The did:oas identifier
Use the actual parser for namespaces, kind variants, and identifiers.
The typical form is did:oas:<namespace>:<kind>:<identifier>. agent:instance is a compound kind and uses another colon-separated component. Identifiers need not be public-key multibase strings; an identifier such as weather-bot is valid syntax.
Use OasDid and EntityKind rather than a fixed-length string split. The parser validates syntax; it does not retrieve a document or authorize an action.
From identifier to trust
Retrieve the document through your configured resolver, validate its structure and proofs, then evaluate the relevant lineage/authority policy. Creating, updating or deactivating a document requires the concrete provider and storage contract. These operations are not generic /v1/dids routes on the standalone server.
See DID parser signatures, kind variants, resolution, and the actual HTTP APIs.