generate_chord_progression

Create chord progressions for music composition by specifying a key and style like pop, jazz, or blues.

Instructions

Generate chord progression

Input Schema

TableJSON Schema

Name	Required	Description	Default
`key`	Yes	Key
`style`	Yes	Style (pop/jazz/blues/etc)

Implementation Reference

src/server/EnhancedMCPServerFixed.ts:834-842 (handler)

Handler executes validation, generates progression using MusicTheory, creates Strudel chord pattern using PatternGenerator, writes to editor, and returns summary.

case 'generate_chord_progression':
  InputValidator.validateRootNote(args.key);
  InputValidator.validateChordStyle(args.style);
  const progression = this.theory.generateChordProgression(args.key, args.style);
  const chordPattern = this.generator.generateChords(progression);
  const currentChords = await this.getCurrentPatternSafe();
  const newChordPattern = currentChords ? currentChords + '\n' + chordPattern : chordPattern;
  await this.writePatternSafe(newChordPattern);
  return `Generated ${args.style} progression in ${args.key}: ${progression}`;

src/server/EnhancedMCPServerFixed.ts:456-467 (registration)

Tool registration in getTools() array, including name, description, and input schema.

{
  name: 'generate_chord_progression',
  description: 'Generate chord progression',
  inputSchema: {
    type: 'object',
    properties: {
      key: { type: 'string', description: 'Key' },
      style: { type: 'string', description: 'Style (pop/jazz/blues/etc)' }
    },
    required: ['key', 'style']
  }
},

src/services/MusicTheory.ts:62-90 (helper)

Core method generates chord progression string from key and style using predefined progressions and chord mappings.

generateChordProgression(key: string, style: keyof typeof this.chordProgressions): string {
  const progression = this.chordProgressions[style];
  if (!progression) {
    throw new Error(`Invalid progression style: ${style}`);
  }
  
  const chordMap: Record<string, string> = {
    'I': `"${key}"`,
    'I7': `"${key}7"`,
    'i': `"${key.toLowerCase()}m"`,
    'ii': `"${this.getNote(key, 2)}m"`,
    'IIM7': `"${this.getNote(key, 2)}m7"`,
    'iii': `"${this.getNote(key, 4)}m"`,
    'III': `"${this.getNote(key, 4)}"`,
    'IV': `"${this.getNote(key, 5)}"`,
    'IV7': `"${this.getNote(key, 5)}7"`,
    'V': `"${this.getNote(key, 7)}"`,
    'V7': `"${this.getNote(key, 7)}7"`,
    'vi': `"${this.getNote(key, 9)}m"`,
    'VI': `"${this.getNote(key, 9)}"`,
    'VII': `"${this.getNote(key, 11)}"`,
    'bVII': `"${this.getNote(key, 10)}"`,
    'IM7': `"${key}maj7"`
  };

  return progression
    .map(chord => chordMap[chord] || `"${key}"`)
    .join(' ');
}

src/services/PatternGenerator.ts:124-134 (helper)

Helper converts chord progression string to Strudel pattern code with voicing options.

generateChords(progression: string, voicing: string = 'triad'): string {
  const voicings: Record<string, string> = {
    triad: '.struct("1 ~ ~ ~")',
    seventh: '.struct("1 ~ ~ ~").add(note("7"))',
    sustained: '.attack(0.5).release(2)',
    stab: '.struct("1 ~ 1 ~").release(0.1)',
    pad: '.attack(2).release(4).room(0.8)'
  };
  
  return `note(${progression}).s("sawtooth")${voicings[voicing] || voicings.triad}`;
}

src/server/EnhancedMCPServerFixed.ts:459-466 (schema)

Input schema defines required parameters key and style as strings.

inputSchema: {
  type: 'object',
  properties: {
    key: { type: 'string', description: 'Key' },
    style: { type: 'string', description: 'Style (pop/jazz/blues/etc)' }
  },
  required: ['key', 'style']
}

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