What
When a session transcript is too big to read in one go, Claude Code now walks it forward record by record and stitches the pieces back together, so a large history loads instead of erroring. This applies only when the newer storage backend (storage v5) is in use.
Details
- A failed whole-file read, or a backend refusal reporting
telemetryCode"EFBIG", triggers the paged read, which itself has a byte cap; exceeding it throws an error carrying{ code: "EFBIG" }. - A cursor that fails to advance throws
loadTranscriptFile: the record cursor did not advance; a successful paged read logs record and byte counts. - Tail reads of a session file fall back to a backward record page when the tail read is unsupported, and the tail result gains a
cutflag meaning the content was truncated. - Which flag selects the storage v5 backend is not settled by this build's code.
Evidence
loadTranscriptFile: the paged transcript is too large
Strings lifted out of the shipped bundle, so the claim above can be checked against them.