Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
Prompt CacheArea: what it touches
Internal ChangesKind: in v2.1.319,
Internal ChangesSection of the release
What
The prompt cache lets the model reuse work from earlier requests when the start of a request has not changed. Claude Code keeps track of when that reuse breaks. The tracker now:
records a fingerprint (a hash) for each setting separately
can look at its current state without changing it
keeps the fingerprint of the tools list
It no longer compares the system prompt fingerprint it had stored.
Why
This is internal reporting about cache use, not a change to how the cache works.
