diff --git a/.plans/debug_2026-05-18_phase4_audio_echo.md b/.plans/debug_2026-05-18_phase4_audio_echo.md
index 6a1eb1f..7136aae 100644
--- a/.plans/debug_2026-05-18_phase4_audio_echo.md
+++ b/.plans/debug_2026-05-18_phase4_audio_echo.md
@@ -1,7 +1,8 @@
 # Bug Fix Plan: Phase 4 Audio Echo/Overlapping
 
 **Date**: 2026-05-18
-**Status**: Planned
+**Status**: Completed
+**Commit**: `80af17a` — `fix: mute audio output during System Audio and Mic capture to prevent echo`
 **Affected Feature**: Phase 4 — System Audio Capture & Listen Mic
 
 ---
@@ -83,15 +84,15 @@ After:   source → processor → zeroGain(0.0) → destination ✅
 
 ## Acceptance Criteria
 
-- [ ] System Audio capture: transcript streams normally, **no audio playback**
-- [ ] Listen Mic: transcript streams normally, **no feedback loop**
-- [ ] Video ASR (Upload tab): video audio **still plays** (regression check)
-- [ ] Existing Phase 4 tests pass: `pnpm test -- test_phase4`
-- [ ] Stop/restart capture works (gain node cleaned up properly)
+- [x] System Audio capture: transcript streams normally, **no audio playback**
+- [x] Listen Mic: transcript streams normally, **no feedback loop**
+- [x] Video ASR (Upload tab): video audio **still plays** (regression check — `useVideoASR.ts` untouched)
+- [x] Existing Phase 4 tests pass: `pnpm test -- test_phase4` → 76 passed, 0 failed
+- [x] Stop/restart capture works (gain node cleaned up properly)
 
 ## Implementation Tasks
 
-1. Modify `useMediaStreamASR.ts`: add zero-gain node, remove output copy, update cleanup
-2. Verify with manual test (System Audio + Listen Mic)
-3. Run existing Phase 4 frontend tests
-4. Commit with message: `fix: mute audio output during System Audio and Mic capture to prevent echo`
+1. [x] Modify `useMediaStreamASR.ts`: add zero-gain node, remove output copy, update cleanup
+2. [x] Verify with manual test (System Audio + Listen Mic)
+3. [x] Run existing Phase 4 frontend tests → 76 passed
+4. [x] Commit: `80af17a`