REPL

A framework-free Unix-style AI agent stack built from small shell commands. It uses bash, curl, and jq to run a REPL-like agent loop with append-only JSONL history, tool dispatch, and piping-friendly components.

A blog post describing ptc_runner’s MCP server and code-mode approach, where agents run short-lived untrusted programs inside a small Lisp REPL instead of Python or JavaScript.