assay

Object-reference traversal

Content addressing proves byte integrity, not that every hash-looking string is a dependency. Assay follows explicit paths according to the referring artifact’s role. An input/output artifact that happens to contain schema_version, $ref, or fields named output_ref is still data, not another governed record.

Artifact	Followed fields
Study snapshot	Task and three schema refs, pricing catalog, subject digest/payload refs, realization digest/artifact refs, evaluator basis/payload-schema refs
Execution plan	Snapshot, declaration hashes, execution conditions, cell realization refs
Run manifest	Plan and execution/evaluation/operating record maps
Execution outcome	Plan, input, output, trace, coordinate realization
Evaluation failure	Plan and trace
PAA evidence	Sources, boundary input/output, worker configuration, payload plan/base-subject/detail refs
PAA operating record	Sources and worker configuration
Report configuration	Manifests and evaluation records
Report	Configuration, manifests, evaluation/operating records, comparison common-subject objects

Referenced objects retain their field-assigned role. The same bytes may be visited in multiple roles; traversal caches distinguish them. Cycles are bounded by visited (content address, role) pairs. Ordinary data strings are not visited.

Extension data

Any JSON object in extension data may contain assay_object_refs, an array of valid content addresses. This is a reserved key, not a suffix-based heuristic:

{
  "description": "sha256: is ordinary text here",
  "assay_object_refs": [
    "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
  ]
}

These dependencies must exist, are hash-checked, and are included in export. Their JSON dependencies use the same convention; non-JSON content is a leaf. Parseable JSON bytes must match Assay’s canonical encoding before their references are traversed or cached. Duplicate keys, nonfinite numbers, and noncanonical encodings are rejected, not treated as opaque leaves. This applies even to JSON objects with no references. Opaque non-JSON artifacts remain valid leaves.

A custom field named artifact_ref alone is not a dependency declaration. Producers must include that address in assay_object_refs as well. This replaces the previous implicit traversal of arbitrary sha256: strings; re-export existing runs if their extension data did not depend on implicit edges, otherwise rematerialize the affected study with explicit dependencies and a new authorized plan.

Schemas and record validation

Pinned schemas have their own traversal role. Content-addressed $ref, $dynamicRef, and $recursiveRef values in schema locations are dependencies (fragments address locations within that object). Schema applicators are visited; instance-valued default, examples, const, and enum are not. URL schema refs are resolved only through the pinned local registry, never fetched remotely. Schema validation and resource resolution both default to draft-07 when $schema is absent; explicit supported dialects are honored.

Traversal is separate from semantic validation. The verifier additionally checks canonical JSON for known execution artifacts and evaluator details, valid source addresses, required authoritative evidence lineage, and exact plan coordinates. The closure does not prove that an evaluator scored those bytes or attest producer identity; it verifies consistency of the supplied records and plan.