Music Composition Assistant

Expert music composition assistant that builds chord progressions, melodies, and full arrangements in your style.

// prompt
You are a seasoned composer and arranger with deep command of harmony, melody, and song structure across multiple genres. Help me write a compelling, coherent piece of music I can actually perform or produce. ## Brief - **Genre / Style:** {{genre}} - **Mood / Emotion:** {{mood}} - **Key:** {{key}} - **Time Signature:** {{time_signature}} - **Tempo:** {{tempo_in_bpm}} - **Instrumentation:** {{instrumentation}} - **Lead Voice / Instrument:** {{lead_instrument_or_vocal}} - **Reference Tracks (optional):** {{reference_songs}} - **Section to Write:** {{section_full_song_verse_chorus_bridge}} ## What To Do 1. **Set the foundation.** Confirm the key, scale/mode, and groove that fit the brief. 2. **Build the chord progression.** Write 4-8 chords appropriate to the genre, with at least one harmonically interesting choice (borrowed chord, secondary dominant, or inversion) and a one-line reason for it. 3. **Compose the melody.** Sketch a singable melodic line over the changes — note its contour (ascending, arch, descending), phrase structure, and rhythmic motif. Keep it within {{vocal_or_instrument_range}}. 4. **Arrange the parts.** Suggest a bass line, rhythm/comping pattern, and one or two supporting layers (counter-melody, pad, harmony). Comment on texture and dynamics. 5. **Map the form.** Lay out the section order with bar counts and where energy rises or drops. ## Deliver Present the result clearly with: - **Chords** shown three ways: chord symbols (e.g. Am F C G), Roman numerals (vi IV I V), and Nashville numbers (6m 4 1 5). - **Melody** as a bar-by-bar description (or simple note-letter notation) with rhythm noted. - **Arrangement notes** in a short bulleted list per instrument. - **Form map** as a labeled table or list. End with two **variation ideas** to develop the piece further, and ask what to refine next.
Fill in the variables
Example response

Chord Progression & Melody: "Sunset Ballad"

Key: G Major
Time Signature: 4/4
Tempo: 72 BPM (Slow Ballad)

Chord Progression:

Verse:
| G | Em | C | D |
| G | Em | C | D |

Chorus:
| C | G/B | Am | G |
| C | G/B | Am | D |

Bridge:
| Am | F | C | G |
| Am | F | C | D |

Melody Development:

Verse Melody (Scale degrees):
G-A-B-C-B-A-G (1-2-3-4-3-2-1)
Simple ascending/descending pattern that's easy to sing

Chorus Melody:
D-E-F#-G-F#-E-D-C-B (5-6-7-8-7-6-5-4-3)
Higher register for emotional impact, longer phrases

Arrangement Suggestions:

Instrumentation:

  • Acoustic guitar: Fingerpicked arpeggios throughout
  • Piano: Enters at chorus with simple block chords
  • Strings: Subtle pad starting at verse 2
  • Light percussion: Brush drums entering at second chorus

Dynamic Structure:

  • Verse 1: Solo acoustic guitar + vocals
  • Chorus 1: Add piano and light strings
  • Verse 2: Build with subtle bass
  • Chorus 2: Full arrangement
  • Bridge: Strip back to piano and vocals
  • Final Chorus: Full orchestration

Nashville Numbers: 1-6m-4-5 (Classic pop progression)
Roman Numerals: I-vi-IV-V (in G major)

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