Most reporting artifacts have no chain. The thing a firm actually gets audited on is a spreadsheet, a reconciliation export, or a report builder's PDF, produced by a tool that is not part of this graph. This binder computes the OpenChainGraph §27.4 subject identifier for exactly that case, so a signed preparer, reviewer and approver trail can attach to an artifact we did not compute.
The identifier is SHA-256 over the JCS canonicalisation of exactly three members: tool_ref, inputs_digest and artifact. There is no fourth member. No wall clock, no run identifier and no host or session state enters it, so anyone holding the echoed preimage recomputes the same value offline without ever running the producer. manifest_digest inside tool_ref is the chainless counterpart of the §17 kernel digest: it is what makes the producer tamper-evident, not merely its output.
An attested-artifact subject carries no §18 compute proof and no §16 or §17 re-execution claim. It evidences producer pinning, input binding and content integrity. It never evidences that the producer's arithmetic is correct.
Because no replay was attempted, the exported artifact omits replay_verified entirely rather than setting it false. Omission is the honest encoding, since false would read as a replay that was attempted and disagreed.
A digest binds bytes to a claim between parties who already hold both, which is what makes it useful to a counterparty in a dispute. It is not a claim of regulator acceptance, submittability, or admissibility, and an approval record over this subject evidences that a human acted and nothing more.
This is the value every §27 approval record over this artifact carries as its subject_hash.
Implements the §27.4 non-node gate subject described in the OpenChainGraph specification. The subject identifier it computes is what a separately signed §27 approval record names, and what a §27.6 evidence bundle aggregates the accountability trail against.