File Operation MCP Server

import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'; import { z } from 'zod'; import { exec, ExecOptions } from 'child_process'; import { promisify } from 'util'; import { quote } from 'shell-quote'; const execPromise = promisify(exec); /** * Tool: Format Code * Registers the tool with the MCP server * @param server MCP server instance */ const registerTool = (server: McpServer) => { server.registerTool( 'format-code', { title: 'Format Code', description: "Formats one or more code files using Prettier, with options for a configuration path and a dry run.", inputSchema: { filePaths: z.string().describe("A space-separated string of file paths to format."), config_path: z.string().optional().describe("Path to a custom Prettier configuration file."), dry_run: z.boolean().optional().default(false).describe("If true, checks if files are formatted without making changes."), } }, async ({ filePaths, config_path, dry_run, }) => { const action = dry_run ? '--check' : '--write'; const fileList = filePaths.split(' '); const quotedFiles = fileList.map(f => quote([f])).join(' '); const command = `npx prettier ${action} ${quotedFiles} ${config_path ? `--config ${quote([config_path])}` : ''}`; try { const { stdout, stderr } = await execPromise(command); if (dry_run) { return { content: [{ type: 'text', text: 'All checked files are formatted.' }] }; } // In write mode, stdout lists the files that were formatted. return { content: [{ type: 'text', text: `Successfully formatted files:\n${stdout}` }] }; } catch (error: any) { // Prettier's --check exits with code 1 if files are unformatted. if (dry_run && error.code === 1 && error.stdout) { return { content: [{ type: 'text', text: `The following files need formatting:\n${error.stdout}` }], isError: true // Technically not an execution error, but indicates a failed check. }; } let errorMessage = `Error formatting files: ${error.message}\n`; if (error.stdout) errorMessage += `STDOUT:\n${error.stdout}\n`; if (error.stderr) errorMessage += `STDERR:\n${error.stderr}\n`; return { content: [{ type: 'text', text: errorMessage }], isError: true }; } } ); }; export default registerTool;