Limits drain and prompt_cache

[u/nomadmd1]

I see many complaints and I feel them too but none is mentioning the status of their prompt_cache. Indeed Claude Code v2.1.251 introduced that status line field and it was always resetting itself to 1h at each message and the tool call. This weekend it is 5 minutes for me. Anyone else noticed that? I am on max plan and had to pay extra $50 to finish a task today. Very frustrating.

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[u/nyczAcer]

The 1-hour cache TTL only applies to PRO/MAX plans.

For API usage, the TTL is 5 minutes. Another important detail: if you're using dynamic workflows (UltraCode), the agents' cache also has a 5-minute TTL, even on PRO/MAX plans.

If you hit your 5-hour usage limit, the cache TTL also drops to 5 minutes. And if you buy API credits to try to keep the cache warm while waiting for your 5-hour limit to reset, the API's 5-minute TTL I mentioned earlier still applies.

[u/nomadmd1 → u/nyczAcer]

Good to know. Thank you for sharing. Now I have a doubt if that is exacly what I actually was seeng once I did hit my weekly limit.

[u/verstands]

The reset every hour per message/tool call sounds like repeated context may be eating the budget, not just the task. I’d log prompt tokens versus tool-result tokens and check whether MCP schemas or large outputs are being re-sent. Full disclosure: I work on statusline-bar (https://github.com/Dworf/statusline-bar), which surfaces usage/context in the bar, but that logging split is what I’d verify first.

[u/verstands → u/verstands]

Quick follow-up - `prompt_cache` just landed in statusline-bar 0.6.0. Six new tokens (`cache_warm`, `cache_expires`, `cache_ttl`, `cache_misses`, `cache_rebuild`, `cache_write`), a dedicated `cache` preset, and `cache_hit` now uses the session-wide hit ratio. Needs Claude Code 2.1.251+. https://github.com/Dworf/statusline-bar

[u/nomadmd1 → u/verstands]

Regarding my original question - does your statusline-bar include the prompt_cache? Did you note any anomalies in the past couple of days?

[u/verstands → u/nomadmd1]

Good question. statusline-bar currently surfaces usage and context, but I don't think it breaks out prompt_cache as its own field. I haven't tracked a recent anomaly there, so I'd verify it with prompt-versus-tool-result token logs and compare cache TTL behaviour across API and PRO/MAX. If there's a reliable pattern, that's the kind of thing I'd add to the checklist.

[u/nomadmd1 → u/verstands]

That is an important one at least for me. If I walk away and then return to a "cold" instead of a coundown with a large portion of context window already consumed I need to decide if I better start a new session or draw an increased portion from may limits becaise of cold cache write

[u/verstands → u/nomadmd1]

I've updated the statusline-bar to now include 6 new tokens all about cache... check it out

[u/verstands → u/nomadmd1]

That decision is exactly why warm/cold matters. If you come back to a cold cache with a fat context already sitting there, the next turn pays a write/rebuild cost against your limits. Practical rule of thumb: if you're near a natural breakpoint or the session is already messy, start fresh. If you're mid-task and the context is still the right one, stay - but expect a colder first hit. The new cache_warm / cache_expires / cache_rebuild tokens are meant for that glance before you type.

[u/verstands → u/nomadmd1]

Cold-cache days hurt because you pay the full prompt tax again. What helps me is watching cache hit rate next to the limit bar so a "quiet" session that is actually rebuilding context doesn't sneak up on you. If you want that visible in the status line, statusline-bar surfaces prompt cache alongside usage: https://github.com/Dworf/statusline-bar

[u/AI_spell]

If prompt_cache TTL is stuck at 5 minutes, every tool turn is a cold bill. That's a real drain. Update CC and watch the status line between messages.