Under the hoodTier: how much it should matter to you
1Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
CachingArea: what it touches
Internal ChangesKind: in v2.1.248,
Internal ChangesSection of the release
What
The logic that lists why the prompt cache was invalidated (model, system prompt, tools, betas, effort and so on) moved into a separate function. Wording and telemetry fields are unchanged.
Evidence
defer_loading presence flipped (deferred-tool hint section, inc-5316)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
