From my experience Claude Code is not that bad with Common Lisp and can do REPL-style development. I've been using this MCP server (an older version with some tweaks): https://github.com/cl-ai-project/cl-mcp (even though I'd probably prefer some MCP-to-swank adapter if it existed) And this MCP server works quite well for Emacs https://github.com/rhblind/emacs-mcp-server

There are some issues of course. Sometimes, Claude Code gets into "parenthesis counting loop" which is somewhat hilarious, but luckily this doesn't really happen too often for me. In the worst case I fix the problematic fragment myself and then let it continue. But overall I'd say Claude Code is not bad at all with Lisps