1 files changed, 3 insertions, 2 deletions
diff --git a/TODO.md b/TODO.md
index f97ef0e..0184f0a 100644
--- a/TODO.md
+++ b/TODO.md
@@ -16,9 +16,10 @@ Procedural spectrogram tool: 50-100× compression (5 KB .spec → ~100 bytes C++
 
 **Status:** 38/38 tests passing
 
-**Outstanding TODOs:**
+### ✅ Fix FFT twiddle factor accumulation bug (`src/audio/fft.cc`) — DONE
 
-1. **test_fft.cc:87** - Investigate FFT-DCT algorithm discrepancy
+`fft_radix2` now computes `wr = cosf(angle*k); wi = sinf(angle*k);` directly per k.
+Tests A–E added to `test_fft.cc`. `arrays_match` default tolerance reverted to 5e-3.
 
 ## Priority 4: Audio System Enhancements [LOW PRIORITY]