Generate Bassline MIDI

Tool name: generate-bassline-midi

Renders a bassline (octave 2) under a chord progression to a Standard MIDI File (SMF1, 480 PPQ, 4/4).

Annotations

Hint	Value
readOnlyHint	✓
idempotentHint	✓
destructiveHint	—
openWorldHint	—

Input

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "chords": {
      "minItems": 1,
      "type": "array",
      "items": {
        "type": "string",
        "minLength": 1
      },
      "description": "Chord symbols in order (e.g. [\"Cmaj7\",\"Am7\",\"Dm7\",\"G7\"])."
    },
    "tempo": {
      "type": "integer",
      "minimum": 20,
      "maximum": 300,
      "description": "Tempo in BPM."
    },
    "style": {
      "type": "string",
      "enum": [
        "root",
        "root-fifth",
        "walking"
      ],
      "description": "Bass style. \"walking\" plays root–3rd–5th–chromatic-approach quarter notes; the approach targets the next chord on the last bar."
    },
    "barsPerChord": {
      "type": "integer",
      "minimum": 1,
      "maximum": 16,
      "description": "How many 4/4 bars each chord lasts."
    }
  },
  "required": [
    "chords",
    "tempo",
    "style",
    "barsPerChord"
  ],
  "additionalProperties": false
}

Output

Returned as structuredContent. The text rendering is a short human-readable summary.

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "midiBase64": {
      "type": "string",
      "description": "Base64-encoded Standard MIDI File bytes."
    },
    "format": {
      "type": "string",
      "const": "smf1",
      "description": "SMF format type 1."
    },
    "ppq": {
      "type": "number",
      "const": 480,
      "description": "Pulses per quarter note."
    },
    "durationMs": {
      "type": "integer",
      "minimum": 0,
      "maximum": 9007199254740991,
      "description": "Total duration in milliseconds."
    },
    "trackCount": {
      "type": "integer",
      "exclusiveMinimum": 0,
      "maximum": 9007199254740991,
      "description": "Number of MIDI tracks."
    }
  },
  "required": [
    "midiBase64",
    "format",
    "ppq",
    "durationMs",
    "trackCount"
  ],
  "additionalProperties": false
}