Xcode MCP Server

Instructions

Implementation Reference

• src/index.ts:91-171 (handler)

  MCP CallToolRequestSchema handler that processes tool calls. For 'xcode_*' tools like 'xcode_list_simulators_json', strips 'xcode_' prefix and calls CommandExecutor.executeCommand with the remaining command name and arguments.
  this.server.setRequestHandler(CallToolRequestSchema, async (request) => { const { name, arguments: args } = request.params; try { // Handle web monitor tools if (name === 'start_web_monitor') { const result = await this.webMonitorManager.start(); return { content: [ { type: 'text', text: `${result.message}\n\nWeb interface available at: ${result.url}` } ] }; } if (name === 'stop_web_monitor') { const result = this.webMonitorManager.stop(); return { content: [ { type: 'text', text: result.message } ] }; } if (name === 'web_monitor_status') { const status = this.webMonitorManager.getStatus(); let text = status.running ? `Web monitor is running at ${status.url} (port ${status.port})` : 'Web monitor is not running'; return { content: [ { type: 'text', text: text } ] }; } // Handle Xcode commands // Remove 'xcode_' prefix if present const commandName = name.startsWith('xcode_') ? name.slice(6) : name; const result = await this.commandExecutor.executeCommand(commandName, args); let responseText = result.output; if (result.error) { responseText += `\n\nWarnings/Errors:\n${result.error}`; } if (!result.success) { responseText = `Command failed: ${result.error}\n\nCommand executed: ${result.command}`; } return { content: [ { type: 'text', text: responseText, }, ], }; } catch (error) { if (error instanceof McpError) { throw error; } const errorMessage = error instanceof Error ? error.message : String(error); return { content: [ { type: 'text', text: `Error: ${errorMessage}`, }, ], }; } });
• src/command-executor.ts:124-162 (handler)

  Core execution handler for individual commands (e.g., 'list_simulators_json'). Builds shell command from template, validates params, executes via child_process.exec, returns output/error.
  async executeCommand(name: string, args: Record<string, any> = {}): Promise<{ success: boolean; output: string; error?: string; command: string; }> { const command = this.getCommand(name); if (!command) { throw new Error(`Command '${name}' not found`); } this.validateParameters(command, args); // Handle internal commands if (command.command.startsWith('internal:')) { return await this.executeInternalCommand(command, args); } // Handle external commands const builtCommand = this.buildCommand(command, args); try { const { stdout, stderr } = await execAsync(builtCommand); return { success: true, output: stdout, error: stderr || undefined, command: builtCommand }; } catch (error) { return { success: false, output: '', error: error instanceof Error ? error.message : String(error), command: builtCommand }; } }
• src/command-executor.ts:281-306 (schema)

  Generates input schema and tool metadata for MCP registration. Creates tool names like 'xcode_list_simulators_json' from loaded command definitions with corresponding input schemas.
  generateMCPToolDefinitions(): Array<{ name: string; description: string; inputSchema: any; }> { return Object.entries(this.commands).map(([name, command]) => ({ name: `xcode_${name}`, description: command.description, inputSchema: { type: 'object', properties: command.parameters ? Object.fromEntries( Object.entries(command.parameters).map(([paramName, paramDef]) => [ paramName, { type: paramDef.type, description: paramDef.description, ...(paramDef.default !== undefined && { default: paramDef.default }) } ]) ) : {}, required: command.parameters ? Object.entries(command.parameters) .filter(([_, paramDef]) => paramDef.required) .map(([paramName]) => paramName) : [] } })); }
• src/index.ts:87-89 (registration)

  Registers all dynamically generated Xcode tools (including 'xcode_list_simulators_json') with MCP ListToolsRequestSchema handler.
  this.server.setRequestHandler(ListToolsRequestSchema, async () => ({ tools: [...tools, ...webMonitorTools], }));
• src/command-executor.ts:85-122 (helper)

  Helper that constructs the actual shell command string by replacing placeholders {param} in command templates with argument values, handling optionals, booleans, and cleanup.
  buildCommand(command: XcodeCommand, args: Record<string, any>): string { let builtCommand = command.command; // Replace required parameters if (command.parameters) { for (const [paramName, paramDef] of Object.entries(command.parameters)) { const value = args[paramName] !== undefined ? args[paramName] : paramDef.default; if (paramDef.type === 'boolean') { // Handle boolean parameters if (value === true) { // Replace placeholder with the template if true builtCommand = builtCommand.replace(`{${paramName}}`, paramDef.template || ''); } else { // Remove placeholder if false builtCommand = builtCommand.replace(`{${paramName}}`, ''); } } else if (value !== undefined && value !== null && value !== '') { if (paramDef.template) { // Use custom template for parameter const paramValue = paramDef.template.replace(`{${paramName}}`, value); builtCommand = builtCommand.replace(`{${paramName}}`, paramValue); } else { // Direct replacement builtCommand = builtCommand.replace(`{${paramName}}`, value); } } else { // Remove optional parameter placeholders builtCommand = builtCommand.replace(new RegExp(`\\s*\\{${paramName}\\}`, 'g'), ''); } } } // Clean up any remaining placeholder patterns builtCommand = builtCommand.replace(/\s+/g, ' ').trim(); return builtCommand; }