Ableton Remote Script — Python Bridge Patterns

Use this skill when implementing or reviewing code under live/AbletonMind/.

Constraints

• LiveAPI must be touched on Live's main thread. TCP worker threads enqueue work.
• Prefer stdlib only inside Live.
• Keep handlers idempotent and read-before-write.
• Wrap composite mutations in Song.begin_undo_step/end_undo_step.
• Return JSON-serializable data and structured JSON-RPC errors.
• Test offline with unittest and faked LiveAPI.

ControlSurface Lifecycle

Expose create_instance(c_instance), construct AbletonMind(ControlSurface), start the bridge when the control surface loads and stop it cleanly on disconnect/reload. Use log_message for structured diagnostics.

Handler Pattern

Register handlers with stable method names such as transport.play or track.list. Validate inputs, resolve Live objects at call time, check liveobj_valid before use, mutate only when needed, then read state back and return the contract shape.

Listener Pattern

Use a ListenerRegistry that tracks add/remove pairs. Subscribing twice is a no-op. Unsubscribe on client disconnect and surface reload. Listener callbacks push JSON-RPC notifications with stable event names and compact params.

Transactions

Use transaction helpers for multi-step mutations: create track + rename + load device should become one undo action. Always end the undo step in finally.

Tests

Every handler gets at least one happy path and one error path. Listener tests verify duplicate registration and cleanup. Smoke tests may use a real Live instance, but unit tests must pass without Live.