Godot MCP

Instructions

Implementation Reference

• src/index.ts:896-912 (registration)

  Registers the 'get_uid' tool with its description and input schema in the ListTools response.

    name: 'get_uid',
    description: 'Get the UID for a specific file in a Godot project (for Godot 4.4+)',
    inputSchema: {
      type: 'object',
      properties: {
        projectPath: {
          type: 'string',
          description: 'Path to the Godot project directory',
        },
        filePath: {
          type: 'string',
          description: 'Path to the file (relative to project) for which to get the UID',
        },
      },
      required: ['projectPath', 'filePath'],
    },
  },

• src/index.ts:958-959 (registration)

  Registers the handler dispatch for 'get_uid' tool in the CallToolRequestSchema switch statement.

  case 'get_uid':
    return await this.handleGetUid(request.params.arguments);

• src/index.ts:1951-2055 (handler)

  Handler function that validates inputs, checks Godot version compatibility, and executes the underlying Godot script operation to retrieve the UID for a file in the project.

  private async handleGetUid(args: any) {
    // Normalize parameters to camelCase
    args = this.normalizeParameters(args);
    
    if (!args.projectPath || !args.filePath) {
      return this.createErrorResponse(
        'Missing required parameters',
        ['Provide projectPath and filePath']
      );
    }
  
    if (!this.validatePath(args.projectPath) || !this.validatePath(args.filePath)) {
      return this.createErrorResponse(
        'Invalid path',
        ['Provide valid paths without ".." or other potentially unsafe characters']
      );
    }
  
    try {
      // Ensure godotPath is set
      if (!this.godotPath) {
        await this.detectGodotPath();
        if (!this.godotPath) {
          return this.createErrorResponse(
            'Could not find a valid Godot executable path',
            [
              'Ensure Godot is installed correctly',
              'Set GODOT_PATH environment variable to specify the correct path',
            ]
          );
        }
      }
  
      // 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 file exists
      const filePath = join(args.projectPath, args.filePath);
      if (!existsSync(filePath)) {
        return this.createErrorResponse(
          `File does not exist: ${args.filePath}`,
          ['Ensure the file path is correct']
        );
      }
  
      // Get Godot version to check if UIDs are supported
      const { stdout: versionOutput } = await execAsync(`"${this.godotPath}" --version`);
      const version = versionOutput.trim();
  
      if (!this.isGodot44OrLater(version)) {
        return this.createErrorResponse(
          `UIDs are only supported in Godot 4.4 or later. Current version: ${version}`,
          [
            'Upgrade to Godot 4.4 or later to use UIDs',
            'Use resource paths instead of UIDs for this version of Godot',
          ]
        );
      }
  
      // Prepare parameters for the operation (already in camelCase)
      const params = {
        filePath: args.filePath,
      };
  
      // Execute the operation
      const { stdout, stderr } = await this.executeOperation('get_uid', params, args.projectPath);
  
      if (stderr && stderr.includes('Failed to')) {
        return this.createErrorResponse(
          `Failed to get UID: ${stderr}`,
          [
            'Check if the file is a valid Godot resource',
            'Ensure the file path is correct',
          ]
        );
      }
  
      return {
        content: [
          {
            type: 'text',
            text: `UID for ${args.filePath}: ${stdout.trim()}`,
          },
        ],
      };
    } catch (error: any) {
      return this.createErrorResponse(
        `Failed to get UID: ${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:474-542 (helper)

  Helper method that executes Godot operations via headless Godot with the godot_operations.gd script, used by get_uid to run the 'get_uid' operation.

  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;
    }
  }

• src/index.ts:399-407 (helper)

  Helper function used by get_uid handler to check if the Godot version supports UIDs (4.4+).

  private isGodot44OrLater(version: string): boolean {
    const match = version.match(/^(\d+)\.(\d+)/);
    if (match) {
      const major = parseInt(match[1], 10);
      const minor = parseInt(match[2], 10);
      return major > 4 || (major === 4 && minor >= 4);
    }
    return false;
  }