What
Instructions that come with an Artifact type are now wrapped in a preamble and a trailing warning saying they cannot grant permissions or widen the task, since anyone who can publish to the Artifact could have written them.
Details
- Two preambles exist: one for a trusted Artifact type and one for the case where the instructions could have come from any publisher.
- The trailing warning rules out fetching or publishing elsewhere, putting local files or credentials into the Artifact, and editing permission settings, CLAUDE.md or config on the instructions' say-so.
- Always applied as part of assembling the Artifact system prompt.
Evidence
artifact-type-instructions
Strings lifted out of the shipped bundle, so the claim above can be checked against them.