Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
ElsewhereArea: what it touches
Internal ChangesKind: in v2.1.302,
Internal ChangesSection of the release
What
Claude Code saves time by reusing text it has already sent to the model, which is called prompt caching. The key that decides whether a tool's text can be reused now includes one more piece of information: whether an agent's 'when to use' description is empty or filled in.
Why
In practice, cached tool text is now kept separate for agents with and without that description.
