Store a fact under scope+key. Writing an existing key appends a new version instead of overwriting, so nothing is ever silently lost.

Read the current version of a key (scope+key), or search current records by scope prefix, tag, free text and minimum confidence.

Every version of one key, oldest first: who wrote it, when, with what confidence, and the hash chain that ties the versions together.

Write a handoff packet: what was done, what is left, what is still unclear, and which exact record versions the next agent must read. With no refs given, everything this session touched is pinned.

Claim the oldest open packet addressed to this agent (or a specific one by id) and get back the packet together with the pinned records. Refs whose version has moved on are reported as stale rather than silently swapped for the newer version.

Close the loop: report success or failure against the records that drove the decision. Their confidence moves accordingly, and the before/after values are kept as an audit trail. Pass handoff_id to close the packet in the same call.

Counts per agent and scope, average confidence, handoff states, and an integrity check of the hash chain.