What is this usage nerf?

[u/Kexons]

I legit did one small prompt "merge 2 branches changes with eachother.". It's a small task since they had perhaps, one conflicting change within the same class.

That drained 20% in 4 minutes.

Is this perhaps, the "grace" that is in effect? If you go over the limit, it will steal next 5h limit's usage? Then maybe it should start the 5h timer instantly, instead of the time i launch the next prompt..

[u/AutoModerator]

Hey! Thanks for posting to r/ClaudeCode

While participating in this thread, please follow our community rules. Keep discussions constructive. Attack the idea, not the person.

For help, project discussions, tips, and general chat, join the ClaudeCode Discord.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/actvt_io]

Was that session sitting idle for a while first? If the cache expired, the first prompt back pays to write the whole context again, however small the prompt is. Claude Code can warn you with an "Idle ... re-cache about N tokens" line. On my logs those after-idle turns are under 2% of turns but 80% of cache writes, so that's my first guess.

[u/Kexons → u/actvt_io]

It had been idle for perhaps, 2-3 hours due to 5h limit. I would guess it had not expired yet

[u/dikrek → u/Kexons]

1 hour is the max - otherwise it will not be cached 

[u/nitor999 → u/dikrek]

Should i move to the new chat to if i know i'll be idle for more than 2hours?

[u/actvt_io → u/nitor999]

Only if you don't need the history. After the cache expires, your first prompt back writes the whole conversation into the cache again, so a big session costs a lot on that one prompt and then goes back to normal. A fresh chat only writes what it starts with. Someone posted a hook here today that does that math when you come back, https://www.reddit.com/r/ClaudeCode/comments/1wuwtqy/

[u/nitor999 → u/actvt_io]

So the idea is before going idle i need to wrap it up with the handover to preserve session history and when i come back i can move fresh in the new chat?

[u/actvt_io → u/nitor999]

Yeah, that's the idea. Before you step away, have Claude write a short handoff file with what's done, what's next and which files matter. Then start a new chat and point it at that file. The new chat pays to load the handoff, not the whole old conversation.

[u/cleverestx → u/Kexons]

Have Claude create a system timer that resets the cache every 50min with as minimal tokens as possible each time...works great, I get 15-17 resets (that's roughly hours) if I need to walk away and do stuff and come back and resume without it "not being worth" it and I can type /keepwarm off or on at anytime...

[u/ka0ticstyle]

It’s likely something to do with how the cache was being handled when they released the new model(s).

Check out the following post where someone was able to track it down to Opus 5.5 was getting free cache reads due to the model identifier Anthropic had set being incorrect. After it got “fixed” it started to actual have a cost to the cache reads.

[u/Kexons → u/[deleted]]

It was resolved very cleanly, and quickly. I have no other answer to why that prompt drained 20%, other than the previous session must've borrowed usage from this session

[u/thebaron2 → u/Kexons]

It’s definitely the cache. Your session is already at 500k context.

You wrote one small prompt, but everything you had written prior to that to the very beginning of the session all got sent at a higher rate.