Analyze Progression

Tool name: analyze-progression

Analyzes a chord progression: returns the key, Roman numerals per chord, and detected cadences.

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. [\"Dm7\",\"G7\",\"Cmaj7\"]."
    },
    "keyHint": {
      "description": "Optional key hint like \"C major\" or \"A minor\". When omitted, the key is inferred.",
      "type": "string",
      "minLength": 1
    }
  },
  "required": [
    "chords"
  ],
  "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": {
    "key": {
      "type": "string",
      "description": "Detected (or hinted) key, e.g. \"C major\"."
    },
    "romanNumerals": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "Roman numeral label per chord, in order."
    },
    "cadences": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "type": {
            "type": "string",
            "enum": [
              "authentic",
              "perfect-authentic",
              "plagal",
              "half",
              "deceptive",
              "phrygian"
            ]
          },
          "index": {
            "type": "integer",
            "minimum": -9007199254740991,
            "maximum": 9007199254740991,
            "description": "Index of the resolving (second) chord."
          },
          "chords": {
            "type": "array",
            "prefixItems": [
              {
                "type": "string"
              },
              {
                "type": "string"
              }
            ]
          },
          "romans": {
            "type": "array",
            "prefixItems": [
              {
                "type": "string"
              },
              {
                "type": "string"
              }
            ]
          }
        },
        "required": [
          "type",
          "index",
          "chords",
          "romans"
        ],
        "additionalProperties": false
      },
      "description": "Detected cadences, each at the index of the resolving chord."
    },
    "modulations": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "fromIndex": {
            "type": "integer",
            "minimum": -9007199254740991,
            "maximum": 9007199254740991
          },
          "toIndex": {
            "type": "integer",
            "minimum": -9007199254740991,
            "maximum": 9007199254740991
          },
          "fromKey": {
            "type": "string"
          },
          "toKey": {
            "type": "string"
          },
          "pivot": {
            "type": "string"
          }
        },
        "required": [
          "fromIndex",
          "toIndex",
          "fromKey",
          "toKey"
        ],
        "additionalProperties": false
      },
      "description": "Detected key changes (empty in v1; reserved for a later phase)."
    }
  },
  "required": [
    "key",
    "romanNumerals",
    "cadences",
    "modulations"
  ],
  "additionalProperties": false
}