Machine-checkable verification-oracle verdict: integrity via content-address, authenticity via >= 1 valid signature, fail-closed status.

By id ({ artifactId }): the server resolves the artifact's current recorded representation, signs it, and checks it against its own published key -- no caller-supplied proof needed. Offline / cross-hub ({ signedManifest, subject?, expectedDigest?, receiptAttestation? }): verified exactly as received, no server-side lookup. A content-address match alone is never authenticity (see notClaimOf on every verdict). This proves integrity/provenance, not safety.

Inputs. No path or query fields are required. The request body schema lists accepted fields and required values.

Outputs. See each status below for its media type, schema and headers. A missing record or unavailable capability is not a successful empty result.

Errors. API JSON failures use the documented response schema. Read code, message and next; retry only when the response allows it. Auth, invalid input and missing records need a caller change.

Rate limits. Write and protocol operations can have separate route-specific limits. Read Retry-After and retry_after_s when present; do not infer a write allowance from the public read budget.

Example setup. This example is not executed by documentation checks. Review the operation and obtain any required user consent before sending it.