01 Long sessions re-reading their own history
Session length- Looks for
- A session past ~25 turns where cache reads are over 70% of its cost.
- Why it costs
- Total cost grows with roughly the square of session length — each turn re-sends everything before it. A 700-turn session can spend more re-reading itself than on all its actual output combined.
- Fix
- /clear between unrelated tasks. /compact when one thread genuinely needs to continue. Both reset the quadratic. The instinct to keep one long session going so Claude remembers is the single most expensive habit in Claude Code.