TypeScript Definition Finder MCP server

This MCP server allows you to find TypeScript symbol definitions in your codebase, making it easier to locate original definitions of imported symbols, classes, interfaces, or functions. It's specifically designed to integrate with AI code editors for a more efficient coding experience.

Prerequisites

• Bun v1.2.2 or later
• Node.js for running the compiled server

Installation

Installing via Smithery

To install TypeScript Definition Finder for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install @runninghare/ts-def-mcp --client claude

Manual Installation

1. Install dependencies:

bun install

2. Build the project:

bun run build

Usage

Start the stdio server:

node dist/run.js

Tool Description

The server provides a find_typescript_definition tool with the following capabilities:

• Tool Name: find_typescript_definition
• Trigger Command: /ts-def (Useful in Cursor if you want to force AI editor to find the referenced symbol definition)
• Purpose: Locates the original definition of TypeScript symbols in your codebase

Input Parameters

The tool requires three parameters:

• file_path (string):

  • The absolute path to the current TypeScript file
  • Example: /path/to/your/project/src/index.ts

• line_content (string):

  • The entire line containing the symbol you want to find the definition of
  • Used to locate the correct line in the file
  • Must match the line exactly as it appears in the file

• column_number (number):

  • The 1-based column number where the symbol starts
  • Must be the exact column position of the symbol's first character

Examples

Finding an Imported Symbol Definition

Given this import statement:

import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";

To find the definition of StdioServerTransport, which starts at column 10, you would use:

{
  "file_path": "~/my-mcp-project/src/index.ts",
  "line_content": "import { StdioServerTransport } from \"@modelcontextprotocol/sdk/server/stdio.js\";",
  "column_number": 10
}

The output of this tool will be:

[
  {
    "file": "~/my-mcp-project/node_modules/@modelcontextprotocol/sdk/dist/esm/server/stdio.d.ts",
    "type": "Definition",
    "location": "Line 9, Column 22",
    "codeSnippet": "   8    */\n   9 > export declare class StdioServerTransport implements Transport {\n  10 +     private _stdin;\n  11 +     private _stdout;\n  12 +     private _readBuffer;\n  13 +     private _started;\n  14 +     constructor(_stdin?: Readable, _stdout?: Writable);\n  15 +     onclose?: () => void;\n  16 +     onerror?: (error: Error) => void;\n  17 +     onmessage?: (message: JSONRPCMessage) => void;\n  18 +     _ondata: (chunk: Buffer) => void;\n  19 +     _onerror: (error: Error) => void;\n  20 +     /**\n  21 +      * Starts listening for messages on stdin.\n  22 +      */\n  23 +     start(): Promise<void>;\n  24 +     private processReadBuffer;\n  25 +     close(): Promise<void>;\n  26 +     send(message: JSONRPCMessage): Promise<void>;\n  27   }\n"
  }
]

Finding a Local Symbol Definition

For a local class usage:

class MyService {
  private transport: StdioServerTransport;
}

To find the definition of StdioServerTransport, which starts at column 20, use:

{
  "file_path": "/path/to/project/src/service.ts",
  "line_content": "  private transport: StdioServerTransport;",
  "column_number": 20
}

Response Format

The tool returns a JSON response containing:

• The file path where the definition was found
• The line number of the definition
• The actual code snippet of the definition

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "ts-def-mcp" '{"command":"node","args":["dist/run.js"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "ts-def-mcp": {
            "command": "node",
            "args": [
                "dist/run.js"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "ts-def-mcp": {
            "command": "node",
            "args": [
                "dist/run.js"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect