diatonic-chords

Diatonic Chords of a Key

When a user asks for the diatonic chords / "the seven chords in" / "all chords in" a major or minor key, call ga_dsl_eval with closure name domain.diatonicChords. Do NOT enumerate the chords mentally — the closure handles enharmonic spelling correctly (Gb major returns Cm, not B#m; F# minor returns G#°, not Ab°).

Calling the tool

Method: ga_dsl_eval

Args (flat key-value, all values as strings):

• closureName = "domain.diatonicChords"
• args.root — the tonic letter, with accidental if any: "C", "G", "Bb", "F#", "Eb".
• args.scale — "major" or "minor".

Example invocation:

ga_dsl_eval(closureName: "domain.diatonicChords",
            args: { "root": "C", "scale": "major" })

Returns a DslEvalResult. The Result field carries the seven chord symbols as a JSON array, in scale-degree order: ["C", "Dm", "Em", "F", "G", "Am", "B°"] for C major, ["Am", "B°", "C", "Dm", "Em", "F", "G"] for A minor (natural).

Phrasing variants → args

User says	root	scale
"diatonic chords in C major"	C	major
"the seven chords in G major"	G	major
"diatonic chords in A minor"	A	minor
"chords of Bb major"	Bb	major
"harmonic series of F# minor"	F#	minor

If the user names a key without specifying mode (e.g. "diatonic chords in C"), assume major. If they say "the key of X minor" or "X-minor", use minor.

After the closure returns

Format the answer briefly. Recommended shape:

The seven diatonic chords of C major are: I = C, ii = Dm, iii = Em, IV = F, V = G, vi = Am, vii° = B°.

For minor keys, label with lowercase Roman numerals: i, ii°, III, iv, v, VI, VII (natural minor).

Progression requests (Roman numerals → select degrees)

If the user asks for a specific progression by Roman numerals — e.g. "ii-V-I", "I-IV-V", "I-vi-IV-V" — still call the closure (it gives the correctly-spelled diatonic chords for the key), but then present only the requested degrees, in the order given, as the progression. Do not list all seven chords in this case.