Godot MCP

Instructions

Implementation Reference

• src/index.ts:1852-1946 (handler)

  Handler function for the 'save_scene' tool. Validates inputs (projectPath, scenePath, optional newPath), checks project and scene existence, prepares parameters, executes the Godot operation via executeOperation('save_scene'), handles errors and returns success message with output.

  private async handleSaveScene(args: any) {
    // Normalize parameters to camelCase
    args = this.normalizeParameters(args);
    
    if (!args.projectPath || !args.scenePath) {
      return this.createErrorResponse(
        'Missing required parameters',
        ['Provide projectPath and scenePath']
      );
    }
  
    if (!this.validatePath(args.projectPath) || !this.validatePath(args.scenePath)) {
      return this.createErrorResponse(
        'Invalid path',
        ['Provide valid paths without ".." or other potentially unsafe characters']
      );
    }
  
    // If newPath is provided, validate it
    if (args.newPath && !this.validatePath(args.newPath)) {
      return this.createErrorResponse(
        'Invalid new path',
        ['Provide a valid new path without ".." or other potentially unsafe characters']
      );
    }
  
    try {
      // Check if the project directory exists and contains a project.godot file
      const projectFile = join(args.projectPath, 'project.godot');
      if (!existsSync(projectFile)) {
        return this.createErrorResponse(
          `Not a valid Godot project: ${args.projectPath}`,
          [
            'Ensure the path points to a directory containing a project.godot file',
            'Use list_projects to find valid Godot projects',
          ]
        );
      }
  
      // Check if the scene file exists
      const scenePath = join(args.projectPath, args.scenePath);
      if (!existsSync(scenePath)) {
        return this.createErrorResponse(
          `Scene file does not exist: ${args.scenePath}`,
          [
            'Ensure the scene path is correct',
            'Use create_scene to create a new scene first',
          ]
        );
      }
  
      // Prepare parameters for the operation (already in camelCase)
      const params: any = {
        scenePath: args.scenePath,
      };
  
      // Add optional parameters
      if (args.newPath) {
        params.newPath = args.newPath;
      }
  
      // Execute the operation
      const { stdout, stderr } = await this.executeOperation('save_scene', params, args.projectPath);
  
      if (stderr && stderr.includes('Failed to')) {
        return this.createErrorResponse(
          `Failed to save scene: ${stderr}`,
          [
            'Check if the scene file is valid',
            'Ensure you have write permissions to the output path',
            'Verify the scene can be properly packed',
          ]
        );
      }
  
      const savePath = args.newPath || args.scenePath;
      return {
        content: [
          {
            type: 'text',
            text: `Scene saved successfully to: ${savePath}\n\nOutput: ${stdout}`,
          },
        ],
      };
    } catch (error: any) {
      return this.createErrorResponse(
        `Failed to save scene: ${error?.message || 'Unknown error'}`,
        [
          'Ensure Godot is installed correctly',
          'Check if the GODOT_PATH environment variable is set correctly',
          'Verify the project path is accessible',
        ]
      );
    }
  }

• src/index.ts:877-892 (schema)

  Input schema definition for the 'save_scene' tool, specifying required projectPath and scenePath, optional newPath.

  type: 'object',
  properties: {
    projectPath: {
      type: 'string',
      description: 'Path to the Godot project directory',
    },
    scenePath: {
      type: 'string',
      description: 'Path to the scene file (relative to project)',
    },
    newPath: {
      type: 'string',
      description: 'Optional: New path to save the scene to (for creating variants)',
    },
  },
  required: ['projectPath', 'scenePath'],

• src/index.ts:956-957 (registration)

  Registration of the 'save_scene' handler in the CallToolRequestSchema switch statement.

  case 'save_scene':
    return await this.handleSaveScene(request.params.arguments);

• src/index.ts:874-894 (registration)

  Tool registration in the ListToolsRequestSchema response, including name, description, and input schema.

    name: 'save_scene',
    description: 'Save changes to a scene file',
    inputSchema: {
      type: 'object',
      properties: {
        projectPath: {
          type: 'string',
          description: 'Path to the Godot project directory',
        },
        scenePath: {
          type: 'string',
          description: 'Path to the scene file (relative to project)',
        },
        newPath: {
          type: 'string',
          description: 'Optional: New path to save the scene to (for creating variants)',
        },
      },
      required: ['projectPath', 'scenePath'],
    },
  },

• src/index.ts:474-542 (helper)

  Helper function that executes Godot operations by spawning Godot with the operations script (godot_operations.gd) and the specific operation name ('save_scene') along with JSON parameters. This is the bridge to the actual Godot-side implementation.

  private async executeOperation(
    operation: string,
    params: OperationParams,
    projectPath: string
  ): Promise<{ stdout: string; stderr: string }> {
    this.logDebug(`Executing operation: ${operation} in project: ${projectPath}`);
    this.logDebug(`Original operation params: ${JSON.stringify(params)}`);
  
    // Convert camelCase parameters to snake_case for Godot script
    const snakeCaseParams = this.convertCamelToSnakeCase(params);
    this.logDebug(`Converted snake_case params: ${JSON.stringify(snakeCaseParams)}`);
  
  
    // Ensure godotPath is set
    if (!this.godotPath) {
      await this.detectGodotPath();
      if (!this.godotPath) {
        throw new Error('Could not find a valid Godot executable path');
      }
    }
  
    try {
      // Serialize the snake_case parameters to a valid JSON string
      const paramsJson = JSON.stringify(snakeCaseParams);
      // Escape single quotes in the JSON string to prevent command injection
      const escapedParams = paramsJson.replace(/'/g, "'\\''");
      // On Windows, cmd.exe does not strip single quotes, so we use
      // double quotes and escape them to ensure the JSON is parsed
      // correctly by Godot.
      const isWindows = process.platform === 'win32';
      const quotedParams = isWindows
        ? `\"${paramsJson.replace(/\"/g, '\\"')}\"`
        : `'${escapedParams}'`;
  
  
      // Add debug arguments if debug mode is enabled
      const debugArgs = GODOT_DEBUG_MODE ? ['--debug-godot'] : [];
  
      // Construct the command with the operation and JSON parameters
      const cmd = [
        `"${this.godotPath}"`,
        '--headless',
        '--path',
        `"${projectPath}"`,
        '--script',
        `"${this.operationsScriptPath}"`,
        operation,
        quotedParams, // Pass the JSON string as a single argument
        ...debugArgs,
      ].join(' ');
  
      this.logDebug(`Command: ${cmd}`);
  
      const { stdout, stderr } = await execAsync(cmd);
  
      return { stdout, stderr };
    } catch (error: unknown) {
      // If execAsync throws, it still contains stdout/stderr
      if (error instanceof Error && 'stdout' in error && 'stderr' in error) {
        const execError = error as Error & { stdout: string; stderr: string };
        return {
          stdout: execError.stdout,
          stderr: execError.stderr,
        };
      }
  
      throw error;
    }
  }