ReqManagedAgents.Artifacts store over the Anthropic Files API, scoped to one session. list uses the session-scoped file listing (the only way to discover server-minted file ids for files the agent wrote); fetch/delete act on the newest record when a name appears more than once (re-runs accumulate); put uploads and attaches at opts[:mount_path] (default "/data/<name>").

The default mount path is built as "/data/" <> name with no sanitization — callers passing untrusted names must validate them (path traversal, e.g. "../x", is forwarded verbatim).