You'll noticeTier: how much it should matter to you
4Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
API EndpointsArea: what it touches
ImprovementsKind: in v2.1.246,
What probably matters to youSection of the release
What
Claude Code now watches whether prompt caching is actually taking effect. After three turns in a row with 20,000 or more input tokens and essentially no cache being written or read, it logs a warning that a custom endpoint is discarding the cache, which shows up as slower, more expensive turns.
Details
Emits api_prompt_cache_coverage with a cache_coverage_loss outcome plus the consecutive-turn count and token counts.
A one-time confirmation on the same event fires instead when caching is seen working.
The check runs for providers reached through a gateway, and conditionally for the first-party API.
Evidence
sustained uncovered input with a cache breakpoint on the wire through a custom endpoint
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
