Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Prompt CacheArea: what it touches
Internal ChangesKind: in v2.1.286,
Internal ChangesSection of the release
What
Claude Code estimates when its prompt cache has probably expired and what rebuilding it would cost. The prompt cache holds the start of your conversation on the server so it does not need to be reprocessed. That estimate is behind prompt_cache_likely_expired and the estimated cache write cost.
It used to depend only on the model and the size of the context. It now also uses the usage figures from the last response, or from saved session details. Claude Code also records when the main conversation's cache was last renewed.
Why
The cache-expired signal and the estimated cost may now match what actually happened more closely.
How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtHow the usage figures change the estimated cache lifetime is not known.
