Keep Claude Code’s cache warm. On Fable 5.1, a 1-hour cache write costs 80x a read.

On Fable 5.1, keeping Claude Code's cache warm is crucial, as a 1-hour cache write costs 80 times more than a read. Evidence from a dev community shows a cache write estimate of $6.61, with a reported cost of $6.28 after resending. A background agent later read 156,886 cached tokens 62 minutes after the previous response, indicating the cache refresh was successful despite exceeding the one-hour expiry. This highlights the significant cost difference between cache writes and reads.