The sprint is complete only if all of these are true:

1. the open project `song.als` was used as the validation target
2. MCP editing tools were validated live, not just compiled
3. the open project received a real edit pass
4. harmonic MIDI backbone exists in Arrangement and covers materially more of the song
5. silence islands and mirrored symmetry were measured before and after
6. the result is less empty and less repetitive without losing structure
7. sound selection logic for aggressive snares became more selective instead of a blind blacklist
8. all changed Python files compile
9. relevant tests pass
10. the report includes exact MCP calls used on the open project
11. the report includes exact before/after coherence metrics
12. Codex final verdict is `pass`
