I'm finding that unexpected cache rewrites cost me huge.
I have 1h cache TTL set, and do nothing to cause rewrite (response in time, no model/effort/tool changes).
At 400K tokens in, I'll write a message, and /usage shows only a small increase in cache write. On the next message, cache writes shows 800K, and by the end, I often hit 2M cache writes with no explanation.
This seems to happen when: using /btw, asking it to review code, other random times. Anyone know what's going on?
To not answer your question, I have a claude stop hook that my status line uses to tell me how close my cache is to expiring https://pastebin.com/JLXUG16Q
_entirely_ vibecoded don't @ me.
You may be running into a "known" bug with Claude Code: https://github.com/anthropics/claude-code/issues/63930
This happens all the time and drives me bananas.
It seems to be regular file edits rather than parallel tool calls.
I'm sitting on 1.6m cache write even now with 468k in /context. It drives my session costs above $100 regularly.
Can someone from Anthropic look into this?
I have long suspected but not confirmed that /btw uses a lower tier model like Haiku.
Depending on how you're triggering reviews, you may be using a sub-agent?
it does not use haiku. you can just ask Claude (possibly not fable BC of cyber) to reverse engineer the obfuscated JS.
I don't use sub-agents, only the normal linear message-response flow.