MCP Ripgrep Server

Instructions

Implementation Reference

• src/index.ts:194-260 (handler)

  Handler for the 'search' tool: parses arguments, builds ripgrep command with options like case sensitivity, file pattern, max results, context, colors, executes it via exec(), processes output.

  case "search": {
    const pattern = String(args.pattern || "");
    const path = String(args.path);
    const caseSensitive = typeof args.caseSensitive === 'boolean' ? args.caseSensitive : undefined;
    const filePattern = args.filePattern ? String(args.filePattern) : undefined;
    const maxResults = typeof args.maxResults === 'number' ? args.maxResults : undefined;
    const context = typeof args.context === 'number' ? args.context : undefined;
    const useColors = typeof args.useColors === 'boolean' ? args.useColors : false;
    
    if (!pattern) {
      return {
        isError: true,
        content: [{ type: "text", text: "Error: Pattern is required" }]
      };
    }
    
    // Build the rg command with flags
    let command = "rg";
    
    // Add case sensitivity flag if specified
    if (caseSensitive === true) {
      command += " -s"; // Case sensitive
    } else if (caseSensitive === false) {
      command += " -i"; // Case insensitive
    }
    
    // Add file pattern if specified
    if (filePattern) {
      command += ` -g ${escapeShellArg(filePattern)}`;
    }
    
    // Add max results if specified
    if (maxResults !== undefined && maxResults > 0) {
      command += ` -m ${maxResults}`;
    }
    
    // Add context lines if specified
    if (context !== undefined && context > 0) {
      command += ` -C ${context}`;
    }
    
    // Add line numbers
    command += " -n";
    
    // Add color setting
    command += useColors ? " --color always" : " --color never";
    
    // Add pattern and path
    command += ` ${escapeShellArg(pattern)} ${escapeShellArg(path)}`;
    
    console.error(`Executing: ${command}`);
    const { stdout, stderr } = await exec(command);
    
    // If there's anything in stderr, log it for debugging
    if (stderr) {
      console.error(`ripgrep stderr: ${stderr}`);
    }
    
    return {
      content: [
        {
          type: "text",
          text: processOutput(stdout, useColors) || "No matches found"
        }
      ]
    };
  }

• src/index.ts:98-113 (registration)

  Registration of the 'search' tool in the tools list, including name, description, and full input schema.

    name: "search",
    description: "Search files for patterns using ripgrep (rg)",
    inputSchema: {
      type: "object",
      properties: {
        pattern: { type: "string", description: "The search pattern (regex by default)" },
        path: { type: "string", description: "Directory or file(s) to search." },
        caseSensitive: { type: "boolean", description: "Use case sensitive search (default: auto)" },
        filePattern: { type: "string", description: "Filter by file type or glob" },
        maxResults: { type: "number", description: "Limit the number of matching lines" },
        context: { type: "number", description: "Show N lines before and after each match" },
        useColors: { type: "boolean", description: "Use colors in output (default: false)" }
      },
      required: ["pattern", "path"]
    }
  },

• src/index.ts:100-111 (schema)

  Input schema for the 'search' tool defining parameters and requirements.

  inputSchema: {
    type: "object",
    properties: {
      pattern: { type: "string", description: "The search pattern (regex by default)" },
      path: { type: "string", description: "Directory or file(s) to search." },
      caseSensitive: { type: "boolean", description: "Use case sensitive search (default: auto)" },
      filePattern: { type: "string", description: "Filter by file type or glob" },
      maxResults: { type: "number", description: "Limit the number of matching lines" },
      context: { type: "number", description: "Show N lines before and after each match" },
      useColors: { type: "boolean", description: "Use colors in output (default: false)" }
    },
    required: ["pattern", "path"]

• src/index.ts:51-91 (helper)

  Helper function to execute shell commands safely using spawn, capturing stdout/stderr, handling ripgrep exit codes.

  function exec(command: string): Promise<{ stdout: string; stderr: string }> {
    return new Promise((resolve, reject) => {
      const parts = command.split(" ");
      const program = parts[0];
      const args = parts.slice(1).filter(arg => arg.length > 0);
      
      // Use spawn with explicit stdio control
      const child = spawn(program, args, {
        shell: true, // Use shell to handle quotes and escaping
      });
      
      let stdout = "";
      let stderr = "";
      
      child.stdout.setEncoding("utf8");
      child.stderr.setEncoding("utf8");
      
      child.stdout.on("data", (data) => {
        stdout += data;
      });
      
      child.stderr.on("data", (data) => {
        stderr += data;
      });
      
      child.on("close", (code) => {
        if (code === 0 || code === 1) { // Code 1 is "no matches" for ripgrep
          resolve({ stdout, stderr });
        } else {
          const error = new Error(`Command failed with exit code ${code}`);
          Object.assign(error, { code, stdout, stderr });
          reject(error);
        }
      });
      
      // Handle process errors
      child.on("error", (error) => {
        reject(error);
      });
    });
  }

• src/index.ts:41-45 (helper)

  Helper to escape shell arguments to prevent injection.

  function escapeShellArg(arg: string): string {
    // Replace all single quotes with the sequence: '"'"'
    // This ensures the argument is properly quoted in shell commands
    return `'${arg.replace(/'/g, "'\"'\"'")}'`;
  }