Evidence

What every call leaves behind: the Problem it answers when it fails, and the call record that is kept.

Every call answers with a result or a Problem, and leaves a Call record that is kept.

ProvenanceWho asserted a fact and how, on four axes; an ingested record that cannot be stamped is rejected, never defaulted.

Errors

Every Problem an API answers a Customer with, each with a stable code and a page of its own.