cadence.py
python
sha256:cf6265cea8c21d9228d90dec13ef6ec2dab5103d466db9cc4590681832de4bf8
docs(KD-STAGING): sync governance after KD-6b DONE
Human
12 days ago
| 1 | """muse cadence — cadence detection for a MIDI track. |
| 2 | |
| 3 | Identifies phrase endings (authentic, deceptive, half, plagal cadences) by |
| 4 | examining chord motions at bar boundaries. Agents composing or reviewing |
| 5 | multi-section music need automated cadence detection to enforce correct |
| 6 | phrase structure without listening to audio. |
| 7 | |
| 8 | Usage:: |
| 9 | |
| 10 | muse cadence tracks/chords.mid |
| 11 | muse cadence tracks/piano.mid --commit HEAD~1 |
| 12 | muse cadence tracks/strings.mid --json |
| 13 | |
| 14 | Output:: |
| 15 | |
| 16 | Cadence analysis: tracks/chords.mid — working tree |
| 17 | Found 3 cadences |
| 18 | |
| 19 | Bar Type From To |
| 20 | ────────────────────────────────────── |
| 21 | 5 authentic Gdom7 Cmaj |
| 22 | 9 half Cmaj Gdom7 |
| 23 | 13 authentic Ddom7 Gmaj |
| 24 | """ |
| 25 | |
| 26 | from __future__ import annotations |
| 27 | |
| 28 | import argparse |
| 29 | import json |
| 30 | import logging |
| 31 | import pathlib |
| 32 | import sys |
| 33 | |
| 34 | from muse.core.errors import ExitCode |
| 35 | from muse.core.repo import read_repo_id, require_repo |
| 36 | from muse.core.store import read_current_branch, resolve_commit_ref |
| 37 | from muse.plugins.midi._analysis import detect_cadences |
| 38 | from muse.plugins.midi._query import load_track, load_track_from_workdir |
| 39 | |
| 40 | logger = logging.getLogger(__name__) |
| 41 | |
| 42 | |
| 43 | |
| 44 | def _read_branch(root: pathlib.Path) -> str: |
| 45 | return read_current_branch(root) |
| 46 | |
| 47 | |
| 48 | def register(subparsers: "argparse._SubParsersAction[argparse.ArgumentParser]") -> None: |
| 49 | """Register the cadence subcommand.""" |
| 50 | parser = subparsers.add_parser("cadence", help="Detect phrase-ending cadences in a MIDI track.", description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter) |
| 51 | parser.add_argument("track", metavar="TRACK", help="Workspace-relative path to a .mid file.") |
| 52 | parser.add_argument("--commit", "-c", metavar="REF", default=None, dest="ref", help="Analyse a historical snapshot instead of the working tree.") |
| 53 | parser.add_argument("--json", action="store_true", dest="as_json", help="Emit results as JSON.") |
| 54 | parser.set_defaults(func=run) |
| 55 | |
| 56 | |
| 57 | def run(args: argparse.Namespace) -> None: |
| 58 | """Detect phrase-ending cadences in a MIDI track. |
| 59 | |
| 60 | ``muse cadence`` identifies authentic, deceptive, half, and plagal |
| 61 | cadences by examining chord motions at phrase boundaries (every 4 bars). |
| 62 | |
| 63 | Agents can use this to: |
| 64 | - Verify that phrase structure matches an intended form. |
| 65 | - Flag compositions where phrase endings lack proper resolution. |
| 66 | - Compare cadence patterns across branches to detect structural drift. |
| 67 | |
| 68 | Git cannot do this — it has no concept of musical phrase structure. |
| 69 | """ |
| 70 | track: str = args.track |
| 71 | ref: str | None = args.ref |
| 72 | as_json: bool = args.as_json |
| 73 | |
| 74 | root = require_repo() |
| 75 | commit_label = "working tree" |
| 76 | |
| 77 | if ref is not None: |
| 78 | repo_id = read_repo_id(root) |
| 79 | branch = _read_branch(root) |
| 80 | commit = resolve_commit_ref(root, repo_id, branch, ref) |
| 81 | if commit is None: |
| 82 | print(f"❌ Commit '{ref}' not found.", file=sys.stderr) |
| 83 | raise SystemExit(ExitCode.USER_ERROR) |
| 84 | result = load_track(root, commit.commit_id, track) |
| 85 | commit_label = commit.commit_id[:8] |
| 86 | else: |
| 87 | result = load_track_from_workdir(root, track) |
| 88 | |
| 89 | if result is None: |
| 90 | print(f"❌ Track '{track}' not found or not a valid MIDI file.", file=sys.stderr) |
| 91 | raise SystemExit(ExitCode.USER_ERROR) |
| 92 | |
| 93 | notes, _tpb = result |
| 94 | if not notes: |
| 95 | print(f" (no notes found in '{track}')") |
| 96 | return |
| 97 | |
| 98 | cadences = detect_cadences(notes) |
| 99 | |
| 100 | if as_json: |
| 101 | print(json.dumps( |
| 102 | {"track": track, "commit": commit_label, "cadences": list(cadences)}, |
| 103 | indent=2, |
| 104 | )) |
| 105 | return |
| 106 | |
| 107 | print(f"\nCadence analysis: {track} — {commit_label}") |
| 108 | if not cadences: |
| 109 | print(" (no cadences detected — track may be too short or lack chords)") |
| 110 | return |
| 111 | |
| 112 | print(f"Found {len(cadences)} cadence{'s' if len(cadences) != 1 else ''}\n") |
| 113 | print(f" {'Bar':>4} {'Type':<14} {'From':<12} {'To':<12}") |
| 114 | print(" " + "─" * 46) |
| 115 | for c in cadences: |
| 116 | print(f" {c['bar']:>4} {c['cadence_type']:<14} {c['from_chord']:<12} {c['to_chord']:<12}") |
File History
1 commit
sha256:cf6265cea8c21d9228d90dec13ef6ec2dab5103d466db9cc4590681832de4bf8
docs(KD-STAGING): sync governance after KD-6b DONE
Human
12 days ago