Task 1 review flagged the new reflex module was missing from the
module-map //! catalogue. AGENTS.md learner-facing convention requires
the catalogue entry describing what the module does + why it exists.
Addresses the Minor finding from the Task 1 task review.
Signed-off-by: Aaron D. Lee <himself@adlee.work>
The critical-path foundation for the barge-in reflex. AdvisoryEvent is
the enum carried over a tokio mpsc from TapEngine to Reflex (brain →
FOB). ReflexMetrics is the observable surface. barge_in_flush is the
new AudioPipe trait method (default delegates to clear_playout_ring) —
the kill-now path that clears the ring AND drains rx_audio_out.
Task 1 of the slice-4 plan. Everything else depends on this landing.
Signed-off-by: Aaron D. Lee <himself@adlee.work>
Code-review findings from the slice-2 final whole-branch review:
- tap_client.rs: close arm sends session_end (not bye) per §5.2, awaits
brain bye with bounded 500ms timeout, then ws.close(). Promotes the
Task-7-documented Minor to Important's required spec compliance.
- session_map.rs: AppState::close() now clears channel.tap = None before
Closing->Closed, sends close signal, bounded-awaits engine task for the
teardown handshake (500ms cap), aborts as fallback. Per §5.1 step 5.
- pcm.rs + tap_audio_pipe.rs: AudioPipe trait gains clear_playout_ring()
(default no-op for EchoAudioPipe); TapAudioPipe clears the VecDeque.
RtcSession::clear_playout_ring delegates. Per §5.3 step 4 playout-on-
disconnect-flush contract.
- tap_engine.rs: spawn_tap_engine creates + shares a flush_tx mpsc
channel; run_engine_loop signals flush after each failed pump loop
(before backoff); TapConn.flush_rx is drained by drive_all_sessions
to call RtcSession::clear_playout_ring.
- tests/tap_integration.rs: new reconnect-path test asserts Channel
stays Connected, metrics.reconnect_attempts increments, playout
returns None during outage, playout resumes after EchoServer
restart with fresh frames (no stale bleed-through). Per §8.4.
- static/index.html: one static line acknowledging external-brain
routing per §7.2 (defer real-time tap status to step-3 GUI).
Spec ref: 2026-06-28-slice-2-agent-tap-design.md §5.1 step 5, §5.2, §5.3 step 4, §7.2, §8.4.
Two Important findings from the final whole-branch review:
T4-M3: RtcSession::channel_id/channel_state/is_closed lacked /// docs
(AGENTS.md mandates /// on every public item; learner-facing code is a
primary product). One-line docs added per existing /// style in rtc_session.rs.
T7-M2: README "Status" section still read "Scoping. No code yet" — stale
post-slice-1. Updated to reflect slice-1 implementation status; minimal
edit, surrounding content preserved.
Four routes on axum 0.7 per spec §4.1: POST /v1/sessions (mint),
POST /v1/sessions/:id/offer (str0m-native SDP accept), DELETE
/v1/sessions/:id (close), GET / (static HTML client). Session store is
a DashMap<ChannelId, Arc<Mutex<RtcSession>>> (spec §4.5); one tokio
task drives all session poll loops — per-session tasks would pre-pave
the wrong pattern for step 4's dedicated thread. Graceful shutdown
drops the DashMap on Ctrl-C / SIGTERM. Integration test exercises the
REST surface; manual browser e2e per README §6.5.
RtcSession owns a str0m::Rtc + Opus decoder/encoder + EchoAudioPipe +
a bound UDP socket (spec §3.1, §4.5). accept_offer calls str0m 0.21's
sdp_api().accept_offer() natively — no hand-rolled SDP munger; str0m
fills DTLS fingerprint + ICE creds + Opus codec. The loop driver
drains poll_output per str0m's single-mutation invariant, routes
inbound MediaData through Opus decode + EchoAudioPipe sink, sends
Transmit packets on the UDP socket, and checks the 60 s idle timeout.
DEV-DEVIATION: loop runs on tokio (spec §3.4); step 4 replaces with
a dedicated timing thread per ARCHITECTURE.md.
str0m 0.21 API adjustments from the brief's sketch (verified against
src/str0m-0.21.0):
- SdpAnswer has no .mid() accessor; use answer.media_lines[0].mid()
via the Deref<Target=Sdp> impl.
- Input::Receive carries the Instant as the first tuple element
(Input::Receive(now, recv)); handle_input takes a single Input arg.
- Receive constructed via Receive::new(proto, src, dst, buf) (the
DatagramRecv field is private).
- UDP socket binds 127.0.0.1:0 (Candidate::host rejects the
unspecified address 0.0.0.0).
- BROWSER_SDP_OFFER fixture restored a=group:BUNDLE 0 (str0m's
Sdp::assert_consistency rejects SDP without a session group).
PcmFrame is the canonical tap format (16-bit mono @ 24 kHz, 480 samples
per 20 ms frame — ARCHITECTURE.md). AudioSource/AudioSink are the seam
step 2 splices the tap client into (spec §3.3); EchoAudioPipe is the
slice-1 wiring of that seam. OpusDecoder/OpusEncoder wrap the opus
crate's libopus FFI with hot-path match-and-continue (no ? on the 20 ms
loop, spec §3.8); decode/encode return Option<PcmFrame>/Option<Vec<u8>>
so a dropped frame is logged + counted, never propagated to crash the
peer.
