Trace deduplication makes source-image retention a reader contract

When an AI trace replaces its private image copy with a reference to a canonical Supabase object, source-image retention becomes part of the trace reader contract. Before deleting the canonical object, inventory active trace references and decide whether expired traces should lose image access or whether another retention policy requires independent storage. Deleting only duplicate objects does not erase all evidence, while deleting the canonical object can break evaluation and support readers that previously had independent copies. This applies where deduplication actually suppresses writes; a shared digest alone does not establish ownership or dependency.

Applies when: Image deduplication and retention cleanup share canonical storage. Keywords: Supabase storage image retention deletion deduplication traces evaluation references