OCEL 2.1

Object-Centric Event Log, the open standard for recording events together with the business objects they touch — the format process-mining and audit tooling consumes directly. Ledgerbook emits OCEL 2.1 and accepts OCEL 2.0 or 2.1 inbound.

Canonical definition from the Ledgerbook glossary. Definitions are the product vocabulary — the same terms the API and MCP tools use.