Refactory splits monolith source files into clean modules. It uses an LLM to decide which functions group together, then a deterministic engine handles the routine extractions — the straightforward 80% that would waste AI time and tokens. The LLM still handles complex edge cases where judgment matters. JS and Python extractors are free and open source (AGPL). Tested against 15 monoliths, 32,000+ lines. Works with Claude Code, Cursor, Windsurf, or any MCP client. Also runs as a CLI.