Scythe MCP REAPER

Instructions

Trigger a REAPER action by name.

Available actions:
- Transport: play, stop, pause, record, rewind, forward
- Project: save, save_as, new_project, undo, redo
- Tracks: insert_track, delete_track, duplicate_track
- View: zoom_fit, toggle_mixer

Args:
    action_name: Name of the action to trigger

Implementation Reference

• scythe_mcp/server/main.py:296-314 (handler)

  MCP tool handler for 'trigger_action', automatically registered via @mcp.tool(). Delegates to ReaperBridge.trigger_action_by_name.

  @mcp.tool()
  def trigger_action(ctx: Context, action_name: str) -> str:
      """
      Trigger a REAPER action by name.
      
      Available actions:
      - Transport: play, stop, pause, record, rewind, forward
      - Project: save, save_as, new_project, undo, redo
      - Tracks: insert_track, delete_track, duplicate_track
      - View: zoom_fit, toggle_mixer
      
      Args:
          action_name: Name of the action to trigger
      """
      bridge = get_bridge()
      if bridge.trigger_action_by_name(action_name):
          return f"Triggered action: {action_name}"
      return f"Error: Unknown action '{action_name}'"

• scythe_mcp/server/reaper_bridge.py:27-59 (helper)

  Dictionary mapping action names (lowercased) to REAPER internal action IDs, used to resolve action_name to ID.

  REAPER_ACTIONS = {
      # Transport
      "play": 1007,
      "stop": 1016,
      "pause": 1008,
      "record": 1013,
      "rewind": 40042,
      "forward": 40043,
      "goto_start": 40042,
      "goto_end": 40043,
      
      # Tracks
      "insert_track": 40001,
      "insert_midi_track": 40001,  # Same as insert track
      "delete_track": 40005,
      "duplicate_track": 40062,
      
      # Items
      "insert_empty_item": 40142,
      "split_items": 40012,
      "delete_items": 40006,
      
      # View
      "zoom_fit": 40295,
      "toggle_mixer": 40078,
      
      # Project
      "save": 40026,
      "save_as": 40022,
      "new_project": 40023,
      "undo": 40029,
      "redo": 40030,
  }

• scythe_mcp/server/reaper_bridge.py:114-120 (helper)

  Resolves action name to ID using REAPER_ACTIONS and calls trigger_action.

  def trigger_action_by_name(self, name: str) -> bool:
      """Trigger a REAPER action by name."""
      action_id = REAPER_ACTIONS.get(name.lower())
      if action_id:
          return self.trigger_action(action_id)
      logger.warning(f"Unknown action: {name}")
      return False

• scythe_mcp/server/reaper_bridge.py:109-113 (helper)

  Sends OSC /action/{action_id} message to REAPER to execute the action.

  def trigger_action(self, action_id: int) -> bool:
      """Trigger a REAPER action by ID."""
      # OSC format: /action/_ID or /action/ID
      return self.send_osc(f"/action/{action_id}")