MCP Server with File Search Tool

A Model Context Protocol (MCP) server implementation in Node.js using TypeScript. This server provides tools for AI models to interact with external systems, including a powerful file search capability.

Features

• 🚀 MCP Server: Implements the Model Context Protocol for AI model integration
• 🔍 File Search Tool: Search for keywords within text files with line number results
• 🔧 Question Tool: A tool for asking freeform questions to a chatbot service
• 🛠️ BaseTool Abstraction: A simple abstraction for creating new tools with Zod-based schema validation
• 🌐 HTTP & STDIO Transport: Supports both HTTP and STDIO transport modes for the MCP server
• 📝 TypeScript: Full TypeScript support with strict type checking
• 🎯 ESLint + Prettier: Code quality and formatting tools
• 📦 Modern Node.js: ES2020+ features and modern JavaScript

Prerequisites

• Node.js 18+
• npm or yarn

Installation

1. Clone and navigate to the project:

   cd chatbot-mcp

2. Install dependencies:

   npm install

3. Set up environment variables:

   cp env.example .env
   # Edit .env with your configuration

Usage

Development Mode

Run the server with hot reloading:

npm run dev

Production Build

Build the TypeScript code:

npm run build

Run the compiled JavaScript:

npm start

Testing with MCP Inspector

Test your tools using the MCP Inspector:

npx @modelcontextprotocol/inspector dist/index.js

Code Quality

Lint the code:

npm run lint

Fix linting issues:

npm run lint:fix

Format code:

npm run format

Project Structure

chatbot-mcp/
├── src/
│   ├── index.ts              # Main entry point
│   ├── server.ts             # MCP server setup
│   ├── tools/
│   │   ├── FileSearchTool.ts # File search tool implementation
│   │
│   └── utils/
│       ├── BaseTool.ts       # Base class for creating tools
│       └── toolRegistry.ts   # Utility to register all tools
├── sample.txt                # Sample file for testing file search
├── package.json              # Dependencies and scripts
├── tsconfig.json             # TypeScript configuration
├── .env.example              # Environment variables template
└── README.md                 # This file

MCP Tools

1. search_file (File Search Tool)

Searches for a specified keyword within a file and returns matching lines with line numbers.

Input Schema:

{
  filepath: string,           // Path to the file to search
  keyword: string,            // Keyword to search for
  caseSensitive?: boolean     // Whether search is case-sensitive (default: false)
}

Example Usage:

{
  "filepath": "sample.txt",
  "keyword": "MCP",
  "caseSensitive": false
}

Example Output:

Found 4 match(es) for keyword "MCP" in file: sample.txt

Line 1: Welcome to the MCP Server Documentation
Line 3: The Model Context Protocol enables seamless integration...
Line 5: MCP servers provide powerful capabilities...
Line 10: MCP makes it easy to build tool-enhanced AI applications.

Features:

• Case-insensitive search by default
• Returns line numbers with matching content
• Handles file not found errors gracefully
• Supports both absolute and relative file paths

HTTP Endpoints

• POST /mcp - The primary endpoint for MCP requests when in HTTP mode
• GET / - A simple message indicating the server is running

Configuration

Environment variables (set in .env file):

• PORT - The port for the MCP server to listen on (default: 5001)
• TRANSPORT_MODE - The transport mode for the server, either http or stdio (default: http)
• CHAT_SERVER_URL - The URL for the external chat service used by the questionTool

Development

Adding New Tools

1. Create a new tool file in src/tools/
2. Extend the BaseTool class
3. Define the input schema using Zod
4. Implement the execute method
5. Register the tool in src/utils/toolRegistry.ts

Example Tool Structure

// src/tools/myNewTool.ts
import { BaseTool } from '../utils/BaseTool';
import { z } from 'zod';

export class MyNewTool extends BaseTool {
  constructor() {
    super({
      name: 'my_new_tool',
      title: 'My New Tool',
      description: 'A description for the new tool',
      inputSchema: {
        parameter1: z.string().describe('Description for parameter 1'),
        parameter2: z.number().optional().describe('Optional parameter')
      }
    });
  }

  async execute(input: any): Promise<any> {
    const { parameter1, parameter2 } = input;
    // Your tool's logic here
    return { success: true, result: `Received ${parameter1}` };
  }
}

File Search Tool Implementation

The File Search Tool demonstrates:

• File system operations using Node.js fs module
• Error handling for missing files
• String manipulation and search algorithms
• Case-sensitive and case-insensitive search options
• Formatted output with line numbers

Testing the File Search Tool

1. Create a test file (sample.txt):

   Welcome to the MCP Server Documentation
   This is a sample file for testing.
   The Model Context Protocol enables seamless integration.
   You can search for any keyword in this file.
   MCP servers provide powerful capabilities.
   

2. Run the MCP Inspector:

   npx @modelcontextprotocol/inspector dist/index.js

3. Test with sample input:

   • filepath: sample.txt or full path to the file
   • keyword: MCP
   • caseSensitive: false

4. Verify the output shows all matching lines with line numbers

MCP Protocol

This server implements the Model Context Protocol, allowing AI models to:

• Discover available tools
• Call tools with structured inputs
• Receive structured outputs
• Handle errors gracefully

The server can be configured to use either stdio or http transport, making it flexible for different MCP client implementations.

Troubleshooting

Common Issues

1. Port already in use: Change the PORT variable in your .env file
2. TypeScript compilation errors: Run npm run lint to see detailed errors
3. File not found: Use absolute paths or ensure relative paths are correct
4. MCP connection issues: Ensure the server is running and transport mode is correct

Logs

The server provides detailed logging for debugging:

• MCP server initialization
• Tool execution and results
• File operations
• Error details with stack traces

Use Cases

File Search Tool Applications

• Code Review: Search for specific patterns or keywords in source code
• Log Analysis: Find error messages or specific events in log files
• Documentation: Locate specific information in text documents
• Configuration: Search for settings in configuration files
• Data Processing: Find specific entries in CSV or text data files

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Run tests and linting
5. Submit a pull request

Resources

• Model Context Protocol
• MCP SDK Documentation
• Node.js File System
• TypeScript
• Zod Schema Validation

Author: Parthik Diyora
Date: November 2, 2025