mcp-joern

mcp-joern

5
securitydeveloper_tools

Joern MCP Server is designed as a Model Context Protocol server utilizing Joern for code review and security analysis. It offers an environment built for developers to efficiently manage and analyze code. Users are encouraged to contribute through issues and pull requests.

Joern MCP Server

A simple MCP Server for Joern.

Project Introduction

This project is an MCP Server based on Joern, providing a series of features to help developers with code review and security analysis.

Environment Requirements

  • Python >= 3.10 (default 3.12) & uv
  • Joern

Installation Steps

  1. Clone the project locally:

    git clone https://github.com/sfncat/mcp-joern.git
cd mcp-joern

  2. Install Python dependencies:

    uv venv .venv
source .venv/bin/activate
uv sync

Project Structure

├── server.py                       # MCP Server main program
├── test_mcp_client.py              # Test program for joern server and mcp tool
├── test_sc_tools.py                # Direct test program for sc tools
├── common_tools.py                 # Common utility functions
├── server_tools.py                 # Server utility functions
├── server_tools.sc                 # Scala implementation of server utility functions
├── server_tools_source.sc          # Scala implementation of server utility functions,use sourceCode to get the source code of method
├── requirements.txt                # Python dependency file
├── sample_cline_mcp_settings.json  # Sample cline mcp configuration file
└── env_example.txt                 # Environment variables example file

Usage

  1. Start the Joern server:

    joern -J-Xmx40G --server --server-host 127.0.0.1 --server-port 16162 --server-auth-username user --server-auth-password password --import server_tools.sc
Or
joern -J-Xmx40G --server --server-host 127.0.0.1 --server-port 16162 --server-auth-username user --server-auth-password password --import server_tools_source.sc

  2. Copy env_example.txt to .env Modify the configuration information to match the joern server startup configuration

  3. Run the test connection: Modify the information in test_mcp_client.py to confirm the joern server is working properly

    uv run test_mcp_client.py
Starting MCP server test...
==================================================
Testing server connection...
[04/16/25 20:38:54] INFO     Processing request of type CallToolRequest                                                                                                                     server.py:534
Connection test result: Successfully connected to Joern MCP, joern server version is XXX

  4. Configure MCP server Configure the mcp server in cline, refer to sample_cline_mcp_settings.json.

  5. Use MCP server Ask questions to the large language model, refer to prompts_en.md

Development Notes

  • .env file is used to store environment variables
  • .gitignore file defines files to be ignored by Git version control
  • pyproject.toml defines the Python configuration for the project
  • MCP tool development
    • Implement in server_tools.sc, add definitions in server_tools.py, and add tests in test_mcp_client.py

Contribution Guidelines

Welcome to submit Issues and Pull Requests to help improve the project.

Welcome to add more tools.

References

https://github.com/flankerhqd/jebmcp

https://docs.joern.io/server/

https://docs.joern.io/interpreter/