JWT Auditor MCP Server
This project provides an MCP server exposing advanced JWT auditing tools, inspired by JWTAuditor. It is designed for use with Claude Desktop, Cursor, and other MCP-compatible clients.
Features
- JWT Decoder: Decodes JWT header, payload, and signature.
- JWT Analyzer: Detects vulnerabilities (alg=none, weak algs, missing claims, header injection, sensitive data, etc.).
- JWT Secret Bruteforcer: Attempts to brute-force HS256/HS384/HS512 secrets using a wordlist.
- JWT Generator/Editor: Create and sign JWTs (HS* and RS* support).
Quickstart
1. Install dependencies (using uv)
uv pip install -r pyproject.toml
2. Run the MCP server
uv run server.py
3. Configure Claude Desktop (or Cursor)
Add the following to your Claude Desktop mcpServers.json
(or merge into your config):
{
"mcpServers": {
"JWT Auditor MCP": {
"type": "stdio",
"command": "uv",
"args": ["run", "server.py"],
"cwd": "/Users/haji/mcp-servers/jwtAuditor-Mcp"
}
}
}
- Make sure the
cwd
path matches your project directory. - This will launch the server in the correct environment using
uv
.
4. Example mcp.json for MCP Inspector or other clients
If you want to use the MCP Inspector or another tool that requires an mcp.json
config, use:
{
"mcpServers": {
"jwt-auditor": {
"type": "stdio",
"command": "uv",
"args": ["run", "server.py"],
"cwd": "/Users/haji/mcp-servers/jwtAuditor-Mcp"
}
}
}
Security
- All JWT operations are performed locally.
- No tokens or secrets are sent to any external service.
Credits
- Inspired by JWTAuditor
- Built with MCP Python SDK