();
			for output in &outcome.device_outputs {
			if !should_publish_device_output(&mut published_device_outputs, output) {
			continue;
			}
			if let Err(error) = sink
			.publish_device_output(call_id, trace_id, &turn.turn_id, output)
			.await
			@@ -1003,6 +1889,251 @@
			Ok((path_ref, byte_size))
			}

			async fn request_asr_result_ref(
			http: &Client,
			bridge_config: &TurnBridgeConfig,
			call_id: &str,
			trace_id: &str,
			turn: &FinishedSpeechTurn,
			) -> Option<String> {
			if !bridge_config.is_asr_stream_ready() {
			return None;
			}
			match request_asr_stream(http, bridge_config, call_id, trace_id, turn).await {
			Ok(Some(asr_result_ref)) => {
			emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"asr_stream_ref_ready",
			"ok",
			None,
			None,
			json!({
			"asrResultRefPresent": true,
			"format": "pcm_s16le",
			"sampleRate": 16000,
			"channels": 1,
			}),
			);
			Some(asr_result_ref)
			}
			Ok(None) => None,
			Err(error) => {
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			turn_id = %turn.turn_id,
			error = %safe_error(&error.to_string()),
			"runtime helper asr_stream_failed_fallback"
			);
			emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"asr_stream_fallback",
			"skipped",
			Some("ASR_STREAM_INTERRUPTED"),
			Some(true),
			json!({
			"fallbackReason": "asr_stream_request_failed",
			"fallbackStage": "asr_stream",
			}),
			);
			None
			}
			}
			}

			async fn request_asr_stream(
			http: &Client,
			bridge_config: &TurnBridgeConfig,
			call_id: &str,
			trace_id: &str,
			turn: &FinishedSpeechTurn,
			) -> Result<Option<String>> {
			let started_at = Instant::now();
			let ndjson = build_asr_stream_ndjson(call_id, trace_id, turn, bridge_config)?;
			let response = http
			.post(bridge_config.asr_stream_url.as_deref().unwrap_or_default())
			.header("Content-Type", "application/x-ndjson")
			.header(
			"X-CV-Runtime-Token",
			bridge_config.bridge_token.as_deref().unwrap_or_default(),
			)
			.header("X-CV-Call-Id", call_id)
			.header("X-CV-Trace-Id", trace_id)
			.header(
			"X-CV-Runtime-Session-Nonce",
			bridge_config
			.runtime_session_nonce
			.as_deref()
			.unwrap_or_default(),
			)
			.body(ndjson)
			.send()
			.await
			.context("failed to post asr stream")?;
			let status = response.status();
			if !status.is_success() {
			let body_len = response.text().await.map(\|body\| body.len()).unwrap_or(0);
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			turn_id = %turn.turn_id,
			http_status = status.as_u16(),
			body_len,
			"runtime helper asr_stream_http_failed"
			);
			return Ok(None);
			}
			let body: RuntimeTurnCommonResult<RuntimeAsrStreamResp> = response
			.json()
			.await
			.context("failed to decode asr stream response")?;
			if body.code != 0 {
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			turn_id = %turn.turn_id,
			code = body.code,
			msg_len = body.msg.as_deref().unwrap_or_default().len(),
			"runtime helper asr_stream_common_result_failed"
			);
			return Ok(None);
			}
			let Some(data) = body.data else {
			return Ok(None);
			};
			if data.status.as_deref() == Some("final") {
			info!(
			call_id = %call_id,
			trace_id = %trace_id,
			turn_id = %turn.turn_id,
			chunk_count = data.chunk_count.unwrap_or_default(),
			audio_bytes = data.audio_bytes.unwrap_or_default(),
			asr_duration_ms = data.asr_duration_ms.unwrap_or_default(),
			wall_ms = started_at.elapsed().as_millis() as u64,
			provider = %data.provider_alias.as_deref().unwrap_or("unknown"),
			text_len = data.text_len.unwrap_or_default(),
			"runtime helper asr_stream_final"
			);
			return Ok(data.asr_result_ref);
			}
			emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"asr_stream_fallback",
			"skipped",
			None,
			Some(true),
			json!({
			"fallbackReason": data.fallback_reason,
			"fallbackStage": data.fallback_stage,
			"status": data.status,
			}),
			);
			Ok(None)
			}

			fn build_asr_stream_ndjson(
			call_id: &str,
			trace_id: &str,
			turn: &FinishedSpeechTurn,
			bridge_config: &TurnBridgeConfig,
			) -> Result<String> {
			let chunks = asr_pcm_16k_chunks(turn)?;
			let mut seq = 1u64;
			let mut lines = Vec::with_capacity(chunks.len() + 3);
			lines.push(serde_json::to_string(&json!({
			"event": "asr_stream_started",
			"seq": seq,
			"callId": call_id,
			"traceId": trace_id,
			"turnId": turn.turn_id.as_str(),
			"tsMs": current_time_millis(),
			"payload": {
			"format": "pcm_s16le",
			"sampleRate": 16000,
			"channels": 1,
			"runtimeSessionNonce": bridge_config.runtime_session_nonce.as_deref().unwrap_or_default(),
			"providerHint": "volcengine",
			}
			}))?);
			for (index, samples) in chunks.iter().enumerate() {
			seq += 1;
			let bytes = pcm_i16_to_le_bytes(samples);
			let duration_ms = ((samples.len() as u64) * 1000 / 16_000).max(1);
			lines.push(serde_json::to_string(&json!({
			"event": "asr_audio_chunk",
			"seq": seq,
			"callId": call_id,
			"traceId": trace_id,
			"turnId": turn.turn_id.as_str(),
			"tsMs": current_time_millis(),
			"payload": {
			"chunkSeq": index + 1,
			"format": "pcm_s16le",
			"sampleRate": 16000,
			"channels": 1,
			"durationMs": duration_ms,
			"payloadBase64": general_purpose::STANDARD.encode(bytes),
			}
			}))?);
			}
			seq += 1;
			lines.push(serde_json::to_string(&json!({
			"event": "vad_speech_end",
			"seq": seq,
			"callId": call_id,
			"traceId": trace_id,
			"turnId": turn.turn_id.as_str(),
			"tsMs": current_time_millis(),
			"payload": {
			"endReason": turn.end_reason.as_str(),
			"speechDurationMs": turn.duration_ms,
			}
			}))?);
			seq += 1;
			lines.push(serde_json::to_string(&json!({
			"event": "asr_stream_finish",
			"seq": seq,
			"callId": call_id,
			"traceId": trace_id,
			"turnId": turn.turn_id.as_str(),
			"tsMs": current_time_millis(),
			"payload": {
			"finalChunkSeq": chunks.len(),
			"audioDurationMs": turn.duration_ms,
			}
			}))?);
			Ok(lines.join("\n") + "\n")
			}

			fn asr_pcm_16k_chunks(turn: &FinishedSpeechTurn) -> Result<Vec<Vec<i16>>> {
			if turn.samples.is_empty() {
			return Err(anyhow!("empty turn samples"));
			}
			let samples_16k: Vec<i16> = turn.samples.iter().step_by(3).copied().collect();
			if samples_16k.is_empty() {
			return Err(anyhow!("empty 16k asr samples"));
			}
			let samples_per_chunk = 320usize;
			Ok(samples_16k
			.chunks(samples_per_chunk)
			.map(\|chunk\| chunk.to_vec())
			.collect())
			}

			fn pcm_i16_to_le_bytes(samples: &[i16]) -> Vec<u8> {
			let mut bytes = Vec::with_capacity(samples.len() * 2);
			for sample in samples {
			bytes.extend_from_slice(&sample.to_le_bytes());
			}
			bytes
			}

			async fn request_turn_bridge_stream(
			http: &Client,
			bridge_config: &TurnBridgeConfig,
			@@ -1012,6 +2143,7 @@
			turn: &FinishedSpeechTurn,
			path_ref: &str,
			byte_size: u64,
			asr_result_ref: Option<&str>,
			turn_pipeline_started_at: Instant,
			) -> Result<RuntimeTurnStreamOutcome> {
			let bridge_started_at = Instant::now();
			@@ -1019,7 +2151,7 @@
			call_id: call_id.to_string(),
			trace_id: trace_id.to_string(),
			turn_id: turn.turn_id.clone(),
			audio_artifact: RuntimeTurnAudioArtifact {
			audio_artifact: Some(RuntimeTurnAudioArtifact {
			artifact_type: "local_file".to_string(),
			path_ref: path_ref.to_string(),
			format: "wav".to_string(),
			@@ -1027,7 +2159,8 @@
			channels: u32::from(USER_AUDIO_NUM_CHANNELS),
			duration_ms: turn.duration_ms,
			byte_size,
			},
			}),
			asr_result_ref: asr_result_ref.map(str::to_string),
			};
			let response = http
			.post(bridge_config.bridge_url.as_deref().unwrap_or_default())
			@@ -1106,6 +2239,7 @@
			.await?;
			}
			}
			state.close_timing();
			if !state.completed {
			warn!(
			call_id = %call_id,
			@@ -1235,6 +2369,7 @@
			call_id,
			trace_id,
			turn,
			&event,
			audio_chunk,
			state,
			turn_pipeline_started_at,
			@@ -1246,6 +2381,9 @@
			}
			Some("device_output") => {
			if let Some(output) = event.device_output.as_ref() {
			if !should_publish_device_output(&mut state.published_device_output_ids, output) {
			return Ok(());
			}
			sink.publish_device_output(call_id, trace_id, &turn.turn_id, output)
			.await?;
			state.device_output_count = state.device_output_count.saturating_add(1);
			@@ -1253,6 +2391,7 @@
			}
			Some("turn_completed") => {
			state.completed = true;
			state.close_timing();
			info!(
			call_id = %call_id,
			trace_id = %trace_id,
			@@ -1263,6 +2402,7 @@
			);
			}
			Some("turn_failed") => {
			state.close_timing();
			let error = event.error.as_ref();
			let reason_code = error
			.and_then(\|value\| value.reason_code.as_deref())
			@@ -1297,6 +2437,7 @@
			}
			Some("turn_cancelled") => {
			state.completed = true;
			state.close_timing();
			info!(
			call_id = %call_id,
			trace_id = %trace_id,
			@@ -1329,6 +2470,19 @@
			}
			Some("activity") => {
			if let Some(activity) = event.activity.as_ref() {
			if activity.event_type.as_deref() == Some("tts_first_audio_chunk_ready") {
			if let Some(runtime_session_nonce) =
			bridge_config.runtime_session_nonce.as_deref()
			{
			let _ = state.arm_timing_anchor(
			call_id,
			trace_id,
			&turn.turn_id,
			runtime_session_nonce,
			&event,
			);
			}
			}
			info!(
			call_id = %call_id,
			trace_id = %trace_id,
			@@ -1387,6 +2541,7 @@
			call_id: &str,
			trace_id: &str,
			turn: &FinishedSpeechTurn,
			event: &RuntimeTurnStreamEvent,
			audio_chunk: &RuntimeTurnStreamAudioChunk,
			state: &mut RuntimeTurnStreamState,
			turn_pipeline_started_at: Instant,
			@@ -1406,6 +2561,58 @@
			.unwrap_or("pcm_s16le")
			.trim()
			.to_ascii_lowercase();
			if !matches!(format.as_str(), "pcm_s16le" \| "mp3" \| "mpeg" \| "wav") {
			return Err(anyhow!("unsupported reply_audio_chunk format {format}"));
			}
			match state.reply_chunk_markers.observe(audio_chunk.segment_seq) {
			ReplyChunkMarker::FirstReply => {
			let extension = json!({
			"segmentSeq": audio_chunk.segment_seq,
			"chunkSeq": audio_chunk.chunk_seq,
			"format": format.as_str(),
			"bytes": payload.len(),
			});
			if let Some(marker) =
			state.record_m6(call_id, trace_id, &turn.turn_id, event, audio_chunk)
			{
			emit_anchored_activity(
			call_id,
			trace_id,
			&turn.turn_id,
			"helper_first_reply_audio_chunk_received",
			&marker,
			extension,
			);
			} else {
			emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"helper_first_reply_audio_chunk_received",
			"ok",
			None,
			None,
			extension,
			);
			}
			}
			ReplyChunkMarker::SegmentFirst => emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"helper_segment_first_audio_chunk_received",
			"ok",
			None,
			None,
			json!({
			"segmentSeq": audio_chunk.segment_seq,
			"chunkSeq": audio_chunk.chunk_seq,
			"format": format.as_str(),
			"bytes": payload.len(),
			}),
			),
			ReplyChunkMarker::None => {}
			}
			let frames = if format == "pcm_s16le" {
			let sample_rate = audio_chunk.sample_rate.unwrap_or(sink.sample_rate_hz);
			let channels = audio_chunk.channels.unwrap_or(u32::from(sink.num_channels));
			@@ -1497,7 +2704,7 @@
			Err(error) => return Err(error).context("failed to decode final stream audio chunk"),
			}
			} else {
			return Err(anyhow!("unsupported reply_audio_chunk format {format}"));
			unreachable!("supported encoded format checked above")
			};
			if frames.is_empty() {
			return Ok(0);
			@@ -1525,21 +2732,33 @@
			sink.write_pcm_frame(frame).await?;
			if !state.first_audio_frame_written {
			state.first_audio_frame_written = true;
			emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"bot_reply_first_audio_frame_written",
			"ok",
			None,
			None,
			json!({
			"replyPlaybackMode": state.reply_playback_mode.as_str(),
			"format": format.as_str(),
			"chunkSeq": audio_chunk.chunk_seq,
			"replyTotalAfterVadEndMs": turn_pipeline_started_at.elapsed().as_millis() as u64,
			}),
			);
			let extension = json!({
			"replyPlaybackMode": state.reply_playback_mode.as_str(),
			"format": format.as_str(),
			"chunkSeq": audio_chunk.chunk_seq,
			"replyTotalAfterVadEndMs": turn_pipeline_started_at.elapsed().as_millis() as u64,
			});
			if let Some(marker) = state.record_m7() {
			emit_anchored_activity(
			call_id,
			trace_id,
			&turn.turn_id,
			"bot_reply_first_audio_frame_written",
			&marker,
			extension,
			);
			} else {
			emit_activity(
			call_id,
			trace_id,
			Some(&turn.turn_id),
			"bot_reply_first_audio_frame_written",
			"ok",
			None,
			None,
			extension,
			);
			}
			}
			sleep_until(pacing_started_at + Duration::from_millis(((index + 1) as u64) * 20)).await;
			}
			@@ -1620,6 +2839,7 @@
			turn: &FinishedSpeechTurn,
			path_ref: &str,
			byte_size: u64,
			asr_result_ref: Option<&str>,
			turn_pipeline_started_at: Instant,
			) -> Result<RuntimeTurnBridgeOutcome> {
			let bridge_started_at = Instant::now();
			@@ -1627,7 +2847,7 @@
			call_id: call_id.to_string(),
			trace_id: trace_id.to_string(),
			turn_id: turn.turn_id.clone(),
			audio_artifact: RuntimeTurnAudioArtifact {
			audio_artifact: Some(RuntimeTurnAudioArtifact {
			artifact_type: "local_file".to_string(),
			path_ref: path_ref.to_string(),
			format: "wav".to_string(),
			@@ -1635,7 +2855,8 @@
			channels: u32::from(USER_AUDIO_NUM_CHANNELS),
			duration_ms: turn.duration_ms,
			byte_size,
			},
			}),
			asr_result_ref: asr_result_ref.map(str::to_string),
			};
			let response = http
			.post(bridge_config.bridge_url.as_deref().unwrap_or_default())
			@@ -1926,7 +3147,10 @@
			#[serde(rename = "turnId")]
			turn_id: String,
			#[serde(rename = "audioArtifact")]
			audio_artifact: RuntimeTurnAudioArtifact,
			#[serde(skip_serializing_if = "Option::is_none")]
			audio_artifact: Option<RuntimeTurnAudioArtifact>,
			#[serde(rename = "asrResultRef", skip_serializing_if = "Option::is_none")]
			asr_result_ref: Option<String>,
			}

			#[derive(Serialize)]
			@@ -1954,6 +3178,20 @@
			retryable: Option<bool>,
			}

			#[derive(Deserialize)]
			#[serde(rename_all = "camelCase")]
			struct RuntimeAsrStreamResp {
			status: Option<String>,
			asr_result_ref: Option<String>,
			chunk_count: Option<u64>,
			audio_bytes: Option<u64>,
			asr_duration_ms: Option<u64>,
			provider_alias: Option<String>,
			text_len: Option<u64>,
			fallback_reason: Option<String>,
			fallback_stage: Option<String>,
			}

			#[derive(Default)]
			struct RuntimeTurnBridgeOutcome {
			reply_audio_artifact: Option<RuntimeTurnReplyAudioArtifact>,
			@@ -1974,9 +3212,12 @@
			completed: bool,
			audio_chunk_count: u64,
			device_output_count: u64,
			published_device_output_ids: HashSet<String>,
			encoded_audio_buffer: Vec<u8>,
			pcm_stream_decoder: Option<audio::PcmS16leStreamDecoder>,
			pcm_stream_network_chunk_count: u64,
			reply_chunk_markers: ReplyChunkMarkerState,
			timing: RuntimeTurnStreamTimingState,
			}

			impl Default for RuntimeTurnStreamState {
			@@ -1989,10 +3230,266 @@
			completed: false,
			audio_chunk_count: 0,
			device_output_count: 0,
			published_device_output_ids: HashSet::new(),
			encoded_audio_buffer: Vec::new(),
			pcm_stream_decoder: None,
			pcm_stream_network_chunk_count: 0,
			reply_chunk_markers: ReplyChunkMarkerState::default(),
			timing: RuntimeTurnStreamTimingState::default(),
			}
			}
			}

			impl RuntimeTurnStreamState {
			fn arm_timing_anchor(
			&mut self,
			call_id: &str,
			trace_id: &str,
			turn_id: &str,
			runtime_session_nonce: &str,
			event: &RuntimeTurnStreamEvent,
			) -> bool {
			if self.timing.phase != RuntimeTurnStreamTimingPhase::Empty
			\|\| event.call_id.as_deref() != Some(call_id)
			\|\| event.trace_id.as_deref() != Some(trace_id)
			\|\| event.turn_id.as_deref() != Some(turn_id)
			{
			return false;
			}
			let Some(activity) = event.activity.as_ref() else {
			return false;
			};
			if activity.event_type.as_deref() != Some("tts_first_audio_chunk_ready") {
			return false;
			}
			let Some(extension) = activity.extension.as_ref() else {
			return false;
			};
			let Some(anchor_id) = extension.stream_anchor_id.as_deref() else {
			return false;
			};
			let valid_anchor_id = (16..=64).contains(&anchor_id.len()) && anchor_id.is_ascii();
			let expected_nonce_hash = runtime_session_nonce_hash(runtime_session_nonce);
			if extension.stream_timing_version != Some(STREAM_TIMING_VERSION)
			\|\| !valid_anchor_id
			\|\| extension.runtime_session_nonce_hash.as_deref() != Some(expected_nonce_hash.as_str())
			\|\| extension.segment_seq != Some(STREAM_TIMING_FIRST_SEGMENT)
			\|\| extension.stream_timing_validation.as_deref() != Some("bound")
			{
			return false;
			}
			let Some(server_delta_ms) = extension.stream_anchor_server_delta_ms else {
			return false;
			};
			self.timing.anchor = Some(RuntimeTurnStreamTimingAnchor {
			call_id: call_id.to_string(),
			trace_id: trace_id.to_string(),
			turn_id: turn_id.to_string(),
			anchor_id: anchor_id.to_string(),
			server_delta_ms,
			runtime_session_nonce_hash: expected_nonce_hash,
			segment_seq: STREAM_TIMING_FIRST_SEGMENT,
			received_at: Instant::now(),
			});
			self.timing.phase = RuntimeTurnStreamTimingPhase::Armed;
			true
			}

			fn record_m6(
			&mut self,
			call_id: &str,
			trace_id: &str,
			turn_id: &str,
			event: &RuntimeTurnStreamEvent,
			audio_chunk: &RuntimeTurnStreamAudioChunk,
			) -> Option<RuntimeTurnStreamTimingMarker> {
			if self.timing.phase != RuntimeTurnStreamTimingPhase::Armed {
			return None;
			}
			let anchor = self.timing.anchor.as_ref()?;
			if anchor.call_id != call_id
			\|\| anchor.trace_id != trace_id
			\|\| anchor.turn_id != turn_id
			\|\| event.call_id.as_deref() != Some(call_id)
			\|\| event.trace_id.as_deref() != Some(trace_id)
			\|\| event.turn_id.as_deref() != Some(turn_id)
			\|\| audio_chunk.segment_seq != Some(anchor.segment_seq)
			\|\| audio_chunk.chunk_seq != Some(STREAM_TIMING_FIRST_CHUNK)
			\|\| audio_chunk.stream_timing_version != Some(STREAM_TIMING_VERSION)
			\|\| audio_chunk.stream_anchor_id.as_deref() != Some(anchor.anchor_id.as_str())
			{
			return None;
			}
			let Some(marker) = RuntimeTurnStreamTimingMarker::from_anchor(
			anchor,
			audio_chunk.chunk_seq.unwrap_or(STREAM_TIMING_FIRST_CHUNK),
			) else {
			self.close_timing();
			return None;
			};
			self.timing.chunk_seq = Some(marker.chunk_seq);
			self.timing.phase = RuntimeTurnStreamTimingPhase::M6Recorded;
			Some(marker)
			}

			fn record_m7(&mut self) -> Option<RuntimeTurnStreamTimingMarker> {
			if self.timing.phase != RuntimeTurnStreamTimingPhase::M6Recorded {
			return None;
			}
			let anchor = self.timing.anchor.as_ref()?;
			let Some(marker) = RuntimeTurnStreamTimingMarker::from_anchor(
			anchor,
			self.timing.chunk_seq.unwrap_or(STREAM_TIMING_FIRST_CHUNK),
			) else {
			self.close_timing();
			return None;
			};
			self.timing.phase = RuntimeTurnStreamTimingPhase::M7Recorded;
			Some(marker)
			}

			fn close_timing(&mut self) {
			self.timing.close();
			}
			}

			#[derive(Debug, Clone, Copy, PartialEq, Eq)]
			enum RuntimeTurnStreamTimingPhase {
			Empty,
			Armed,
			M6Recorded,
			M7Recorded,
			Closed,
			}

			struct RuntimeTurnStreamTimingState {
			phase: RuntimeTurnStreamTimingPhase,
			anchor: Option<RuntimeTurnStreamTimingAnchor>,
			chunk_seq: Option<u64>,
			}

			impl Default for RuntimeTurnStreamTimingState {
			fn default() -> Self {
			Self {
			phase: RuntimeTurnStreamTimingPhase::Empty,
			anchor: None,
			chunk_seq: None,
			}
			}
			}

			impl RuntimeTurnStreamTimingState {
			fn close(&mut self) {
			self.anchor = None;
			self.chunk_seq = None;
			self.phase = RuntimeTurnStreamTimingPhase::Closed;
			}
			}

			impl Drop for RuntimeTurnStreamTimingState {
			fn drop(&mut self) {
			self.anchor = None;
			self.chunk_seq = None;
			}
			}

			struct RuntimeTurnStreamTimingAnchor {
			call_id: String,
			trace_id: String,
			turn_id: String,
			anchor_id: String,
			server_delta_ms: u64,
			runtime_session_nonce_hash: String,
			segment_seq: u64,
			received_at: Instant,
			}

			struct RuntimeTurnStreamTimingMarker {
			version: u32,
			anchor_id: String,
			anchor_server_delta_ms: u64,
			anchor_elapsed_ms: u64,
			server_delta_ms: u64,
			runtime_session_nonce_hash: String,
			segment_seq: u64,
			chunk_seq: u64,
			}

			impl RuntimeTurnStreamTimingMarker {
			fn from_anchor(anchor: &RuntimeTurnStreamTimingAnchor, chunk_seq: u64) -> Option<Self> {
			let elapsed_ms = u64::try_from(anchor.received_at.elapsed().as_millis()).ok()?;
			if elapsed_ms > STREAM_TIMING_MAX_ELAPSED_MS {
			return None;
			}
			Some(Self {
			version: STREAM_TIMING_VERSION,
			anchor_id: anchor.anchor_id.clone(),
			anchor_server_delta_ms: anchor.server_delta_ms,
			anchor_elapsed_ms: elapsed_ms,
			server_delta_ms: anchor.server_delta_ms.checked_add(elapsed_ms)?,
			runtime_session_nonce_hash: anchor.runtime_session_nonce_hash.clone(),
			segment_seq: anchor.segment_seq,
			chunk_seq,
			})
			}

			fn extension_with(&self, extra: serde_json::Value) -> serde_json::Value {
			let mut extension = match extra {
			serde_json::Value::Object(value) => value,
			_ => serde_json::Map::new(),
			};
			extension.insert("streamTimingVersion".to_string(), json!(self.version));
			extension.insert("streamAnchorId".to_string(), json!(self.anchor_id));
			extension.insert(
			"streamAnchorServerDeltaMs".to_string(),
			json!(self.anchor_server_delta_ms),
			);
			extension.insert("anchorElapsedMs".to_string(), json!(self.anchor_elapsed_ms));
			extension.insert(
			"runtimeSessionNonceHash".to_string(),
			json!(self.runtime_session_nonce_hash),
			);
			extension.insert("segmentSeq".to_string(), json!(self.segment_seq));
			extension.insert("chunkSeq".to_string(), json!(self.chunk_seq));
			extension.insert("streamTimingValidation".to_string(), json!("bound"));
			serde_json::Value::Object(extension)
			}
			}

			fn runtime_session_nonce_hash(value: &str) -> String {
			let digest = Sha256::digest(value.as_bytes());
			digest[..6]
			.iter()
			.map(\|byte\| format!("{byte:02x}"))
			.collect()
			}

			#[derive(Debug, PartialEq, Eq)]
			enum ReplyChunkMarker {
			FirstReply,
			SegmentFirst,
			None,
			}

			#[derive(Default)]
			struct ReplyChunkMarkerState {
			first_reply_seen: bool,
			seen_segments: HashSet<u64>,
			}

			impl ReplyChunkMarkerState {
			fn observe(&mut self, segment_seq: Option<u64>) -> ReplyChunkMarker {
			let first_for_segment = segment_seq
			.map(\|value\| self.seen_segments.insert(value))
			.unwrap_or(false);
			if !self.first_reply_seen {
			self.first_reply_seen = true;
			return ReplyChunkMarker::FirstReply;
			}
			if first_for_segment {
			return ReplyChunkMarker::SegmentFirst;
			}
			ReplyChunkMarker::None
			}
			}

			@@ -2012,6 +3509,12 @@
			struct RuntimeTurnStreamEvent {
			#[serde(rename = "type", alias = "event")]
			event_type: Option<String>,
			#[serde(rename = "callId")]
			call_id: Option<String>,
			#[serde(rename = "traceId")]
			trace_id: Option<String>,
			#[serde(rename = "turnId")]
			turn_id: Option<String>,
			#[serde(rename = "seq")]
			seq: Option<u64>,
			#[serde(rename = "replyPlaybackMode")]
			@@ -2047,6 +3550,12 @@
			struct RuntimeTurnStreamAudioChunk {
			#[serde(rename = "chunkSeq", alias = "seq")]
			chunk_seq: Option<u64>,
			#[serde(rename = "segmentSeq")]
			segment_seq: Option<u64>,
			#[serde(rename = "streamTimingVersion")]
			stream_timing_version: Option<u32>,
			#[serde(rename = "streamAnchorId")]
			stream_anchor_id: Option<String>,
			format: Option<String>,
			#[serde(rename = "sampleRate")]
			sample_rate: Option<u32>,
			@@ -2063,6 +3572,23 @@
			stage: Option<String>,
			#[serde(rename = "reasonCode")]
			reason_code: Option<String>,
			extension: Option<RuntimeTurnStreamTimingExtension>,
			}

			#[derive(Clone, Deserialize)]
			struct RuntimeTurnStreamTimingExtension {
			#[serde(rename = "streamTimingVersion")]
			stream_timing_version: Option<u32>,
			#[serde(rename = "streamAnchorId")]
			stream_anchor_id: Option<String>,
			#[serde(rename = "streamAnchorServerDeltaMs")]
			stream_anchor_server_delta_ms: Option<u64>,
			#[serde(rename = "runtimeSessionNonceHash")]
			runtime_session_nonce_hash: Option<String>,
			#[serde(rename = "segmentSeq")]
			segment_seq: Option<u64>,
			#[serde(rename = "streamTimingValidation")]
			stream_timing_validation: Option<String>,
			}

			#[derive(Deserialize)]
			@@ -2095,6 +3621,30 @@
			#[serde(rename = "commandCode")]
			command_code: Option<String>,
			params: Option<serde_json::Value>,
			}

			fn should_publish_device_output(
			published_ids: &mut HashSet<String>,
			output: &RuntimeTurnDeviceOutput,
			) -> bool {
			let Some(command_id) = output
			.command_id
			.as_deref()
			.map(str::trim)
			.filter(\|value\| !value.is_empty())
			else {
			return false;
			};
			if output
			.command_code
			.as_deref()
			.map(str::trim)
			.filter(\|value\| !value.is_empty())
			.is_none()
			{
			return false;
			}
			published_ids.insert(command_id.to_string())
			}

			fn require_safe_segment(value: &str) -> Result<()> {
			@@ -2136,6 +3686,8 @@
			turn_bridge_config: TurnBridgeConfig,
			http: Client,
			sink: Arc<BotAudioOutputSink>,
			expected_participant_identity: Option<String>,
			participant: RemoteParticipant,
			) -> JoinHandle<()> {
			tokio::spawn(async move {
			let mut stream = NativeAudioStream::new(
			@@ -2144,6 +3696,68 @@
			i32::from(USER_AUDIO_NUM_CHANNELS),
			);
			let started_at = Instant::now();
			let (frame_tx, mut frame_rx) =
			mpsc::channel::<DrainedUserAudioFrame>(INBOUND_AUDIO_QUEUE_CAPACITY);
			let (drain_shutdown_tx, mut drain_shutdown_rx) = watch::channel(false);
			let drain_call_id = call_id.clone();
			let drain_trace_id = trace_id.clone();
			let drain_task = tokio::spawn(async move {
			let mut received_frame_count: u64 = 0;
			let mut dropped_frame_count: u64 = 0;
			loop {
			tokio::select! {
			changed = drain_shutdown_rx.changed() => {
			match changed {
			Ok(()) if *drain_shutdown_rx.borrow() => break,
			Ok(()) => {}
			Err(_) => break,
			}
			}
			maybe_frame = stream.next() => {
			let Some(frame) = maybe_frame else {
			break;
			};
			received_frame_count = received_frame_count.saturating_add(1);
			let drained = DrainedUserAudioFrame {
			frame_index: received_frame_count,
			captured_elapsed_ms: started_at.elapsed().as_millis() as u64,
			frame: AudioFrame {
			data: Cow::Owned(frame.data.as_ref().to_vec()),
			sample_rate: frame.sample_rate,
			num_channels: frame.num_channels,
			samples_per_channel: frame.samples_per_channel,
			},
			};
			match frame_tx.try_send(drained) {
			Ok(()) => {}
			Err(mpsc::error::TrySendError::Full(_)) => {
			dropped_frame_count = dropped_frame_count.saturating_add(1);
			if dropped_frame_count % INBOUND_AUDIO_DROP_LOG_INTERVAL == 1 {
			warn!(
			call_id = %drain_call_id,
			trace_id = %drain_trace_id,
			dropped_frame_count,
			received_frame_count,
			queue_capacity = INBOUND_AUDIO_QUEUE_CAPACITY,
			"runtime helper inbound_audio_queue_full_dropping_newest"
			);
			}
			}
			Err(mpsc::error::TrySendError::Closed(_)) => break,
			}
			}
			}
			}
			stream.close();
			info!(
			call_id = %drain_call_id,
			trace_id = %drain_trace_id,
			received_frame_count,
			dropped_frame_count,
			queue_capacity = INBOUND_AUDIO_QUEUE_CAPACITY,
			"runtime helper user_audio_drain_ended"
			);
			});
			let mut frame_count: u64 = 0;
			let mut sample_count: u64 = 0;
			let mut simple_vad = if simple_vad_enabled {
			@@ -2151,11 +3765,14 @@
			} else {
			None
			};
			let mut realtime_asr_upload: Option<RealtimeAsrUpload> = None;
			let mut last_fixture_sequence: Option<String> = None;

			while let Some(frame) = stream.next().await {
			frame_count += 1;
			while let Some(drained) = frame_rx.recv().await {
			let frame = drained.frame;
			frame_count = drained.frame_index;
			sample_count += u64::from(frame.samples_per_channel) * u64::from(frame.num_channels);
			let elapsed_ms = started_at.elapsed().as_millis() as u64;
			let elapsed_ms = drained.captured_elapsed_ms;
			if frame_count == 1 {
			info!(
			call_id = %call_id,
			@@ -2183,7 +3800,11 @@

			if let Some(vad) = simple_vad.as_mut() {
			if vad_enabled_gate.load(Ordering::Acquire) {
			if let Some(turn) = vad.observe_frame(
			let participant_identity = participant.identity().to_string();
			let (was_in_speech, is_in_speech, turn) = observe_bound_participant_frame(
			&participant_identity,
			expected_participant_identity.as_deref(),
			vad,
			&call_id,
			&trace_id,
			&participant_alias,
			@@ -2191,7 +3812,40 @@
			frame_count,
			elapsed_ms,
			&frame,
			) {
			http.clone(),
			turn_bridge_config.realtime_asr_config(),
			\|\| participant.attributes(),
			&mut realtime_asr_upload,
			&mut last_fixture_sequence,
			turn_bridge_config.asr_realtime_enabled,
			);

			if was_in_speech {
			let push_failed = realtime_asr_upload
			.as_mut()
			.and_then(\|upload\| upload.push_48k_samples(frame.data.as_ref()).err());
			if let Some(error) = push_failed {
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			error = %safe_error(&error.to_string()),
			"runtime helper asr_realtime_upload_failed_fallback"
			);
			if let Some(upload) = realtime_asr_upload.take() {
			tokio::spawn(async move {
			upload.cancel("upload_backpressure").await;
			});
			}
			}
			}

			if let Some(turn) = turn {
			let realtime_asr_result_ref = match realtime_asr_upload.take() {
			Some(upload) => {
			finish_realtime_asr_upload(upload, &call_id, &trace_id, &turn).await
			}
			None => None,
			};
			handle_finished_turn(
			&http,
			&turn_bridge_config,
			@@ -2199,10 +3853,22 @@
			&call_id,
			&trace_id,
			turn,
			realtime_asr_result_ref,
			)
			.await;
			} else if was_in_speech && !is_in_speech {
			if let Some(upload) = realtime_asr_upload.take() {
			tokio::spawn(async move {
			upload.cancel("speech_too_short").await;
			});
			}
			}
			} else {
			if let Some(upload) = realtime_asr_upload.take() {
			tokio::spawn(async move {
			upload.cancel("vad_disabled").await;
			});
			}
			vad.observe_disabled_frame(
			&call_id,
			&trace_id,
			@@ -2223,9 +3889,41 @@
			&track_sid_alias,
			started_at.elapsed().as_millis() as u64,
			) {
			handle_finished_turn(&http, &turn_bridge_config, &sink, &call_id, &trace_id, turn)
			.await;
			let realtime_asr_result_ref = match realtime_asr_upload.take() {
			Some(upload) => {
			finish_realtime_asr_upload(upload, &call_id, &trace_id, &turn).await
			}
			None => None,
			};
			handle_finished_turn(
			&http,
			&turn_bridge_config,
			&sink,
			&call_id,
			&trace_id,
			turn,
			realtime_asr_result_ref,
			)
			.await;
			}
			}
			if let Some(upload) = realtime_asr_upload.take() {
			upload.cancel("stream_end").await;
			}
			let _ = drain_shutdown_tx.send(true);
			let mut drain_task = drain_task;
			if timeout(AUDIO_DRAIN_STOP_GRACE, &mut drain_task)
			.await
			.is_err()
			{
			drain_task.abort();
			let _ = drain_task.await;
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			stop_grace_ms = AUDIO_DRAIN_STOP_GRACE.as_millis() as u64,
			"runtime helper user_audio_drain_stop_timeout"
			);
			}

			info!(
			@@ -2239,6 +3937,234 @@
			"runtime helper user_audio_stream_ended"
			);
			})
			}

			fn observe_frame_and_start_session<F>(
			vad: &mut SimpleVad,
			call_id: &str,
			trace_id: &str,
			participant_alias: &str,
			track_sid_alias: &str,
			frame_count: u64,
			elapsed_ms: u64,
			frame: &AudioFrame<'_>,
			http: Client,
			config: RealtimeAsrConfig,
			read_attributes: F,
			upload_slot: &mut Option<RealtimeAsrUpload>,
			last_fixture_sequence: &mut Option<String>,
			realtime_enabled: bool,
			) -> (bool, bool, Option<FinishedSpeechTurn>)
			where
			F: FnOnce() -> std::collections::HashMap<String, String>,
			{
			let was_in_speech = vad.in_speech;
			let turn = vad.observe_frame(
			call_id,
			trace_id,
			participant_alias,
			track_sid_alias,
			frame_count,
			elapsed_ms,
			frame,
			);
			let is_in_speech = vad.in_speech;
			if !was_in_speech && is_in_speech {
			start_realtime_session_for_new_speech(
			http,
			config,
			call_id,
			trace_id,
			vad,
			read_attributes,
			upload_slot,
			last_fixture_sequence,
			realtime_enabled,
			);
			}
			(was_in_speech, is_in_speech, turn)
			}

			fn observe_bound_participant_frame<F>(
			participant_identity: &str,
			expected_participant: Option<&str>,
			vad: &mut SimpleVad,
			call_id: &str,
			trace_id: &str,
			participant_alias: &str,
			track_sid_alias: &str,
			frame_count: u64,
			elapsed_ms: u64,
			frame: &AudioFrame<'_>,
			http: Client,
			config: RealtimeAsrConfig,
			read_attributes: F,
			upload_slot: &mut Option<RealtimeAsrUpload>,
			last_fixture_sequence: &mut Option<String>,
			realtime_enabled: bool,
			) -> (bool, bool, Option<FinishedSpeechTurn>)
			where
			F: FnOnce() -> std::collections::HashMap<String, String>,
			{
			if !is_bound_user_participant(participant_identity, expected_participant) {
			warn!(
			"audioIngressOriginStatus" = "wrong_participant_or_track",
			"runtime helper rejected audio participant before VAD/session"
			);
			return (vad.in_speech, vad.in_speech, None);
			}
			observe_frame_and_start_session(
			vad,
			call_id,
			trace_id,
			participant_alias,
			track_sid_alias,
			frame_count,
			elapsed_ms,
			frame,
			http,
			config,
			read_attributes,
			upload_slot,
			last_fixture_sequence,
			realtime_enabled,
			)
			}

			fn start_realtime_session_for_new_speech(
			http: Client,
			config: RealtimeAsrConfig,
			call_id: &str,
			trace_id: &str,
			vad: &SimpleVad,
			read_attributes: impl FnOnce() -> std::collections::HashMap<String, String>,
			upload_slot: &mut Option<RealtimeAsrUpload>,
			last_fixture_sequence: &mut Option<String>,
			realtime_enabled: bool,
			) {
			let turn_id = format!("turn-{:04}", vad.turn_index);
			let attributes = read_attributes();
			let origin_status = AudioIngressMetadata::origin_status(&attributes);
			let metadata = match AudioIngressMetadata::from_participant(&attributes) {
			Ok(metadata) => metadata,
			Err(reason) => {
			warn!(call_id = %call_id, trace_id = %trace_id, turn_id = %turn_id,
			reason, audioIngressOriginStatus = %AudioIngressMetadata::rejected_origin_status(
			reason, &attributes
			),
			"runtime helper asr_realtime_metadata_rejected");
			return;
			}
			};
			if let Some(metadata) = metadata.as_ref() {
			if !fixture_sequence_is_new(
			last_fixture_sequence.as_deref(),
			&metadata.client_fixture_sequence,
			) {
			warn!(call_id = %call_id, trace_id = %trace_id, turn_id = %turn_id,
			audioIngressOriginStatus = "sequence_replayed_or_regressed",
			"runtime helper asr_realtime_metadata_sequence_rejected");
			return;
			}
			}
			match RealtimeAsrUpload::start(
			http,
			config,
			call_id,
			trace_id,
			&turn_id,
			&vad.speech_samples,
			metadata.as_ref(),
			) {
			Ok(upload) => {
			if let Some(metadata) = metadata {
			*last_fixture_sequence = Some(metadata.client_fixture_sequence);
			}
			info!(call_id = %call_id, trace_id = %trace_id, turn_id = %turn_id,
			origin_status, "runtime helper asr_realtime_session_started");
			*upload_slot = Some(upload);
			}
			Err(error) if realtime_enabled => {
			warn!(call_id = %call_id, trace_id = %trace_id, turn_id = %turn_id,
			error = %safe_error(&error.to_string()),
			"runtime helper asr_realtime_start_failed_fallback");
			}
			Err(_) => {}
			}
			}

			fn fixture_sequence_is_new(previous: Option<&str>, current: &str) -> bool {
			let Some(previous) = previous else {
			return true;
			};
			let current_number = current
			.rsplit_once('-')
			.and_then(\|(_, value)\| value.parse::<u64>().ok());
			let previous_number = previous
			.rsplit_once('-')
			.and_then(\|(_, value)\| value.parse::<u64>().ok());
			match (previous_number, current_number) {
			(Some(previous), Some(current)) => current > previous,
			_ => previous != current,
			}
			}

			struct DrainedUserAudioFrame {
			frame_index: u64,
			captured_elapsed_ms: u64,
			frame: AudioFrame<'static>,
			}

			async fn finish_realtime_asr_upload(
			upload: RealtimeAsrUpload,
			call_id: &str,
			trace_id: &str,
			turn: &FinishedSpeechTurn,
			) -> Option<String> {
			match upload.finish(turn.duration_ms, &turn.end_reason).await {
			Ok(RealtimeAsrOutcome {
			status,
			asr_result_ref,
			provider_alias,
			partial_count,
			fallback_reason,
			fallback_stage,
			chunk_count,
			audio_bytes,
			wall_ms,
			}) => {
			info!(
			call_id = %call_id,
			trace_id = %trace_id,
			turn_id = %turn.turn_id,
			status = %status,
			provider_alias = ?provider_alias,
			partial_count,
			chunk_count,
			audio_bytes,
			wall_ms,
			asr_result_ref_present = asr_result_ref.is_some(),
			fallback_reason = ?fallback_reason,
			fallback_stage = ?fallback_stage,
			"runtime helper asr_realtime_finished"
			);
			if status == "final" {
			asr_result_ref
			} else {
			None
			}
			}
			Err(error) => {
			warn!(
			call_id = %call_id,
			trace_id = %trace_id,
			turn_id = %turn.turn_id,
			error = %safe_error(&error.to_string()),
			"runtime helper asr_realtime_failed_fallback"
			);
			None
			}
			}
			}

			#[derive(Clone)]
			@@ -2258,8 +4184,8 @@
			rms_threshold: f64_env("CV_VAD_RMS_THRESHOLD", 0.012),
			peak_threshold: f64_env("CV_VAD_PEAK_THRESHOLD", 0.08),
			start_frames: u32_env("CV_VAD_START_FRAMES", 5).max(1),
			end_silence_ms: u64_env("CV_VAD_END_SILENCE_MS", 700).max(100),
			min_speech_ms: u64_env("CV_VAD_MIN_SPEECH_MS", 300).max(1),
			end_silence_ms: u64_env("CV_VAD_END_SILENCE_MS", 400).max(100),
			min_speech_ms: u64_env("CV_VAD_MIN_SPEECH_MS", 250).max(1),
			max_turn_ms: u64_env("CV_VAD_MAX_TURN_MS", 10_000).max(1_000),
			initial_ignore_ms: u64_env("CV_VAD_INITIAL_IGNORE_MS", 500),
			}
			@@ -2372,7 +4298,9 @@
			return None;
			}

			let voiced = rms >= self.config.rms_threshold \|\| peak >= self.config.peak_threshold;
			// Align with cb-sdk's energy-based segmentation: peak is diagnostic only,
			// otherwise isolated spikes can keep a turn open until max_turn_ms.
			let voiced = rms >= self.config.rms_threshold;
			if !self.in_speech {
			self.remember_pre_speech_frame(frame);
			}
			@@ -2930,3 +4858,1240 @@
			Ok(())
			}
			}

			#[cfg(test)]
			mod tests {
			use super::*;
			use std::{
			collections::{HashMap, HashSet},
			io::{Read, Write},
			net::TcpListener,
			sync::{
			Arc,
			atomic::{AtomicUsize, Ordering},
			mpsc,
			},
			thread,
			time::Duration,
			};

			#[derive(Debug)]
			enum PreAudioOrderEvent {
			DataReceived {
			sender: String,
			sequence: String,
			},
			TrackSubscribed {
			participant: String,
			attributes: HashMap<String, String>,
			},
			}

			fn drive_pre_audio_order_test_seam(events: &[PreAudioOrderEvent]) -> Vec<&'static str> {
			let mut pending_sequence = None;
			let mut effects = Vec::new();
			for event in events {
			match event {
			PreAudioOrderEvent::DataReceived { sender, sequence } if sender == "user-1" => {
			pending_sequence = Some(sequence.as_str());
			}
			PreAudioOrderEvent::TrackSubscribed {
			participant,
			attributes,
			} => {
			let pending = pending_sequence.is_some();
			let probe_result = pending_sequence.map(\|sequence\| {
			classify_controlled_fixture_attributes(
			participant,
			Some("user-1"),
			attributes,
			sequence,
			)
			.is_ok()
			});
			let mut ack_observed = false;
			let mut observer_started = false;
			start_observer_after_controlled_fixture_probe(pending, probe_result, \|\| {
			if pending && probe_result == Some(true) {
			ack_observed = true;
			}
			observer_started = true;
			});
			if ack_observed {
			effects.push("ack_observed");
			}
			if observer_started {
			effects.push("observer_started");
			}
			pending_sequence = None;
			}
			PreAudioOrderEvent::DataReceived { .. } => {}
			}
			}
			effects
			}

			#[test]
			fn production_vad_session_boundary_reads_updated_attributes() {
			let config = SimpleVadConfig {
			rms_threshold: 0.001,
			peak_threshold: 0.01,
			start_frames: 2,
			end_silence_ms: 100,
			min_speech_ms: 1,
			max_turn_ms: 1_000,
			initial_ignore_ms: 0,
			};
			let mut vad = SimpleVad::new(config);
			let samples = vec![1_000i16; 160];
			let frame = AudioFrame {
			data: samples.as_slice().into(),
			sample_rate: 16_000,
			num_channels: 1,
			samples_per_channel: 160,
			};
			let mut attributes = std::collections::HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			),
			]);
			let mut starts = Vec::new();
			for (session_index, sequence) in [(1, "fixture-01"), (2, "fixture-02")] {
			let was_in_speech = vad.in_speech;
			vad.observe_frame(
			"call-001",
			"trace-001",
			"participant",
			"track",
			session_index * 2 - 1,
			1_000 * session_index,
			&frame,
			);
			vad.observe_frame(
			"call-001",
			"trace-001",
			"participant",
			"track",
			session_index * 2,
			1_000 * session_index + 10,
			&frame,
			);
			let is_in_speech = vad.in_speech;
			assert!(!was_in_speech && is_in_speech);
			attributes.insert("clientFixtureSequence".to_string(), sequence.to_string());
			let metadata = AudioIngressMetadata::from_participant(&attributes)
			.expect("valid participant attributes")
			.expect("controlled fixture metadata");
			let session_line = asr_realtime::session_start_line(
			"call-001",
			"trace-001",
			&format!("turn-{session_index:04}"),
			"nonce-001",
			Some(&metadata),
			)
			.expect("session start line");
			let session_json: serde_json::Value =
			serde_json::from_slice(&session_line).expect("session start json");
			assert_eq!(sequence, session_json["clientFixtureSequence"]);
			starts.push(metadata.client_fixture_sequence);
			vad.reset_current_turn();
			}
			assert_eq!(vec!["fixture-01", "fixture-02"], starts);
			attributes.insert("inputSourceCategory".to_string(), "other".to_string());
			assert!(AudioIngressMetadata::from_participant(&attributes).is_err());
			assert!(
			AudioIngressMetadata::from_participant(&std::collections::HashMap::new())
			.expect("missing attributes is absent")
			.is_none()
			);
			attributes.insert(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			);
			assert!(AudioIngressMetadata::from_participant(&attributes).is_err());
			}

			#[test]
			fn production_observer_rejects_wrong_participant_before_vad_session() {
			assert!(!is_bound_user_participant(
			"participant-other",
			Some("participant-user")
			));
			assert!(is_bound_user_participant(
			"participant-user",
			Some("participant-user")
			));
			assert!(is_bound_user_participant("participant-any", None));
			}

			#[tokio::test]
			async fn production_observer_vad_to_session_entry_reads_each_updated_attribute() {
			let listener = TcpListener::bind("127.0.0.1:0").expect("bind local ASR fixture");
			let address = listener.local_addr().expect("fixture address");
			let (request_tx, request_rx) = mpsc::channel::<String>();
			let captured_count = Arc::new(AtomicUsize::new(0));
			let captured_count_for_server = Arc::clone(&captured_count);
			let server = thread::spawn(move \|\| {
			for _ in 0..2 {
			let (mut stream, _) = listener.accept().expect("accept ASR session");
			stream
			.set_read_timeout(Some(Duration::from_secs(2)))
			.expect("set fixture timeout");
			let mut bytes = Vec::new();
			let mut buffer = [0_u8; 4096];
			loop {
			match stream.read(&mut buffer) {
			Ok(0) => break,
			Ok(size) => {
			bytes.extend_from_slice(&buffer[..size]);
			if bytes.windows(7).any(\|window\| window == b"0\r\n\r\n") {
			break;
			}
			}
			Err(_) => break,
			}
			}
			request_tx
			.send(String::from_utf8_lossy(&bytes).into_owned())
			.expect("capture ASR request");
			captured_count_for_server.fetch_add(1, Ordering::SeqCst);
			stream
			.write_all(b"HTTP/1.1 200 OK\r\ncontent-type: application/json\r\ncontent-length: 39\r\nconnection: close\r\n\r\n{\"code\":0,\"data\":{\"status\":\"ok\"}}")
			.expect("write fixture response");
			}
			});
			let mut vad = SimpleVad::new(SimpleVadConfig {
			rms_threshold: 0.001,
			peak_threshold: 0.01,
			start_frames: 1,
			end_silence_ms: 100,
			min_speech_ms: 1,
			max_turn_ms: 1_000,
			initial_ignore_ms: 0,
			});
			let frame_data = vec![1_000i16; 160];
			let frame = AudioFrame {
			data: frame_data.as_slice().into(),
			sample_rate: 16_000,
			num_channels: 1,
			samples_per_channel: 160,
			};
			let mut attrs = std::collections::HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			),
			]);
			let mut upload = None;
			let mut last_fixture_sequence = None;
			let config = RealtimeAsrConfig {
			enabled: true,
			url: Some(format!("http://{address}/runtime/asr/realtime")),
			runtime_token: Some("test".to_string()),
			runtime_session_nonce: Some("test".to_string()),
			chunk_duration_ms: 200,
			};
			let (was, is, turn) = observe_bound_participant_frame(
			"participant-user",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-user",
			"track-001",
			1,
			1_000,
			&frame,
			Client::new(),
			config.clone(),
			\|\| attrs.clone(),
			&mut upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(!was && is && turn.is_none());
			assert!(upload.is_some());
			upload.take().unwrap().cancel("test").await;
			vad.reset_current_turn();
			attrs.insert(
			"clientFixtureSequence".to_string(),
			"fixture-02".to_string(),
			);
			let (was, is, turn) = observe_bound_participant_frame(
			"participant-user",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-user",
			"track-001",
			2,
			2_000,
			&frame,
			Client::new(),
			config,
			\|\| attrs.clone(),
			&mut upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(!was && is && turn.is_none());
			assert!(upload.is_some());
			upload.take().unwrap().cancel("test").await;

			let first_request = request_rx
			.recv_timeout(Duration::from_secs(2))
			.expect("first session request");
			let second_request = request_rx
			.recv_timeout(Duration::from_secs(2))
			.expect("second session request");
			assert!(first_request.contains("\"clientFixtureSequence\":\"fixture-01\""));
			assert!(second_request.contains("\"clientFixtureSequence\":\"fixture-02\""));
			assert!(
			first_request.contains("\"audioIngressOriginStatus\":\"controlled_fixture_bound\"")
			);
			assert!(
			second_request.contains("\"audioIngressOriginStatus\":\"controlled_fixture_bound\"")
			);
			// The same production boundary rejects a wrong participant before VAD/session creation.
			assert!(!is_bound_user_participant(
			"participant-other",
			Some("participant-user")
			));
			assert_eq!(0, request_rx.try_iter().count());
			vad.reset_current_turn();
			attrs.insert(
			"clientFixtureSequence".to_string(),
			"fixture-03".to_string(),
			);
			let (_, is_wrong, wrong_turn) = observe_bound_participant_frame(
			"participant-other",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-user",
			"track-001",
			3,
			3_000,
			&frame,
			Client::new(),
			RealtimeAsrConfig {
			enabled: true,
			url: Some(format!("http://{address}/runtime/asr/realtime")),
			runtime_token: Some("test".to_string()),
			runtime_session_nonce: Some("test".to_string()),
			chunk_duration_ms: 200,
			},
			\|\| attrs.clone(),
			&mut upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(!is_wrong && wrong_turn.is_none() && upload.is_none());
			vad.reset_current_turn();
			attrs.insert(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			);
			let (_, _, _) = observe_bound_participant_frame(
			"participant-user",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-user",
			"track-001",
			4,
			4_000,
			&frame,
			Client::new(),
			RealtimeAsrConfig {
			enabled: true,
			url: Some(format!("http://{address}/runtime/asr/realtime")),
			runtime_token: Some("test".to_string()),
			runtime_session_nonce: Some("test".to_string()),
			chunk_duration_ms: 200,
			},
			\|\| attrs.clone(),
			&mut upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(upload.is_none());
			vad.reset_current_turn();
			let (_, _, _) = observe_bound_participant_frame(
			"participant-user",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-user",
			"track-001",
			5,
			5_000,
			&frame,
			Client::new(),
			RealtimeAsrConfig {
			enabled: true,
			url: Some(format!("http://{address}/runtime/asr/realtime")),
			runtime_token: Some("test".to_string()),
			runtime_session_nonce: Some("test".to_string()),
			chunk_duration_ms: 200,
			},
			\|\| attrs.clone(),
			&mut upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(upload.is_none());
			vad.reset_current_turn();
			attrs.remove("clientFixtureSequence");
			let (_, _, missing_sequence_turn) = observe_bound_participant_frame(
			"participant-user",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-user",
			"track-001",
			6,
			6_000,
			&frame,
			Client::new(),
			RealtimeAsrConfig {
			enabled: true,
			url: Some(format!("http://{address}/runtime/asr/realtime")),
			runtime_token: Some("test".to_string()),
			runtime_session_nonce: Some("test".to_string()),
			chunk_duration_ms: 200,
			},
			\|\| attrs.clone(),
			&mut upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(missing_sequence_turn.is_none() && upload.is_none());
			assert_eq!(
			"sequence_absent",
			AudioIngressMetadata::rejected_origin_status("incomplete_metadata", &attrs)
			);
			assert_eq!(2, captured_count.load(Ordering::SeqCst));
			vad.reset_current_turn();
			attrs.insert("inputSourceCategory".to_string(), "other".to_string());
			let mut invalid_upload = None;
			let (_, _, invalid_turn) = observe_bound_participant_frame(
			"participant-user",
			Some("participant-user"),
			&mut vad,
			"call-001",
			"trace-001",
			"participant-other",
			"track-001",
			3,
			3_000,
			&frame,
			Client::new(),
			RealtimeAsrConfig {
			enabled: true,
			url: Some("http://127.0.0.1:9".to_string()),
			runtime_token: Some("test".to_string()),
			runtime_session_nonce: Some("test".to_string()),
			chunk_duration_ms: 200,
			},
			\|\| attrs,
			&mut invalid_upload,
			&mut last_fixture_sequence,
			true,
			);
			assert!(invalid_turn.is_none());
			assert!(invalid_upload.is_none());
			assert_eq!(2, captured_count.load(Ordering::SeqCst));
			assert_eq!(0, request_rx.try_iter().count());
			server.join().expect("fixture server");
			}

			#[test]
			fn reply_chunk_marker_state_emits_turn_first_once_and_later_segment_first_once() {
			let mut state = ReplyChunkMarkerState::default();

			assert_eq!(ReplyChunkMarker::FirstReply, state.observe(Some(1)));
			assert_eq!(ReplyChunkMarker::None, state.observe(Some(1)));
			assert_eq!(ReplyChunkMarker::SegmentFirst, state.observe(Some(2)));
			assert_eq!(ReplyChunkMarker::None, state.observe(Some(2)));
			assert_eq!(ReplyChunkMarker::SegmentFirst, state.observe(Some(3)));
			}

			#[test]
			fn reply_chunk_marker_state_without_segment_only_emits_turn_first() {
			let mut state = ReplyChunkMarkerState::default();

			assert_eq!(ReplyChunkMarker::FirstReply, state.observe(None));
			assert_eq!(ReplyChunkMarker::None, state.observe(None));
			}

			#[test]
			fn runtime_turn_stream_audio_chunk_reads_segment_seq() {
			let event: RuntimeTurnStreamEvent = serde_json::from_str(
			r#"{"type":"reply_audio_chunk","audioChunk":{"chunkSeq":4,"segmentSeq":2,"format":"pcm_s16le","payloadBase64":"AA==","last":false}}"#,
			)
			.expect("turn stream event");

			assert_eq!(
			Some(2),
			event.audio_chunk.and_then(\|chunk\| chunk.segment_seq)
			);
			}

			#[test]
			fn runtime_turn_stream_reads_frozen_m5_and_audio_chunk_timing_contract() {
			let activity: RuntimeTurnStreamEvent = serde_json::from_str(
			r#"{"type":"activity","callId":"call-1","traceId":"trace-1","turnId":"turn-1","activity":{"eventType":"tts_first_audio_chunk_ready","extension":{"streamTimingVersion":1,"streamAnchorId":"0123456789abcdef","streamAnchorServerDeltaMs":1200,"runtimeSessionNonceHash":"abcdef012345","segmentSeq":1,"streamTimingValidation":"bound"}}}"#,
			)
			.expect("m5 activity event");
			let audio: RuntimeTurnStreamEvent = serde_json::from_str(
			r#"{"type":"reply_audio_chunk","callId":"call-1","traceId":"trace-1","turnId":"turn-1","audioChunk":{"chunkSeq":1,"segmentSeq":1,"streamTimingVersion":1,"streamAnchorId":"0123456789abcdef","format":"pcm_s16le","payloadBase64":"AA==","last":false}}"#,
			)
			.expect("timed audio chunk event");

			assert_eq!(Some("call-1"), activity.call_id.as_deref());
			assert_eq!(Some("trace-1"), activity.trace_id.as_deref());
			assert_eq!(Some("turn-1"), activity.turn_id.as_deref());
			let extension = activity.activity.unwrap().extension.unwrap();
			assert_eq!(Some(1), extension.stream_timing_version);
			assert_eq!(Some(1200), extension.stream_anchor_server_delta_ms);
			assert_eq!(
			Some("0123456789abcdef"),
			audio.audio_chunk.unwrap().stream_anchor_id.as_deref()
			);
			}

			#[test]
			fn runtime_turn_stream_timing_records_m6_and_m7_once_then_rejects_terminal_late_events() {
			let nonce = "runtime-nonce";
			let nonce_hash = runtime_session_nonce_hash(nonce);
			let activity: RuntimeTurnStreamEvent = serde_json::from_str(&format!(
			r#"{{"type":"activity","callId":"call-1","traceId":"trace-1","turnId":"turn-1","activity":{{"eventType":"tts_first_audio_chunk_ready","extension":{{"streamTimingVersion":1,"streamAnchorId":"0123456789abcdef","streamAnchorServerDeltaMs":1200,"runtimeSessionNonceHash":"{nonce_hash}","segmentSeq":1,"streamTimingValidation":"bound"}}}}}}"#,
			))
			.expect("m5 activity event");
			let audio: RuntimeTurnStreamEvent = serde_json::from_str(
			r#"{"type":"reply_audio_chunk","callId":"call-1","traceId":"trace-1","turnId":"turn-1","audioChunk":{"chunkSeq":1,"segmentSeq":1,"streamTimingVersion":1,"streamAnchorId":"0123456789abcdef","format":"pcm_s16le","payloadBase64":"AA==","last":false}}"#,
			)
			.expect("timed audio chunk event");
			let mut state = RuntimeTurnStreamState::default();

			assert!(state.arm_timing_anchor("call-1", "trace-1", "turn-1", nonce, &activity));
			let chunk = audio.audio_chunk.as_ref().expect("audio chunk");
			assert!(
			state
			.record_m6("call-1", "trace-1", "turn-1", &audio, chunk)
			.is_some()
			);
			assert!(
			state
			.record_m6("call-1", "trace-1", "turn-1", &audio, chunk)
			.is_none()
			);
			assert!(state.record_m7().is_some());
			assert!(state.record_m7().is_none());

			state.close_timing();
			assert_eq!(RuntimeTurnStreamTimingPhase::Closed, state.timing.phase);
			assert!(state.timing.anchor.is_none());
			assert!(!state.arm_timing_anchor("call-1", "trace-1", "turn-1", nonce, &activity));
			assert!(
			state
			.record_m6("call-1", "trace-1", "turn-1", &audio, chunk)
			.is_none()
			);
			assert!(state.record_m7().is_none());
			}

			#[test]
			fn device_output_contract_is_reliable_and_deduplicated() {
			let output = RuntimeTurnDeviceOutput {
			command_id: Some("cmd-1".to_string()),
			command_code: Some("custom.app.DeviceLevelChange".to_string()),
			params: Some(serde_json::json!({"level": 1})),
			};
			let mut published = HashSet::new();
			assert!(should_publish_device_output(&mut published, &output));
			assert!(!should_publish_device_output(&mut published, &output));
			assert_eq!(published.len(), 1);
			}

			#[test]
			fn device_output_invalid_or_missing_command_is_fail_closed() {
			for output in [
			RuntimeTurnDeviceOutput {
			command_id: None,
			command_code: Some("custom.app.DeviceLevelChange".to_string()),
			params: None,
			},
			RuntimeTurnDeviceOutput {
			command_id: Some("cmd-1".to_string()),
			command_code: None,
			params: None,
			},
			] {
			let mut published = HashSet::new();
			assert!(!should_publish_device_output(&mut published, &output));
			assert!(published.is_empty());
			}
			}

			#[test]
			fn controlled_fixture_probe_requires_bound_hashes_and_protocol() {
			let call_id = "call-ack-1";
			let trace_id = "trace-ack-1";
			let payload = serde_json::to_vec(&json!({
			"type": CONTROLLED_FIXTURE_PROBE_TOPIC,
			"protocolVersion": CONTROLLED_FIXTURE_PROTOCOL_VERSION,
			"callIdHash": sha256_hex(call_id),
			"callTraceIdHash": sha256_hex(trace_id),
			"generation": CONTROLLED_FIXTURE_GENERATION,
			"clientFixtureSequence": "fixture-01"
			}))
			.unwrap();
			let sender = ParticipantIdentity("user-1".to_string());
			let pending =
			controlled_fixture_probe(&payload, call_id, trace_id, &sender, Some("user-1"))
			.expect("valid probe");
			assert_eq!(pending.sequence, "fixture-01");
			assert_eq!(pending.call_id_hash, sha256_hex(call_id));
			assert_eq!(pending.call_trace_id_hash, sha256_hex(trace_id));
			assert_eq!(pending.generation, CONTROLLED_FIXTURE_GENERATION);
			assert!(
			controlled_fixture_probe(&payload, call_id, "other-trace", &sender, Some("user-1"),)
			.is_none()
			);
			assert!(
			controlled_fixture_probe(
			&payload,
			call_id,
			trace_id,
			&ParticipantIdentity("other-user".to_string()),
			Some("user-1"),
			)
			.is_none()
			);
			}

			#[test]
			fn controlled_fixture_attributes_ack_only_on_exact_current_sequence() {
			let mut attributes = std::collections::HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			),
			]);
			assert!(
			classify_controlled_fixture_attributes(
			"user-1",
			Some("user-1"),
			&attributes,
			"fixture-01"
			)
			.is_ok()
			);
			attributes.insert(
			"clientFixtureSequence".to_string(),
			"fixture-02".to_string(),
			);
			assert_eq!(
			classify_controlled_fixture_attributes(
			"user-1",
			Some("user-1"),
			&attributes,
			"fixture-01"
			),
			Err("wrong_sequence")
			);
			attributes.remove("clientFixtureSequence");
			assert_eq!(
			classify_controlled_fixture_attributes(
			"user-1",
			Some("user-1"),
			&attributes,
			"fixture-01"
			),
			Err("missing_sequence")
			);
			assert_eq!(
			classify_controlled_fixture_attributes(
			"other-user",
			Some("user-1"),
			&attributes,
			"fixture-01"
			),
			Err("wrong_participant")
			);
			}

			#[test]
			fn controlled_fixture_probe_runtime_projection_binds_request_hashes_and_audio_gate() {
			let call_id = "private-call-value";
			let trace_id = "private-trace-value";
			let sequence = "private-sequence-value";
			let call_id_hash = sha256_hex(call_id);
			let trace_id_hash = sha256_hex(trace_id);
			let mut observer_starts = 0;
			let (ack_result, reject_reason, observed) =
			controlled_fixture_ack_classification(Err("wrong_source"));
			let stages = [
			("data_received", None, None),
			("attributes_classified", Some(ack_result), reject_reason),
			("ack_publish_started", Some(ack_result), reject_reason),
			("ack_publish_completed", Some(ack_result), reject_reason),
			("audio_observer_blocked", Some(ack_result), reject_reason),
			];
			for (stage, result, reason) in stages {
			let event = controlled_fixture_probe_event(
			call_id,
			trace_id,
			stage,
			&call_id_hash,
			&trace_id_hash,
			CONTROLLED_FIXTURE_GENERATION,
			sequence,
			observed,
			result,
			reason,
			);
			assert_eq!(event["type"], "cv_activity");
			assert_eq!(event["eventName"], "controlled_fixture_attribute_probe");
			assert_eq!(event["extension"]["call_id_hash"], call_id_hash);
			assert_eq!(event["extension"]["trace_id_hash"], trace_id_hash);
			assert_eq!(event["extension"]["stage"], stage);
			let output = event.to_string();
			assert!(!output.contains(sequence));
			}
			assert!(!start_observer_after_controlled_fixture_probe(
			true,
			Some(observed),
			\|\| observer_starts += 1,
			));
			assert_eq!(observer_starts, 0);

			let (ack_result, reject_reason, observed) = controlled_fixture_ack_classification(Ok(()));
			let allowed = controlled_fixture_probe_event(
			call_id,
			trace_id,
			"audio_observer_allowed",
			&call_id_hash,
			&trace_id_hash,
			CONTROLLED_FIXTURE_GENERATION,
			sequence,
			observed,
			Some(ack_result),
			reject_reason,
			);
			assert_eq!(allowed["extension"]["trace_id_hash"], trace_id_hash);
			assert!(start_observer_after_controlled_fixture_probe(
			true,
			Some(observed),
			\|\| observer_starts += 1,
			));
			assert_eq!(observer_starts, 1);
			}

			#[test]
			fn controlled_fixture_probe_observed_and_failure_enums_are_stable() {
			assert_eq!(
			controlled_fixture_ack_classification(Ok(())),
			("observed", None, true)
			);
			assert_eq!(
			controlled_fixture_ack_classification(Err("timeout")),
			("timeout", Some("expired"), false)
			);
			for reason in [
			"missing_attributes",
			"wrong_source",
			"missing_sequence",
			"wrong_sequence",
			"wrong_participant",
			] {
			assert_eq!(
			controlled_fixture_ack_classification(Err(reason)),
			("rejected", Some(reason), false)
			);
			}
			assert_eq!(
			controlled_fixture_ack_classification(Err("unclassified")),
			("rejected", Some("unknown"), false)
			);
			}

			#[test]
			fn production_probe_binding_drives_rejected_and_observed_ack_without_local_rehash() {
			let request_call_hash = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
			let request_trace_hash = "bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb";
			let probe = PendingControlledFixtureProbe {
			sender: ParticipantIdentity("user-1".to_string()),
			call_id_hash: request_call_hash.to_string(),
			call_trace_id_hash: request_trace_hash.to_string(),
			generation: CONTROLLED_FIXTURE_GENERATION,
			sequence: "fixture-01".to_string(),
			received_at: Instant::now(),
			expires_at: Instant::now() + CONTROLLED_FIXTURE_PROBE_TTL,
			};

			let (ack_result, reject_reason, observed) =
			controlled_fixture_ack_classification(Err("wrong_sequence"));
			let rejected_ack = controlled_fixture_ack_from_probe(&probe, observed, reject_reason);
			let rejected_json = serde_json::to_value(&rejected_ack).unwrap();
			let mut rejected_observer_starts = 0;
			assert_eq!(ack_result, "rejected");
			assert_eq!(rejected_json["callIdHash"], request_call_hash);
			assert_eq!(rejected_json["callTraceIdHash"], request_trace_hash);
			assert_eq!(rejected_json["rejectReason"], "wrong_sequence");
			assert!(!start_observer_after_controlled_fixture_probe(
			true,
			Some(observed),
			\|\| rejected_observer_starts += 1,
			));
			assert_eq!(rejected_observer_starts, 0);

			let (ack_result, reject_reason, observed) = controlled_fixture_ack_classification(Ok(()));
			let observed_ack = controlled_fixture_ack_from_probe(&probe, observed, reject_reason);
			let observed_json = serde_json::to_value(&observed_ack).unwrap();
			let mut observed_observer_starts = 0;
			assert_eq!(ack_result, "observed");
			assert_eq!(observed_json["callIdHash"], request_call_hash);
			assert_eq!(observed_json["callTraceIdHash"], request_trace_hash);
			assert!(observed_json.get("rejectReason").is_none());
			assert!(start_observer_after_controlled_fixture_probe(
			true,
			Some(observed),
			\|\| observed_observer_starts += 1,
			));
			assert_eq!(observed_observer_starts, 1);
			}

			#[tokio::test]
			async fn production_ack_publish_failure_keeps_observer_session_and_audio_closed() {
			let mut acknowledged = HashSet::new();
			let probe_result = complete_controlled_fixture_ack_publish(
			async { Err::<(), ()>(()) },
			"runtime-call-publish-failure",
			"runtime-trace-publish-failure",
			true,
			"observed",
			None,
			"call-publish-failure",
			"trace-publish-failure",
			CONTROLLED_FIXTURE_GENERATION,
			"fixture-01",
			&mut acknowledged,
			)
			.await;
			let mut observer_starts = 0;
			let mut session_starts = 0;
			let mut audio_starts = 0;
			let mut speaking_starts = 0;
			assert!(!start_observer_after_controlled_fixture_probe(
			true,
			Some(probe_result.observed),
			\|\| {
			observer_starts += 1;
			session_starts += 1;
			audio_starts += 1;
			speaking_starts += 1;
			},
			));
			assert_eq!(
			probe_result,
			ControlledFixtureAckPublishOutcome {
			observed: false,
			published: false,
			}
			);
			assert!(acknowledged.is_empty());
			assert_eq!(observer_starts, 0);
			assert_eq!(session_starts, 0);
			assert_eq!(audio_starts, 0);
			assert_eq!(speaking_starts, 0);

			let observed_result = complete_controlled_fixture_ack_publish(
			async { Ok::<(), ()>(()) },
			"runtime-call-publish-success",
			"runtime-trace-publish-success",
			true,
			"observed",
			None,
			"call-publish-success",
			"trace-publish-success",
			CONTROLLED_FIXTURE_GENERATION,
			"fixture-02",
			&mut acknowledged,
			)
			.await;
			let mut successful_observer_starts = 0;
			assert!(start_observer_after_controlled_fixture_probe(
			true,
			Some(observed_result.observed),
			\|\| successful_observer_starts += 1,
			));
			assert_eq!(
			observed_result,
			ControlledFixtureAckPublishOutcome {
			observed: true,
			published: true,
			}
			);
			assert!(acknowledged.contains("fixture-02"));
			assert_eq!(successful_observer_starts, 1);
			}

			#[tokio::test]
			async fn production_attribute_observation_accepts_server_visibility_within_probe_ttl() {
			let expected = HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			),
			]);
			let mut reads = 0;
			let result = observe_controlled_fixture_attributes(
			Instant::now() + CONTROLLED_FIXTURE_PROBE_TTL,
			"user-1",
			Some("user-1"),
			"fixture-01",
			\|\| {
			reads += 1;
			if reads <= 3 {
			HashMap::new()
			} else {
			expected.clone()
			}
			},
			)
			.await;
			assert_eq!(result, Ok(()));
			assert_eq!(reads, 4);
			}

			#[tokio::test]
			async fn production_attribute_observation_rejects_wrong_sequence_without_audio_effect() {
			let attributes = HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-02".to_string(),
			),
			]);
			let result = observe_controlled_fixture_attributes(
			Instant::now() + CONTROLLED_FIXTURE_PROBE_TTL,
			"user-1",
			Some("user-1"),
			"fixture-01",
			\|\| attributes.clone(),
			)
			.await;
			let mut observer_starts = 0;
			assert_eq!(result, Err("wrong_sequence"));
			assert!(!start_observer_after_controlled_fixture_probe(
			true,
			Some(result.is_ok()),
			\|\| observer_starts += 1,
			));
			assert_eq!(observer_starts, 0);
			}

			#[tokio::test]
			async fn production_post_expiry_observation_records_bounded_visibility_without_second_ack() {
			let started_at = Instant::now();
			let active = Arc::new(AtomicBool::new(true));
			let expected = HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			),
			]);
			let mut acknowledged = HashSet::new();
			let expired_ack = complete_controlled_fixture_ack_publish(
			async { Ok::<(), ()>(()) },
			"runtime-call-post-expiry",
			"runtime-trace-post-expiry",
			false,
			"timeout",
			Some("expired"),
			"call-post-expiry",
			"trace-post-expiry",
			CONTROLLED_FIXTURE_GENERATION,
			"fixture-01",
			&mut acknowledged,
			)
			.await;
			assert_eq!(
			expired_ack,
			ControlledFixtureAckPublishOutcome {
			observed: false,
			published: true,
			}
			);
			let evidence = observe_controlled_fixture_post_expiry(
			started_at,
			started_at + CONTROLLED_FIXTURE_POST_EXPIRY_WINDOW,
			"user-1",
			Some("user-1"),
			"fixture-01",
			active,
			\|\| {
			if started_at.elapsed() >= Duration::from_millis(300) {
			expected.clone()
			} else {
			HashMap::new()
			}
			},
			)
			.await;
			assert_eq!(acknowledged.len(), 1);
			assert_eq!(
			evidence,
			Some(ControlledFixtureVisibilityEvidence {
			first_visible_bucket: "250_500ms",
			visibility_source: "participant_attributes_poll",
			binding_matched: true,
			})
			);

			let never_started_at = Instant::now();
			assert_eq!(
			observe_controlled_fixture_post_expiry(
			never_started_at,
			never_started_at + Duration::from_millis(40),
			"user-1",
			Some("user-1"),
			"fixture-01",
			Arc::new(AtomicBool::new(true)),
			HashMap::new,
			)
			.await,
			Some(ControlledFixtureVisibilityEvidence {
			first_visible_bucket: "never_visible_within_observation_window",
			visibility_source: "participant_attributes_poll",
			binding_matched: true,
			})
			);

			assert_eq!(
			observe_controlled_fixture_post_expiry(
			Instant::now(),
			Instant::now() + Duration::from_millis(50),
			"cross-call-user",
			Some("user-1"),
			"fixture-01",
			Arc::new(AtomicBool::new(true)),
			\|\| expected.clone(),
			)
			.await,
			None
			);

			let inactive = Arc::new(AtomicBool::new(false));
			assert_eq!(
			observe_controlled_fixture_post_expiry(
			Instant::now(),
			Instant::now() + Duration::from_millis(50),
			"user-1",
			Some("user-1"),
			"fixture-01",
			inactive,
			HashMap::new,
			)
			.await,
			None
			);
			assert_eq!(acknowledged.len(), 1);

			let probe = PendingControlledFixtureProbe {
			sender: ParticipantIdentity("user-1".to_string()),
			call_id_hash: "call-post-expiry".to_string(),
			call_trace_id_hash: "trace-post-expiry".to_string(),
			generation: CONTROLLED_FIXTURE_GENERATION,
			sequence: "fixture-01".to_string(),
			received_at: started_at,
			expires_at: started_at + CONTROLLED_FIXTURE_PROBE_TTL,
			};
			let event = controlled_fixture_visibility_event(
			"runtime-call-post-expiry",
			"runtime-trace-post-expiry",
			&probe,
			&evidence.unwrap(),
			);
			let extension = event["extension"].as_object().unwrap();
			let mut keys = extension.keys().map(String::as_str).collect::<Vec<_>>();
			keys.sort_unstable();
			assert_eq!(
			keys,
			vec![
			"binding_matched",
			"call_id_hash",
			"evidence_count",
			"first_visible_bucket",
			"generation",
			"sequence_hash",
			"stage",
			"trace_id_hash",
			"visibility_source",
			]
			);
			let encoded = event.to_string();
			for forbidden in [
			"\"participant\":",
			"\"room\":",
			"\"track\":",
			"\"payload\":",
			"\"audio\":",
			] {
			assert!(!encoded.contains(forbidden));
			}
			}

			#[test]
			fn controlled_fixture_ack_payload_is_reliable_and_redacted() {
			let ack = ControlledFixtureAttributeAck {
			message_type: CONTROLLED_FIXTURE_ACK_TOPIC,
			protocol_version: CONTROLLED_FIXTURE_PROTOCOL_VERSION,
			call_id_hash: sha256_hex("call-1"),
			call_trace_id_hash: sha256_hex("trace-1"),
			generation: CONTROLLED_FIXTURE_GENERATION,
			client_fixture_sequence: "fixture-01".to_string(),
			result: "observed",
			input_source_category: Some("controlled_fixture"),
			reject_reason: None,
			};
			let encoded = serde_json::to_vec(&ack).unwrap();
			let decoded: serde_json::Value = serde_json::from_slice(&encoded).unwrap();
			assert_eq!(decoded["type"], CONTROLLED_FIXTURE_ACK_TOPIC);
			assert_eq!(
			decoded["protocolVersion"],
			CONTROLLED_FIXTURE_PROTOCOL_VERSION
			);
			assert_eq!(decoded["result"], "observed");
			assert!(decoded.get("callId").is_none());
			assert!(decoded.get("traceId").is_none());
			assert!(decoded.get("participantIdentity").is_none());
			assert!(decoded.get("audio").is_none());
			}

			#[test]
			fn controlled_fixture_probe_does_not_create_session_or_audio_side_effects() {
			let attributes = std::collections::HashMap::new();
			assert_eq!(
			classify_controlled_fixture_attributes(
			"user-1",
			Some("user-1"),
			&attributes,
			"fixture-01"
			),
			Err("missing_attributes")
			);
			assert_eq!(
			CONTROLLED_FIXTURE_PROBE_TOPIC,
			"controlled_fixture_attribute_probe"
			);
			assert_eq!(
			CONTROLLED_FIXTURE_ACK_TOPIC,
			"controlled_fixture_attribute_ack"
			);
			}

			#[test]
			fn controlled_fixture_probe_must_be_observed_before_audio_observer() {
			assert!(controlled_fixture_observer_gate(false, None));
			assert!(controlled_fixture_observer_gate(true, Some(true)));
			assert!(!controlled_fixture_observer_gate(true, Some(false)));
			assert!(!controlled_fixture_observer_gate(true, None));
			}

			#[test]
			fn production_event_order_probe_then_track_publishes_ack_before_observer() {
			let attributes = HashMap::from([
			(
			"inputSourceCategory".to_string(),
			"controlled_fixture".to_string(),
			),
			(
			"clientFixtureSequence".to_string(),
			"fixture-01".to_string(),
			),
			]);
			let effects = drive_pre_audio_order_test_seam(&[
			PreAudioOrderEvent::DataReceived {
			sender: "user-1".to_string(),
			sequence: "fixture-01".to_string(),
			},
			PreAudioOrderEvent::TrackSubscribed {
			participant: "user-1".to_string(),
			attributes,
			},
			]);
			assert_eq!(effects, ["ack_observed", "observer_started"]);
			}

			#[test]
			fn production_event_order_negative_probe_has_no_observer_or_session_effect() {
			let mut invalid = HashMap::new();
			invalid.insert(
			"inputSourceCategory".to_string(),
			"ordinary_mic".to_string(),
			);
			let effects = drive_pre_audio_order_test_seam(&[
			PreAudioOrderEvent::DataReceived {
			sender: "user-1".to_string(),
			sequence: "fixture-01".to_string(),
			},
			PreAudioOrderEvent::TrackSubscribed {
			participant: "user-1".to_string(),
			attributes: invalid,
			},
			]);
			assert!(effects.is_empty());
			}

			#[test]
			fn production_audio_branch_orders_probe_before_spawn_callsite() {
			let source = include_str!("main.rs");
			let branch = source
			.find("RoomEvent::TrackSubscribed {\n track: RemoteTrack::Audio")
			.expect("audio TrackSubscribed production branch");
			let branch_source = &source[branch..];
			let probe = branch_source
			.find("let probe_result = process_controlled_fixture_probe")
			.expect("probe must be processed in audio branch");
			let spawn = branch_source
			.find("start_observer_after_controlled_fixture_probe")
			.expect("spawn must use shared order entry");
			assert!(
			probe < spawn,
			"probe must precede shared observer spawn entry"
			);
			}
			}