An Hour Down Claude Code's Memory Hole

TL;DR: Claude Code ships an auto-memory feature on by default. It eats roughly 47% of every system prompt. One environment variable turns it off, and behavior improves immediately. The story below is what I saw and how I found the switch. Claude Code was acting off this week. Saving memories I didn't ask it to save. Taking verbose detours on simple tasks. Once, it edited a file without reading it first and guessed wrong about the contents. None of that was catastrophic. It was just friction. The