You'll noticeTier: how much it should matter to you
3Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
ArtifactsArea: what it touches
ImprovementsKind: in v2.1.265,
ImprovementsSection of the release
What
Claude Code has new built-in guidance explaining how to edit "artifact" documents safely when multiple edits might happen. Every time a document is read or written, the response includes a version number. To update the document with update or str_replace, that version must be passed back as if_version. If the document has changed since that version was read, the write is refused and nothing is applied.
Why
This prevents one edit from silently overwriting changes made in between, since a write only succeeds if it's based on the document's current version.
