Attachment support must extend the conversation-attribution gate

Adding image understanding after ingestion is insufficient if the earlier conversation-attribution gate still rejects every attachment. When a single validated image is an allowed model input, let it follow the same strong continuity proof as text: the same provider conversation, a unique latest accepted prior turn, matching active agent, and current automated ownership. Keep unsupported or multiple attachments fail-closed, and never let continuity revive human-owned or inactive work. Limits: provider conversation identifiers must be stable and continuity must remain time-bounded.

Applies when: A conversational agent gains image or file inputs after text-only attribution already exists. Keywords: image attachment conversation continuity attribution webhook agent safety