Proton Drive MCP

Instructions

Implementation Reference

• src/index.ts:335-360 (handler)

  Handler function for the 'write_file' tool: validates path, ensures parent directories exist, writes file content using Node.js fs/promises.writeFile, and returns success message or throws error.

  case 'write_file': {
    const writePath = validatePath(args?.path as string);
    const content = args?.content as string;
    
    try {
      // Create directory if needed
      await mkdir(dirname(writePath), { recursive: true });
      
      // Write the file
      await writeFile(writePath, content, 'utf-8');
      
      return {
        content: [
          {
            type: 'text',
            text: `Successfully wrote file: ${getRelativePath(writePath)}`,
          },
        ],
      };
    } catch (error: any) {
      throw new McpError(
        ErrorCode.InternalError,
        `Cannot write file: ${error.message}`
      );
    }
  }

• src/index.ts:162-175 (schema)

  Input schema for the 'write_file' tool defining required 'path' and 'content' string parameters.

  inputSchema: {
    type: 'object',
    properties: {
      path: { 
        type: 'string', 
        description: 'File path relative to Proton Drive root' 
      },
      content: { 
        type: 'string', 
        description: 'Text content to write to the file' 
      },
    },
    required: ['path', 'content'],
  },

• src/index.ts:159-176 (registration)

  Registration of the 'write_file' tool in the ListTools response, including name, description, and input schema.

  {
    name: 'write_file',
    description: 'Write or create a file in Proton Drive',
    inputSchema: {
      type: 'object',
      properties: {
        path: { 
          type: 'string', 
          description: 'File path relative to Proton Drive root' 
        },
        content: { 
          type: 'string', 
          description: 'Text content to write to the file' 
        },
      },
      required: ['path', 'content'],
    },
  },

• src/index.ts:91-111 (helper)

  Helper function validatePath used in write_file handler to resolve and secure the file path within Proton Drive root.

  function validatePath(relativePath: string): string {
    // Handle empty path
    if (!relativePath) {
      return PROTON_DRIVE_PATH;
    }
    
    // Clean the path - remove leading slashes and normalize
    const cleaned = relativePath
      .split(/[/\\]+/)
      .filter(Boolean)
      .join(sep);
    
    const fullPath = resolve(PROTON_DRIVE_PATH, cleaned);
    
    // Security check - ensure we're still within Proton Drive
    if (!fullPath.startsWith(PROTON_DRIVE_PATH)) {
      throw new Error('Invalid path: Access denied outside Proton Drive');
    }
    
    return fullPath;
  }