Prompt-cache-break diagnostics now capture a structured shape of the first message per cache source, covering block kinds, lengths, hashes, named sections, and worker-tool counts. When a cache break is attributed to the first message, this shape is diffed against the previous call, adding msg0Sections, msg0ChangedSections, msg0AddedSections/RemovedSections, and msg0ChangedBlocks to the break-diagnosis telemetry.
New prompt-cache-break diagnostics: msg0 shape tracking
New internal diagnostics track the first message's shape to diagnose cache breaks.
Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Prompt CachingArea: what it touches
Internal ChangesKind: in v2.1.261,
Internal ChangesSection of the release