# Music Production Calc – Diatonic Chords

> Music Production Calc – Diatonic Chords is a paid API for AI agents from music-production-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Returns all 7 diatonic triads and 7th chords for a given key (major, natural minor, or harmonic minor) with spelled notes, Roman numerals, and chord qualities.

## Facts

- Endpoint: GET https://music-production-calc.x402tookit.com/diatonic-chords?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-production-calc-diatonic-chords-ea3fbcfc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pylQA3I41VPuO38q_1Sbj

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-production-calc-diatonic-chords-ea3fbcfc
```

Example prompt: What are all the diatonic triads and 7th chords in the key of F# minor (harmonic minor)? Give me the Roman numerals and the spelled-out notes for each chord.

## When to prefer this

Use this endpoint when you need the full set of diatonic chords for a key with precise note spelling, Roman numeral analysis, and chord quality labels — particularly useful for music theory lookups, chord progression generation, DAW session planning, or educational music tools. Prefer it over manual calculation when working with non-standard keys (e.g. Bb, F#, enharmonic spellings) or harmonic minor scale variants.

## Known failure modes

- Missing or unrecognized key parameter returns an error or null chords
- Ambiguous key notation (e.g. both 'Am' and 'A minor' should work, but malformed strings may fail)
- Unsupported scale type string returns default or error
- Network timeout or payment failure returns no data

## How this service works

The 7 triads and 7th chords of a key (major, natural or harmonic minor) with spelled notes and Roman numerals.

## Output

A structured list of 7 diatonic chord entries, each containing: scale degree number, Roman numeral (e.g. IIm7, V7, viidim7), triad name, seventh chord name, triad quality, triad notes array, seventh chord notes array, plus the scale notes used and the resolved scale type (major, natural minor, or harmonic minor).

## 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": [
      "key"
     ],
     "properties": {
      "key": {
       "type": "string",
       "description": "Key: C, F#, Bb, Am, F#m or 'Bb minor' (no mode means major)"
      },
      "scale": {
       "type": "string",
       "description": "major, minor (natural) or harmonic-minor; default follows the key's mode"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "key": {
       "type": [
        "null",
        "string"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "chords": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "object",
        "properties": {
         "roman": {
          "type": [
           "null",
           "string"
          ]
         },
         "triad": {
          "type": [
           "null",
           "string"
          ]
         },
         "degree": {
          "type": [
           "null",
           "number"
          ]
         },
         "seventh": {
          "type": [
           "null",
           "string"
          ]
         },
         "triadNotes": {
          "type": [
           "array",
           "null"
          ],
          "items": {
           "type": "string"
          }
         },
         "seventhNotes": {
          "type": [
           "array",
           "null"
          ],
          "items": {
           "type": "string"
          }
         },
         "triadQuality": {
          "type": [
           "null",
           "string"
          ]
         }
        }
       }
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "stri
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/music-production-calc-diatonic-chords-ea3fbcfc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from music-production-calc.x402tookit.com](https://www.zero.xyz/host/music-production-calc.x402tookit.com/llms.txt)