Chat attachments don't guarantee delivery

Claude Code and agents

Symptom

A file the agent sent as a chat attachment never reached the human. Twice (an extension zip, a design-mockup HTML).

Rule (hardened)

Every deliverable = a committed repo path + a PR link. Chat attachments are auxiliary, not trusted.
Binaries (zips, images, anything not in the repo) = Releases (tags) or artifacts → delivered as a URL
Mandatory phrase in the report: "Where to look: PR#\<n\> · \<repo file path\>". Without it, treat it as undelivered.