User artifacts are never rewritten, but a secret pattern in a version marks
the artifact restricted and audits the reason (review a2-C, SO-12).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RNPhwu2bsaRNg3DETSAZoM
Immutable content-addressed artifact versions with If-Match, lineage that must
resolve under the caller, unified diffs, promotion; sources/passages/citations
with server-side hashing and dedupe, citation integrity checks and revisioned
research notebooks. Cross-tenant access is 404 and audited.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RNPhwu2bsaRNg3DETSAZoM
