You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
CompactionArea: what it touches
ImprovementsKind: in v2.1.248,
ImprovementsSection of the release
What
Cache markers, which decide how much of a conversation the model can reuse between requests, now step over ephemeral user messages when placing themselves, so short-lived messages do not invalidate the cache.
Details
Ephemeral user messages are treated like system entries during the backwards walk.
The trailing-system optimisation is refused if an ephemeral user message sits in between.
Fork-point pinning is skipped entirely when a top-level cache control is supplied.
Evidence
(fe.type === "user" && fe.ephemeral === !0)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
