Compose

Load reference material. Always read:

• .claude/skills/compose/gm-samples.md — valid instrument sample names (for source: 'sampled')
• .claude/skills/compose/genre-guide.md — genre conventions, progressions, drum patterns

If the request involves EDM, synths, effects, automation, sidechain, LFO modulation, or one-shot drums, also read:

• .claude/skills/compose/synth-presets.md — 14 starter synth patches with role hints
• .claude/skills/compose/effects-reference.md — the 12 supported effect types with params and usage patterns
• .claude/skills/compose/modulation-patterns.md — wobble bass, sidechain pumping, filter sweeps, drops
• .claude/skills/compose/oneshot-hits.md — bundled CC0 drum/FX samples available via source: 'oneshot'

Optional starter templates: if the request names a specific genre that has a starter kit and you want a base to adapt rather than building from scratch, also read:

• .claude/skills/compose/genre-templates.md — opt-in starter kits for house, bass house, dubstep, drum & bass, future bass, and trance. Templates are starting points, not prescriptions — you're free to deviate, swap instruments, change progressions, or ignore them entirely. Skip this file for non-listed genres (lofi, trap, ambient, classical, etc.) or when the request is genre-agnostic.

Ask clarifying questions only if the request is very vague (e.g., bare "/compose"). If there's enough to work with, generate directly.

Generate the composition JSON. Follow the composition-format and music-theory rules. Key principles:

• Write every note — no placeholders or "repeat" comments
• Vary velocity across notes
• Build energy across sections (add instruments, raise dynamics)
• Keep instruments in their natural registers
• Ensure harmonic consistency across simultaneous instruments
• Always emit metadata.tags. Use the seed vocabulary in genre-guide.md. First tag is the primary genre, remaining tags are modifiers/moods/structural hints. Most compositions warrant 3–5 tags. Lowercase-hyphenated format enforced by the validator.

For compositions over ~32 bars or expected to exceed ~200 notes, reach for the helper library at tools/compose-helpers/ for repetitive scaffolding (drum grids, bass patterns, pad sustains, arpeggios, humanization). Write a throwaway scratch script (in /tmp/), import primitives you need, build repetitive tracks with them, and hand-write melodies, fills, and transitions on top. Helper output is a starting point — hand-edit for expression before finalizing. See tools/compose-helpers/README.md for the inventory and conventions. New helpers are encouraged — if a primitive you need doesn't exist yet, add it rather than reinventing ad-hoc code.

Rigidity pass. Before finalizing, scan the generated composition for mechanical uniformity and adjust. Applies regardless of whether helpers were used:

• Velocity uniformity: if >60% of notes in a track share the same velocity, apply a natural velocity curve (emphasize downbeats, soften offbeats, ghost notes between hits).
• Bar-to-bar identicalness: if 4+ consecutive bars are literal duplicates within a track, introduce one variation — a ghost note, a dropped hit, a velocity accent, a one-bar fill.
• Section contrast: each section should have at least one distinguishing element from its neighbors (instrumentation, density, dynamics, register, drum variation).
• Transition markers: every section boundary should have some audible marker — fill, crash, drop-out, sweep, automation point. Add one if none exist.

Write the JSON — draft-first. Author to /tmp/composition-draft-<slug>.json throughout generation. Validate against the schema. Then run pnpm finalize-composition <slug> as the final step — the helper copies the draft to compositions/<slug>.json and updates the composition index in one atomic operation. See .claude/rules/composition-drafts.md for the full convention and rationale.

Briefly describe what you created — title, key, BPM, instruments, section overview, and what the rigidity pass adjusted (or "rigidity pass clean" if no adjustments were needed). A few sentences max.