QGISMCP

Instructions

Implementation Reference

• src/qgis_mcp/qgis_mcp_server.py:230-235 (handler)

  The primary MCP tool handler for 'execute_processing'. This function is decorated with @mcp.tool() and proxies the processing request to the underlying QGIS socket server.

  def execute_processing(ctx: Context, algorithm: str, parameters: dict) -> str:
      """Execute a processing algorithm with the given parameters."""
      qgis = get_qgis_connection()
      result = qgis.send_command("execute_processing", {"algorithm": algorithm, "parameters": parameters})
      return json.dumps(result, indent=2)

• qgis_mcp_plugin/qgis_mcp_plugin.py:378-388 (handler)

  The core implementation in the QGIS plugin that executes the actual QGIS processing algorithm using processing.run().

  def execute_processing(self, algorithm, parameters, **kwargs):
      """Execute a processing algorithm"""
      try:
          import processing
          result = processing.run(algorithm, parameters)
          return {
              "algorithm": algorithm,
              "result": {k: str(v) for k, v in result.items()}  # Convert values to strings for JSON
          }
      except Exception as e:
          raise Exception(f"Processing error: {str(e)}")

• qgis_mcp_plugin/qgis_mcp_plugin.py:133-149 (registration)

  Internal registration of the execute_processing handler in the QGIS plugin's command handlers dictionary.

  handlers = {
      "ping": self.ping,
      "get_qgis_info": self.get_qgis_info,
      "load_project": self.load_project,
      "get_project_info": self.get_project_info,
      "execute_code": self.execute_code,
      "add_vector_layer": self.add_vector_layer,
      "add_raster_layer": self.add_raster_layer,
      "get_layers": self.get_layers,
      "remove_layer": self.remove_layer,
      "zoom_to_layer": self.zoom_to_layer,
      "get_layer_features": self.get_layer_features,
      "execute_processing": self.execute_processing,
      "save_project": self.save_project,
      "render_map": self.render_map,
      "create_new_project": self.create_new_project,
  }