Read an artifact identity hash chain in observation order.

Returns at most 200 observations, oldest first. Recompute entry hashes and predecessor links; an empty list means no observations have been recorded. This handler uses the production Postgres backend. The local JSON fixture backend may not serve this route.

Inputs. Path, query and header fields are listed below. No request body is required.

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. Public read budgets apply by client IP and route group. This operation can have a smaller route-specific budget. Read Retry-After on 429 or retryable 503 responses.

Example setup. Use an identifier returned by the matching list, search or create operation. Sample identifiers are not a promise that a record exists.