# Music Theory Scale Speller

> Music Theory Scale Speller is a paid API for AI agents from music-theory.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Returns the notes, degrees, semitone intervals, step patterns, MIDI numbers, and pitch classes for any named scale or mode on a given root note.

## Facts

- Endpoint: GET https://music-theory.x402tookit.com/scale?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/music-theory-scale-speller-e44bfb96
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4YPWiOD5T3q9U7Rq3HuY3

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability music-theory-scale-speller-e44bfb96
```

Example prompt: What are the notes in an F# harmonic minor scale? Give me the degrees, semitone intervals, and step pattern too.

## When to prefer this

Use this endpoint when you need the canonical spelling of a scale or mode — its note names, degrees, intervals, and MIDI values — for any root. It covers a broad set of scale types including modes, harmonic and melodic minor, pentatonic, blues, and whole tone, making it the right choice for music theory lookups, educational tools, composition assistants, and audio software that needs ground-truth scale data.

## Known failure modes

- Missing required 'root' query parameter returns an error
- Unrecognized scale type name may return an error or fall back to major
- Invalid root note format (e.g. 'H', 'X') may return an error
- Payment failure (402) if USDC balance is insufficient or x402 auth is missing

## How this service works

Spell a scale or mode on any root: major, minor, modes, harmonic and melodic minor, pentatonic, blues, whole tone.

## Output

Returns a structured object with the root note, scale type, an array of note names (e.g. ['C','D','E','F','G','A','B']), scale degrees, semitones from root, step pattern string, pitch classes as integers, MIDI note numbers from octave 4, note count, and any known aliases for the scale.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "root"
     ],
     "properties": {
      "root": {
       "type": "string",
       "description": "Root note: C, F#, Bb, Eb"
      },
      "type": {
       "type": "string",
       "description": "Scale name (default major): major, natural-minor, dorian, phrygian, lydian, mixolydian, locrian, harmonic-minor, melodic-minor, major-pentatonic, minor-pentatonic, blues, major-blues, whole-tone, phrygian-dominant"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "root": {
       "type": [
        "null",
        "string"
       ]
      },
      "type": {
       "type": [
        "null",
        "string"
       ]
      },
      "notes": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "aliases": {
       "type": [
        "array",
        "null"
       ]
      },
      "degrees": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "noteCount": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
       
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/music-theory-scale-speller-e44bfb96/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from music-theory.x402tookit.com](https://www.zero.xyz/host/music-theory.x402tookit.com/llms.txt)