feat(helper): distinguish current participant visibility

cai

2026-08-12 4c14ddfeb8964d09b83f14ce7629e42863fa67ce

 src/main.rs

@@ -6,6 +6,7 @@
    borrow::Cow,
    collections::HashSet,
    env, fs,
    future::Future,
    path::{Path, PathBuf},
    sync::{
        Arc,
@@ -63,9 +64,24 @@
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_RECHECKS: usize = 3;
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")]
@@ -96,11 +112,29 @@
    reject_reason: Option<&'static str>,
}

#[derive(Debug)]
#[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,
    visibility_result: &'static str,
    binding_matched: bool,
}

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

fn sha256_hex(value: &str) -> String {
@@ -111,6 +145,184 @@
        .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(
@@ -133,11 +345,174 @@
    {
        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,
        expires_at: Instant::now() + CONTROLLED_FIXTURE_PROBE_TTL,
        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_views<F, G>(
    received_at: Instant,
    observation_deadline: Instant,
    held_participant: &str,
    expected_participant: Option<&str>,
    requested_sequence: &str,
    lifecycle_active: Arc<AtomicBool>,
    mut read_held_attributes: F,
    mut read_current_participant: G,
) -> Option<ControlledFixtureVisibilityEvidence>
where
    F: FnMut() -> std::collections::HashMap<String, String>,
    G: FnMut() -> Option<(String, std::collections::HashMap<String, String>)>,
{
    loop {
        if !lifecycle_active.load(Ordering::Acquire) {
            return None;
        }
        let now = Instant::now();
        let held_decision = classify_controlled_fixture_attributes(
            held_participant,
            expected_participant,
            &read_held_attributes(),
            requested_sequence,
        );
        match held_decision {
            Ok(()) => {
                return Some(ControlledFixtureVisibilityEvidence {
                    first_visible_bucket: controlled_fixture_visibility_bucket(
                        now.saturating_duration_since(received_at),
                    ),
                    visibility_source: "participant_attributes_poll",
                    visibility_result: "held_visible",
                    binding_matched: true,
                });
            }
            Err("missing_attributes") => {}
            Err(_) => return None,
        }
        let Some((current_identity, current_attributes)) = read_current_participant() else {
            return None;
        };
        match classify_controlled_fixture_attributes(
            &current_identity,
            expected_participant,
            &current_attributes,
            requested_sequence,
        ) {
            Ok(()) => {
                return Some(ControlledFixtureVisibilityEvidence {
                    first_visible_bucket: controlled_fixture_visibility_bucket(
                        now.saturating_duration_since(received_at),
                    ),
                    visibility_source: "current_room_lookup",
                    visibility_result: "held_stale_current_visible",
                    binding_matched: true,
                });
            }
            Err("missing_attributes") => {}
            Err(_) => return None,
        }
        if now >= observation_deadline {
            return Some(ControlledFixtureVisibilityEvidence {
                first_visible_bucket: "never_visible_within_observation_window",
                visibility_source: "held_and_current_room_lookup",
                visibility_result: "unavailable_both",
                binding_matched: true,
            });
        }
        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,
            "visibility_result": evidence.visibility_result,
            "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,
    room: Arc<Room>,
    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_views(
            probe.received_at,
            probe.received_at + CONTROLLED_FIXTURE_POST_EXPIRY_WINDOW,
            &participant_identity,
            expected_participant.as_deref(),
            &probe.sequence,
            lifecycle_active.clone(),
            || participant.attributes(),
            || {
                room.remote_participants()
                    .get(&probe.sender)
                    .map(|current| (current.identity().to_string(), current.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(
@@ -171,6 +546,59 @@
        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")]
@@ -884,6 +1312,7 @@
    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 {
@@ -914,33 +1343,72 @@
                    track_source = %track_source,
                    "runtime helper user_track_subscribed"
                );
                let pending_binding = pending_probe.clone();
                let participant_for_probe = participant.clone();
                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,
                );
                current_user_participant = Some(participant_for_probe);
                process_controlled_fixture_probe(
                let probe_result = process_controlled_fixture_probe(
                    &mut pending_probe,
                    &mut acknowledged_probe_sequences,
                    current_user_participant.as_ref(),
                    Some(&participant_for_probe),
                    &sink,
                    user_participant_identity.as_deref(),
                    &call_id,
                    &trace_id,
                    user_participant_identity.as_deref(),
                    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,
@@ -952,6 +1420,18 @@
                    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;
                    }
                }
@@ -962,14 +1442,29 @@
                    &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,
                    user_participant_identity.as_deref(),
                    controlled_fixture_lifecycle_active.clone(),
                )
                .await;
            }
@@ -1012,6 +1507,7 @@
            _ => {}
        }
    }
    controlled_fixture_lifecycle_active.store(false, Ordering::Release);
}

async fn process_controlled_fixture_probe(
@@ -1019,71 +1515,142 @@
    acknowledged_probe_sequences: &mut HashSet<String>,
    participant: Option<&RemoteParticipant>,
    sink: &BotAudioOutputSink,
    call_id: &str,
    trace_id: &str,
    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;
        return None;
    };
    if acknowledged_probe_sequences.contains(&probe.sequence) || Instant::now() > probe.expires_at {
        return;
    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;
        return None;
    };
    if participant.identity() != probe.sender {
        return;
    }
    let mut decision = Err("timeout");
    for attempt in 0..CONTROLLED_FIXTURE_PROBE_RECHECKS {
        if Instant::now() > probe.expires_at {
            break;
        }
        let attributes = participant.attributes();
        decision = classify_controlled_fixture_attributes(
            &participant.identity().to_string(),
            expected_participant,
            &attributes,
        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"),
        );
        if decision.is_ok() || !matches!(decision, Err("missing_attributes")) {
            break;
        }
        if attempt + 1 < CONTROLLED_FIXTURE_PROBE_RECHECKS {
            sleep(CONTROLLED_FIXTURE_PROBE_RECHECK_DELAY).await;
        }
        return Some(false);
    }
    let (result, input_source_category, reject_reason) = match decision {
        Ok(()) => ("observed", Some("controlled_fixture"), None),
        Err(reason) => ("rejected", None, Some(reason)),
    };
    let ack = ControlledFixtureAttributeAck {
        message_type: CONTROLLED_FIXTURE_ACK_TOPIC,
        protocol_version: CONTROLLED_FIXTURE_PROTOCOL_VERSION,
        call_id_hash: sha256_hex(call_id),
        call_trace_id_hash: sha256_hex(trace_id),
        generation: CONTROLLED_FIXTURE_GENERATION,
        client_fixture_sequence: probe.sequence.clone(),
        result,
        input_source_category,
        reject_reason,
    };
    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,
        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],
        destination_identities: vec![probe.sender.clone()],
    });
    if publish.await.is_ok() {
        acknowledged_probe_sequences.insert(probe.sequence);
    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(),
            sink.room.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(
@@ -4331,7 +4898,7 @@
mod tests {
    use super::*;
    use std::{
        collections::HashSet,
        collections::{HashMap, HashSet},
        io::{Read, Write},
        net::TcpListener,
        sync::{
@@ -4342,6 +4909,62 @@
        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() {
@@ -4879,6 +5502,9 @@
            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()
@@ -4951,6 +5577,545 @@
    }

    #[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_views(
            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()
                }
            },
            || Some(("user-1".to_string(), HashMap::new())),
        )
        .await;
        assert_eq!(acknowledged.len(), 1);
        assert_eq!(
            evidence,
            Some(ControlledFixtureVisibilityEvidence {
                first_visible_bucket: "250_500ms",
                visibility_source: "participant_attributes_poll",
                visibility_result: "held_visible",
                binding_matched: true,
            })
        );

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

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

        let inactive = Arc::new(AtomicBool::new(false));
        assert_eq!(
            observe_controlled_fixture_post_expiry_views(
                Instant::now(),
                Instant::now() + Duration::from_millis(50),
                "user-1",
                Some("user-1"),
                "fixture-01",
                inactive,
                HashMap::new,
                || Some(("user-1".to_string(), 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_result",
                "visibility_source",
            ]
        );
        let encoded = event.to_string();
        for forbidden in [
            "\"participant\":",
            "\"room\":",
            "\"track\":",
            "\"payload\":",
            "\"audio\":",
        ] {
            assert!(!encoded.contains(forbidden));
        }
    }

    #[tokio::test]
    async fn production_post_expiry_observation_distinguishes_held_stale_from_current_room_view() {
        let started_at = Instant::now();
        let current_attributes = 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-current-view",
            "runtime-trace-current-view",
            false,
            "timeout",
            Some("expired"),
            "call-current-view",
            "trace-current-view",
            CONTROLLED_FIXTURE_GENERATION,
            "fixture-01",
            &mut acknowledged,
        )
        .await;
        let evidence = observe_controlled_fixture_post_expiry_views(
            started_at,
            started_at + Duration::from_millis(100),
            "user-1",
            Some("user-1"),
            "fixture-01",
            Arc::new(AtomicBool::new(true)),
            HashMap::new,
            || Some(("user-1".to_string(), current_attributes.clone())),
        )
        .await;

        assert_eq!(
            expired_ack,
            ControlledFixtureAckPublishOutcome {
                observed: false,
                published: true,
            }
        );
        assert_eq!(acknowledged.len(), 1);
        assert_eq!(
            evidence,
            Some(ControlledFixtureVisibilityEvidence {
                first_visible_bucket: "lte_250ms",
                visibility_source: "current_room_lookup",
                visibility_result: "held_stale_current_visible",
                binding_matched: true,
            })
        );
        let mut observer_starts = 0;
        assert!(!start_observer_after_controlled_fixture_probe(
            true,
            Some(expired_ack.observed),
            || observer_starts += 1,
        ));
        assert_eq!(observer_starts, 0);

        for current_view in [
            None,
            Some(("cross-call-user".to_string(), current_attributes.clone())),
            Some((
                "user-1".to_string(),
                HashMap::from([
                    (
                        "inputSourceCategory".to_string(),
                        "controlled_fixture".to_string(),
                    ),
                    (
                        "clientFixtureSequence".to_string(),
                        "fixture-old".to_string(),
                    ),
                ]),
            )),
        ] {
            assert_eq!(
                observe_controlled_fixture_post_expiry_views(
                    Instant::now(),
                    Instant::now() + Duration::from_millis(20),
                    "user-1",
                    Some("user-1"),
                    "fixture-01",
                    Arc::new(AtomicBool::new(true)),
                    HashMap::new,
                    || current_view.clone(),
                )
                .await,
                None
            );
        }
    }

    #[test]
    fn controlled_fixture_ack_payload_is_reliable_and_redacted() {
        let ack = ControlledFixtureAttributeAck {
            message_type: CONTROLLED_FIXTURE_ACK_TOPIC,
@@ -4998,4 +6163,76 @@
            "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"
        );
    }
}