pexpect-mcp
An MCP (Model Context Protocol) server that provides remote pexpect session control for debugging and process interaction.
Overview
This MCP server enables AI assistants to execute Python code with pexpect functionality, allowing for interactive debugging sessions with tools like LLDB, GDB, and other command-line utilities that require programmatic interaction.
In some sense this is less of a pexpect MCP as one that is just maintaining a stateful Python session.
Installation
uv tool install git+https://github.com/mitsuhiko/pexpect-mcp
Usage
As an MCP Server
Add to your Claude Code configuration:
{
"mcpServers": {
"pexpect": {
"command": "pexpect-mcp"
}
}
}
Tool Usage
The server provides a single tool: pexpect_tool
Parameters:
code(string): Python code to execute with pexpect supporttimeout(optional int): Timeout in seconds (default: 30)
Example Usage:
# Start a debugging session
child = pexpect.spawn('lldb ./my-program')
child.expect('(lldb)')
# Run the program
child.sendline('run')
child.expect('(lldb)')
print(child.before.decode())
# Get backtrace
child.sendline('bt')
child.expect('(lldb)')
print(child.before.decode())
Demo
The repository includes a demo with a buggy C program (demo-buggy.c) that can
be debugged using LLDB through the pexpect interface. This demonstrates the
server's capability for interactive debugging sessions.
The program `./demo-buggy` crashes when executed. Use LLDB to:
- Start the program under the debugger
- Identify where and why it crashes
- Examine variables, memory, and call stack
- Report the root cause of the crash
Requirements
- Python ≥ 3.12.1
- pexpect ≥ 4.9.0
- mcp ≥ 1.13.0
License
See LICENSE file for details.