You'll noticeTier: how much it should matter to you
4Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
Status OutputArea: what it touches
New FeaturesKind: in v2.1.251,
What probably matters to youSection of the release
What
Each turn's status and debug payload now includes a prompt-cache block, and there is a one-line summary of the main conversation's cache: whether it is warm, how many requests and misses there have been, the hit ratio, and how many rebuilds are expected.
Details
Fields recorded: warm, caching_observed, ttl, expires_at, requests, misses, expected_rebuilds, hit_ratio, cache_write_tokens, and miss_recache_tokens, the tokens that would need recaching if the cache went cold.
Sits alongside the existing cost and context window fields.
Computed only once there has been at least one request; with zero requests the block is empty.
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeAdded a per-session prompt-cache line to /cost (hit ratio, misses, tokens re-cached, warm/cold) and a matching prompt_cache object for…
