The save hook and precompact hook were telling the agent to write
diary entries, add drawers, and add KG triples IN THE CHAT WINDOW.
Every line written stays in conversation history and retransmits on
every subsequent turn — ~$1/session in wasted tokens.
Fix: hooks now say "saved in background, no action needed" and use
decision: allow instead of block. The agent continues working without
interruption. All filing happens via the background pipeline.
Also updated hooks README with:
- Known limitation: hooks require session restart after install
- Updated cost section: zero tokens, background-only
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>