Cursor Agent MCP Server

Instructions

Implementation Reference

• server.js:324-336 (handler)

  Handler function for the cursor_agent_analyze_files tool. It destructures input args, composes a prompt listing the paths to analyze (with optional additional prompt), and invokes runCursorAgent to execute the underlying cursor-agent CLI.

  async (args) => {
    try {
      const { paths, prompt, output_format, cwd, executable, model, force, extra_args } = args;
      const list = Array.isArray(paths) ? paths : [paths];
      const composedPrompt =
        `Analyze the following paths in the repository:\n` +
        list.map((p) => `- ${String(p)}`).join('\n') + '\n' +
        (prompt ? `Additional prompt: ${String(prompt)}\n` : '');
      return await runCursorAgent({ prompt: composedPrompt, output_format, extra_args, cwd, executable, model, force });
    } catch (e) {
      return { content: [{ type: 'text', text: `Invalid params: ${e?.message || e}` }], isError: true };
    }
  },

• server.js:249-253 (schema)

  Zod input schema for cursor_agent_analyze_files: requires paths (single string or array of strings), optional prompt, and inherits common options like output_format, model, etc.

  const ANALYZE_FILES_SCHEMA = z.object({
    paths: z.union([z.string().min(1), z.array(z.string().min(1)).min(1)]),
    prompt: z.string().optional(),
    ...COMMON,
  });

• server.js:320-337 (registration)

  MCP server.tool registration for cursor_agent_analyze_files, including name, description, schema, and handler function.

  server.tool(
    'cursor_agent_analyze_files',
    'Analyze one or more paths; optional prompt. Prompt-based wrapper.',
    ANALYZE_FILES_SCHEMA.shape,
    async (args) => {
      try {
        const { paths, prompt, output_format, cwd, executable, model, force, extra_args } = args;
        const list = Array.isArray(paths) ? paths : [paths];
        const composedPrompt =
          `Analyze the following paths in the repository:\n` +
          list.map((p) => `- ${String(p)}`).join('\n') + '\n' +
          (prompt ? `Additional prompt: ${String(prompt)}\n` : '');
        return await runCursorAgent({ prompt: composedPrompt, output_format, extra_args, cwd, executable, model, force });
      } catch (e) {
        return { content: [{ type: 'text', text: `Invalid params: ${e?.message || e}` }], isError: true };
      }
    },
  );

• server.js:152-193 (helper)

  Helper function delegated by the handler; handles prompt execution via cursor-agent CLI, with arg normalization, env overrides, timeouts, and optional prompt echoing.

  // Accepts either a flat args object or an object with an "arguments" field (some hosts).
  async function runCursorAgent(input) {
    const source = (input && typeof input === 'object' && input.arguments && typeof input.prompt === 'undefined')
      ? input.arguments
      : input;
  
    const {
      prompt,
      output_format = 'text',
      extra_args,
      cwd,
      executable,
      model,
      force,
    } = source || {};
  
    const argv = [...(extra_args ?? []), String(prompt)];
    const usedPrompt = argv.length ? String(argv[argv.length - 1]) : '';
   
    // Optional prompt echo and debug diagnostics
    if (process.env.DEBUG_CURSOR_MCP === '1') {
      try {
        const preview = usedPrompt.slice(0, 400).replace(/\n/g, '\\n');
        console.error('[cursor-mcp] prompt:', preview);
        if (extra_args?.length) console.error('[cursor-mcp] extra_args:', JSON.stringify(extra_args));
        if (model) console.error('[cursor-mcp] model:', model);
        if (typeof force === 'boolean') console.error('[cursor-mcp] force:', String(force));
      } catch {}
    }
   
    const result = await invokeCursorAgent({ argv, output_format, cwd, executable, model, force });
   
    // Echo prompt either when env is set or when caller provided echo_prompt: true (if host forwards unknown args it's fine)
    const echoEnabled = process.env.CURSOR_AGENT_ECHO_PROMPT === '1' || source?.echo_prompt === true;
    if (echoEnabled) {
      const text = `Prompt used:\n${usedPrompt}`;
      const content = Array.isArray(result?.content) ? result.content : [];
      return { ...result, content: [{ type: 'text', text }, ...content] };
    }
   
    return result;
  }