# Evidence

URL: /evidence · Id: `page:/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](/evidence/errors), and leaves a [Call record](/evidence/call-record) that is kept.

- [Provenance](/evidence/provenance): Who asserted a fact and how, on four axes; an ingested record that cannot be stamped is rejected, never defaulted.