You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
ElsewhereArea: what it touches
Bug FixesKind: in v2.1.267,
Bug FixesSection of the release
What
Tool calls whose arguments include a key beginning with __artifact are now denied unless the tool is recognized as one that legitimately mints such keys, with the message "Nothing was done. The arguments carry a key that only Claude Code sets."
This relies on a new mintsArtifactKeys() capability check, which is also used to suppress certain artifact-related event logging for contexts that mint their own artifact keys.
Why
This prevents a model or malicious input from spoofing internal artifact bookkeeping keys that only Claude Code itself is meant to set.
