How to use CSTALE: serve slightly-old, refresh behind it
CSTALE returns a cached answer even past its TTL, flagged as stale, so an expired entry is a snappy answer plus a refresh signal, not a cold miss.
Hard expiry turns a one-second-old answer into a full model call. CSTALE hands back the cached value with a stale flag, and you decide whether to use it as-is or refresh.
> CSTALE "today's status page summary" TENANT acme
1) "All systems operational."
2) "stale" # past TTL -> refresh in the background if it mattersIgnore the flag for tolerant answers; treat it as a trigger to recompute for prices and balances.