Joern MCP Server

[](https://mseep.ai/app/sfncat-mcp-joern) # Joern MCP Server A simple MCP Server for Joern. <a href="https://glama.ai/mcp/servers/@sfncat/mcp-joern"> <img width="380" height="200" src="https://glama.ai/mcp/servers/@sfncat/mcp-joern/badge" alt="Joern Server MCP server" /> </a> ## 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: ```bash git clone https://github.com/sfncat/mcp-joern.git cd mcp-joern ``` 2. Install Python dependencies: ```bash 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: ```bash 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 ``` If you are using it under Windows, you may need to set the JVM system variables through the command line or in the system environment variables. ``` set _JAVA_OPTIONS=-Dfile.encoding=UTF-8 ``` 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 ```bash 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/