Scythe MCP REAPER

Instructions

Create a MIDI item on a track.

Args:
    track_number: Track number (1-based)
    position: Start position in beats
    length: Length in beats (default: 4 = 1 bar in 4/4)

Implementation Reference

• scythe_mcp/server/main.py:229-247 (handler)

  The main handler function for the 'create_midi_item' MCP tool. It is decorated with @mcp.tool(), defining the tool schema via its parameters and docstring. Calls ReaperBridge.insert_midi_item to perform the action.

  @mcp.tool()
  def create_midi_item(
      ctx: Context,
      track_number: int,
      position: float = 0.0,
      length: float = 4.0
  ) -> str:
      """
      Create a MIDI item on a track.
      
      Args:
          track_number: Track number (1-based)
          position: Start position in beats
          length: Length in beats (default: 4 = 1 bar in 4/4)
      """
      bridge = get_bridge()
      result = bridge.insert_midi_item(track_number - 1, position, length)
      return result.get("message", "MIDI item created")

• scythe_mcp/server/reaper_bridge.py:230-242 (helper)

  Supporting method in ReaperBridge class that handles the insertion of a MIDI item by writing a JSON command file for execution by a Lua script in REAPER.

  def insert_midi_item(self, track_index: int, position: float, length: float) -> Dict[str, Any]:
      """Insert MIDI item via file command."""
      self._write_command("insert_midi_item", {
          "track_index": track_index,
          "position": position,
          "length": length
      })
      
      response = self._read_response()
      if response:
          return response
      return {"success": True, "message": "MIDI item command sent"}