local-only server

The server can only run on the client’s local machine because it depends on local resources.

Integrations

Used for environment variable management, storing configuration information for connecting to the Joern server
Supports version control integration, used for cloning source code repositories for analysis
Provides the runtime environment for the MCP server, with utility functions and tools for code 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

Clone the project locally:
git clone https://github.com/sfncat/mcp-joern.git cd mcp-joern
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

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
Copy env_example.txt to .env Modify the configuration information to match the joern server startup configuration
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
Configure MCP server Configure the mcp server in cline, refer to sample_cline_mcp_settings.json.
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/

This server cannot be installed

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security - not tested

F

license - not found

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quality - not tested

A simple MCP (Multimodal Conversational Plugin) server based on Joern that provides code review and security analysis capabilities through natural language interfaces.

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