GA Chords

/ga chords — GA Chord Theory Helper

Use this sub-command when a task involves chord symbols, progressions, or key relationships and you need ground-truth answers from the live GA domain services rather than reasoning from memory.

When to Use

• Writing test data and need the correct diatonic chords for a key
• Transposing a chord progression in a test file or example
• Verifying a chord symbol is well-formed before adding it to domain data
• Understanding what intervals make up a complex chord like C7#9b13

Step-by-Step Procedure

1. Parse a chord symbol

curl -sk -X POST https://localhost:7001/api/ga/eval \
  -H "Content-Type: application/json" \
  -d "$(jq -n --arg s 'invoke "domain.parseChord" (Map.ofList ["symbol", box "C7#9"])' '{script:$s}')"

Returns JSON like:

{"root":"C","quality":"dominant","components":["ext:7","alt:#9"],"bass":null}

Present as: C7#9 = root C, dominant 7th, sharp-9 extension.

2. Transpose a chord or progression

For a single chord:

invoke "domain.transposeChord" (Map.ofList ["symbol", box "Am7"; "semitones", box 5])
// → "Dm7"

For a full progression (e.g. Am F C G up 5 semitones), build a loop:

let chords = [| "Am"; "F"; "C"; "G" |]
chords |> Array.map (fun s ->
    match invoke "domain.transposeChord" (Map.ofList ["symbol", box s; "semitones", box 5]) with
    | Ok v  -> v :?> string
    | Error e -> sprintf "ERROR:%A" e)

Or run it as a single script via the eval endpoint.

3. Get diatonic chords for a key

invoke "domain.diatonicChords" (Map.ofList ["root", box "Bb"; "scale", box "major"])
// → [| "Bb"; "Cm"; "Dm"; "Eb"; "F"; "Gm"; "Adim" |]

Scale options: "major" · "minor" · "aeolian" · "natural minor"

Display the result as Roman numerals:

Key of Bb major:  I=Bb  ii=Cm  iii=Dm  IV=Eb  V=F  vi=Gm  vii°=Adim

4. Transpose an entire file's chord symbols

When the user has a file containing chord progressions (test files, YAML configs, markdown docs):