MCP Debugger

An Model Context Protocol (MCP) server that provides debugging capabilities for Python, C, C++, Rust, Swift, and more through the Debug Adapter Protocol (DAP).

• Get breakpoints, step-by-step evaluation, and segfault stack traces.
• Read program stdout/stderr in pages (lines: 0-100, etc...) without flooding the context window.
• Programs run async, debug multiple applications at once.

Installation

Cursor:

Claude Code:

claude mcp add --transport stdio Debugger -- npx -y mcp-debugger-dap@latest

Manual configuration:

"Debugger": {
  "command": "npx",
  "args": ["-y", "mcp-debugger-dap@latest"]
}

Supported debuggers

mcp-debugger-dap supports either Python (debugpy) or LLDB supported languages (tested: C, C++, Rust, Swift). Probably more such as Objective-C, Zig, etc... are supported through LLDB.

Python (debugpy)

Python 3 and pip must be installed.

The debugpy wheel is automatically downloaded to ~/.mcp-debugger.

LLDB

LLDB support requires a recent binary of lldb-dap.

For macOS users: On macOS Sequoia+ I confirmed tested, before this YMMV, comes included with XCode Command Line Tools.

For Linux users: I recommend the Helix editor guide to installing lldb-dap.

Demo

The demo/ directory contains example scripts demonstrating race conditions and other bugs that can be debugged using this MCP server.

cd demo
# Use Claude Code or another MCP client to debug:
# "Let's use the debugger to find the race condition in order_processor.py"

References

• Debug Adapter Protocol Specification
• Model Context Protocol
• debugpy Documentation
• LLDB Documentation