https://github.com/jacobsparts/agentlib

See CodeAgent or subrepl.py if you're just interested in the REPL orchestration. I also have a Python REPL MCP server that works with CC. It isn't published, but I could share it by request.

My favorite part of code agent is the /repl command. I can drop into the REPL mid session and load modules, poke around with APIs and data, or just point Claude in the right direction. Sometimes a snippet of code is worth 1000 words.