AbletonMCP

Instructions

Implementation Reference

• MCP_Server/server.py:410-439 (handler)

  Primary MCP tool handler function that executes the 'load_instrument_or_effect' tool by proxying a 'load_browser_item' command to the Ableton remote script socket server.
  @mcp.tool() def load_instrument_or_effect(ctx: Context, track_index: int, uri: str) -> str: """ Load an instrument or effect onto a track using its URI. Parameters: - track_index: The index of the track to load the instrument on - uri: The URI of the instrument or effect to load (e.g., 'query:Synths#Instrument%20Rack:Bass:FileId_5116') """ try: ableton = get_ableton_connection() result = ableton.send_command("load_browser_item", { "track_index": track_index, "item_uri": uri }) # Check if the instrument was loaded successfully if result.get("loaded", False): new_devices = result.get("new_devices", []) if new_devices: return f"Loaded instrument with URI '{uri}' on track {track_index}. New devices: {', '.join(new_devices)}" else: devices = result.get("devices_after", []) return f"Loaded instrument with URI '{uri}' on track {track_index}. Devices on track: {', '.join(devices)}" else: return f"Failed to load instrument with URI '{uri}'" except Exception as e: logger.error(f"Error loading instrument by URI: {str(e)}") return f"Error loading instrument by URI: {str(e)}"
• AbletonMCP_Remote_Script/__init__.py:726-760 (helper)

  Core implementation in Ableton remote script that loads the browser item (instrument/effect) by URI onto the track using Ableton Live API. Invoked by the MCP tool via socket command 'load_browser_item'.
  def _load_browser_item(self, track_index, item_uri): """Load a browser item onto a track by its URI""" try: if track_index < 0 or track_index >= len(self._song.tracks): raise IndexError("Track index out of range") track = self._song.tracks[track_index] # Access the application's browser instance instead of creating a new one app = self.application() # Find the browser item by URI item = self._find_browser_item_by_uri(app.browser, item_uri) if not item: raise ValueError("Browser item with URI '{0}' not found".format(item_uri)) # Select the track self._song.view.selected_track = track # Load the item app.browser.load_item(item) result = { "loaded": True, "item_name": item.name, "track_name": track.name, "uri": item_uri } return result except Exception as e: self.log_message("Error loading browser item: {0}".format(str(e))) self.log_message(traceback.format_exc()) raise
• AbletonMCP_Remote_Script/__init__.py:761-801 (helper)

  Recursive helper function used by _load_browser_item to locate the browser item matching the given URI across browser categories.
  def _find_browser_item_by_uri(self, browser_or_item, uri, max_depth=10, current_depth=0): """Find a browser item by its URI""" try: # Check if this is the item we're looking for if hasattr(browser_or_item, 'uri') and browser_or_item.uri == uri: return browser_or_item # Stop recursion if we've reached max depth if current_depth >= max_depth: return None # Check if this is a browser with root categories if hasattr(browser_or_item, 'instruments'): # Check all main categories categories = [ browser_or_item.instruments, browser_or_item.sounds, browser_or_item.drums, browser_or_item.audio_effects, browser_or_item.midi_effects ] for category in categories: item = self._find_browser_item_by_uri(category, uri, max_depth, current_depth + 1) if item: return item return None # Check if this item has children if hasattr(browser_or_item, 'children') and browser_or_item.children: for child in browser_or_item.children: item = self._find_browser_item_by_uri(child, uri, max_depth, current_depth + 1) if item: return item return None except Exception as e: self.log_message("Error finding browser item by URI: {0}".format(str(e))) return None