You'll noticeTier: how much it should matter to you
4Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
File ToolsArea: what it touches
New FeaturesKind: in v2.1.251,
What probably matters to youSection of the release
What
When a write is applied with a recorded content hash, Claude Code now re-hashes the file on disk first and refuses the write if the contents no longer match, so an edit you approved cannot silently clobber a change made in the meantime.
Details
The internal write path takes a baseHash argument; the check runs whenever a caller supplies one.
On mismatch it throws instead of writing, reporting that the file changed since the edit was previewed.
Evidence
file changed since the edit was previewed
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
