mcp-joern

mcp-joern

3.4

If you are the rightful owner of mcp-joern and would like to certify it and/or have it hosted online, please leave a comment on the right or send an email to henry@mcphub.com.

A simple MCP Server for Joern, providing features for code review and security analysis.

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/