I Built a Tool That Forces AI Coding Agents to Keep Documentation in Sync

Second commit passes because docs are now staged alongside code. The hook doesn't need to call any AI — it just checks whether the right files are included. The self-invocation guard is critical: if the hook tried to spawn Claude Code as a subprocess while Claude Code is already running, you'd get a deadlock. By detecting the CLAUDECODE env var and skipping all engines, the hook avoids this entirely. API Auto-Fix for Human Commits When you commit from the terminal (no CLAUDECODE env var), the hook calls the Anthropic API directly to update your docs: "autoFix" : { "hook" : { "mode" : "blocking" }, "narrative" : { "engine" : "api" , "model" : "claude-sonnet-4-20250514" } } It reads your staged source files, reads the current ARCHITECTURE.md , sends both to the API, and writes back the updated sections. About 20 seconds and ~$0.10 per commit. The hook stages the updated docs and the commit proceeds without you doing anything. If the API is down or your key is missing, the hook degrades t