chore: bind final observer test candidate

cai

2026-08-08 c5bfc24db1ae38d8488e566a2c9ff8afd42c0e5c

 src/main.rs

@@ -1,7 +1,10 @@
mod asr_realtime;
mod audio;
mod service;

use std::{
    borrow::Cow,
    collections::HashSet,
    env, fs,
    path::{Path, PathBuf},
    sync::{
@@ -12,6 +15,9 @@
};

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 +30,35 @@
    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";

#[tokio::main(flavor = "multi_thread")]
async fn main() -> Result<()> {
@@ -270,6 +288,11 @@
    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 +355,11 @@
    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 +371,11 @@
            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 +407,32 @@
                .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 +454,14 @@
            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 +663,36 @@
        "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 +709,7 @@
    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 +731,14 @@
            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 +751,7 @@
    turn_bridge_config: TurnBridgeConfig,
    http: Client,
    sink: Arc<BotAudioOutputSink>,
    user_participant_identity: Option<String>,
) {
    info!(
        call_id = %call_id,
@@ -675,6 +775,15 @@
                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();
@@ -700,6 +809,7 @@
                    turn_bridge_config.clone(),
                    http.clone(),
                    sink.clone(),
                    participant,
                );
            }
            RoomEvent::TrackSubscribed {
@@ -750,6 +860,7 @@
    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 +917,13 @@
                    "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 +934,7 @@
                    &turn,
                    &path_ref,
                    byte_size,
                    asr_result_ref.as_deref(),
                    turn_pipeline_started_at,
                )
                .await
@@ -882,12 +998,17 @@
                &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 +1124,251 @@
    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 +1378,7 @@
    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 +1386,7 @@
        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 +1394,8 @@
            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 +1474,7 @@
            .await?;
        }
    }
    state.close_timing();
    if !state.completed {
        warn!(
            call_id = %call_id,
@@ -1235,6 +1604,7 @@
                call_id,
                trace_id,
                turn,
                &event,
                audio_chunk,
                state,
                turn_pipeline_started_at,
@@ -1246,6 +1616,9 @@
        }
        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 +1626,7 @@
        }
        Some("turn_completed") => {
            state.completed = true;
            state.close_timing();
            info!(
                call_id = %call_id,
                trace_id = %trace_id,
@@ -1263,6 +1637,7 @@
            );
        }
        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 +1672,7 @@
        }
        Some("turn_cancelled") => {
            state.completed = true;
            state.close_timing();
            info!(
                call_id = %call_id,
                trace_id = %trace_id,
@@ -1329,6 +1705,19 @@
        }
        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 +1776,7 @@
    call_id: &str,
    trace_id: &str,
    turn: &FinishedSpeechTurn,
    event: &RuntimeTurnStreamEvent,
    audio_chunk: &RuntimeTurnStreamAudioChunk,
    state: &mut RuntimeTurnStreamState,
    turn_pipeline_started_at: Instant,
@@ -1406,6 +1796,58 @@
        .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 +1939,7 @@
            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 +1967,33 @@
        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 +2074,7 @@
    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 +2082,7 @@
        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 +2090,8 @@
            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 +2382,10 @@
    #[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 +2413,20 @@
    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 +2447,12 @@
    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 +2465,266 @@
            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 +2744,12 @@
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 +2785,12 @@
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 +2807,23 @@
    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 +2856,30 @@
    #[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 +2921,7 @@
    turn_bridge_config: TurnBridgeConfig,
    http: Client,
    sink: Arc<BotAudioOutputSink>,
    participant: RemoteParticipant,
) -> JoinHandle<()> {
    tokio::spawn(async move {
        let mut stream = NativeAudioStream::new(
@@ -2144,6 +2930,68 @@
            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 +2999,14 @@
        } 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 +3034,8 @@

            if let Some(vad) = simple_vad.as_mut() {
                if vad_enabled_gate.load(Ordering::Acquire) {
                    if let Some(turn) = vad.observe_frame(
                    let (was_in_speech, is_in_speech, turn) = observe_frame_and_start_session(
                        vad,
                        &call_id,
                        &trace_id,
                        &participant_alias,
@@ -2191,7 +3043,40 @@
                        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 +3084,22 @@
                            &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 +3120,41 @@
                &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 +3168,182 @@
            "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 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 metadata = match AudioIngressMetadata::from_participant(&read_attributes()) {
        Ok(metadata) => metadata,
        Err(reason) => {
            warn!(call_id = %call_id, trace_id = %trace_id, turn_id = %turn_id,
                reason, "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,
                "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,
                "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)]
@@ -2932,3 +4037,460 @@
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::{
        ReplyChunkMarker, ReplyChunkMarkerState, RuntimeTurnDeviceOutput, RuntimeTurnStreamEvent,
        RuntimeTurnStreamState, RuntimeTurnStreamTimingPhase, runtime_session_nonce_hash,
        should_publish_device_output,
    };
    use std::{
        collections::HashSet,
        io::{Read, Write},
        net::TcpListener,
        sync::mpsc,
        thread,
        time::Duration,
    };

    #[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 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");
                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_frame_and_start_session(
            &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_frame_and_start_session(
            &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\\\""));
        server.join().expect("fixture server");

        // 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-01".to_string(),
        );
        let (_, _, _) = observe_frame_and_start_session(
            &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!(upload.is_none());
        vad.reset_current_turn();
        attrs.insert(
            "clientFixtureSequence".to_string(),
            "fixture-00".to_string(),
        );
        let (_, _, _) = observe_frame_and_start_session(
            &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();
        attrs.insert("inputSourceCategory".to_string(), "other".to_string());
        let mut invalid_upload = None;
        let (_, _, invalid_turn) = observe_frame_and_start_session(
            &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());
    }

    #[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());
        }
    }
}