Interval / Chord / Scale Reference Builder implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-020

Effect

Computation or source lookup only

Input and validation requirements

The extreme-octave vector exceeds signed 64-bit MIDI range and must be rejected or handled with arbitrary precision; the interval vector also exposes an unspecified signed-versus-modulo direction convention.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "operation": "scale",
    "root": "C",
    "scale_type": "major"
  },
  "expected_outputs": {
    "notes": [
      "C",
      "D",
      "E",
      "F",
      "G",
      "A",
      "B"
    ],
    "scale_degrees": [
      1,
      2,
      3,
      4,
      5,
      6,
      7
    ],
    "pitch_classes": [
      0,
      2,
      4,
      5,
      7,
      9,
      11
    ]
  },
  "reference_data": {
    "root_pitch_class": {
      "C": 0,
      "source_convention": "Widely tabulated standard 12-TET music-theory value"
    },
    "major_scale_offsets_semitones": {
      "values": [
        0,
        2,
        4,
        5,
        7,
        9,
        11
      ],
      "source_convention": "Widely tabulated standard Western major-scale formula"
    },
    "pitch_class_note_names": {
      "values": [
        "C",
        "C-sharp/D-flat",
        "D",
        "D-sharp/E-flat",
        "E",
        "F",
        "F-sharp/G-flat",
        "G",
        "G-sharp/A-flat",
        "A",
        "A-sharp/B-flat",
        "B"
      ],
      "source_convention": "Widely tabulated standard 12-TET chromatic pitch-class convention"
    }
  },
  "working": "Start at C, pitch class 0. Add the major offsets: 0 -> 0 = C; 0+2=2 = D; 0+4=4 = E; 0+5=5 = F; 0+7=7 = G; 0+9=9 = A; 0+11=11 = B. Therefore the scale is C-D-E-F-G-A-B with degrees 1-7 and pitch classes [0,2,4,5,7,9,11]."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json