agentrust-trace-adapters

agentrust-trace-adapters

Build TRACE Trust Records from evidence another system produced, without fabricating what is not there.

Why this exists

An adapter over someone else's runtime governance product is worth building for one reason: it states, in a form a machine can read, exactly what that evidence is worth next to a hardware-attested record. A record built here carries three signals a consumer can key on without reading prose:

None of the three is a parameter. An adapter that could set them would eventually set them wrong.

If the source separately produces a signed appraisal result, use AppraisalEvidence / appraisal_from_evidence only after verifying that signature. The contract requires a named verifier and appraisal-policy reference. A vendor's bare ALLOW/DENY result is still a policy decision, not an appraisal of the evidence behind that decision.

That argument only holds if the rest of the record is true, which is the harder half.

The failure this package prevents

Before it existed, this repository contained one vendor-to-TRACE adapter. Its output failed TrustRecord validation on seven counts:

model.weights_digest      'sha256:placeholder-no-model'
runtime.platform          'software-simulated'          (not in the enum)
runtime.measurement       'sha384:000...000'
tool_transcript.hash      't1'                          (not a hash at all)
build_provenance.digest   'sha256:placeholder'

Five of those are the same mistake: a required-shaped field with nothing real to put in it, so a placeholder went in. Nothing in CI noticed, because nothing validated the output.

So every constructor here takes bytes, not names of bytes, and raises MissingEvidence rather than degrading:

digest_bytes("policy-v1.2")     # TypeError: hashing a description of bytes is not a digest
digest_bytes(b"")               # MissingEvidence: the digest of nothing is a valid-looking hash of an absence
PolicyEvidence(bundle=b"", enforcement_mode="declared")  # MissingEvidence: needs the policy bundle bytes
build_record(..., workload_digest=None)  # MissingEvidence: nothing truthful to default it to

A record nobody can build is a truthful outcome. A record full of placeholders is not.

Use

from agentrust_trace_adapters import PolicyEvidence, SourceSystem, build_record

record = build_record(
    source=SourceSystem(
        producer="vendor-gateway/2.1",
        source_event_id="evt-7f3a",
    ),
    subject="spiffe://example.org/agent/support-bot",
    model_provider="anthropic",
    model_id="claude-sonnet-4-6",
    # The policy bytes being bound into the evidence. Most control planes do not put
    # the bundle in their telemetry; that is not a reason to hash something else.
    policy=PolicyEvidence(
        bundle=open("policy.cedar", "rb").read(),
        enforcement_mode="declared",
    ),
    data_class="internal",
    workload_digest="sha256:...",   # the image or artifact the producer reports
    jwk=public_jwk,
)
assert record["policy"]["enforcement_mode"] == "declared"

Since 0.2.0, enforcement_mode is required and has no default. In 0.1.1 omitting it emitted "enforce", which claims enforcement the constructor cannot know about, and TRACE spec section 4.3 says "declared" MUST NOT be a default either. Pass "declared" when the policy is bound but nothing here evaluated it, and "enforce", "advisory" or "silent" only when your deployment established that mode. This changes evidence-constructor calls only; runtime enforcement is unchanged.

The "declared" value requires agentrust-trace>=0.9.0; the package dependency floor is raised accordingly.

NVIDIA OpenShell

OpenShellEvidence binds the two policy layers and the complete machine-readable runtime transcript into one Level 0 record:

from agentrust_trace_adapters import OpenShellEvidence, build_openshell_record

evidence = OpenShellEvidence(
    sandbox_id="sbx-123",
    policy_revision="42",
    openshell_policy=open("effective-policy.yaml", "rb").read(),
    acs_manifest=open("agent-control.yaml", "rb").read(),
    ocsf_jsonl=open("openshell-ocsf.jsonl", "rb").read(),
    acs_decisions=tuple(acs_decisions),
    capture_start=1775014138000,
    capture_end=1775014199000,
    capture_complete=True,
    openshell_version="0.0.105",
)
record = build_openshell_record(
    evidence,
    subject="spiffe://example.org/agent/support-bot",
    model_provider="anthropic",
    model_id="claude-sonnet-4-6",
    data_class="internal",
    workload_digest="sha256:...",
    jwk=public_jwk,
)

The adapter refuses incomplete capture, malformed or non-OpenShell OCSF events, missing policy bytes, or a missing policy revision. It does not infer hardware attestation from an OpenShell compute driver.

Signing is not here. It belongs to agentrust_trace.sign, and an adapter that both assembles and signs invites a caller to skip looking at what it assembled.

Two questions worth answering before you write an adapter

Does the producer expose the policy bundle it enforced? If not, you supply it: an operator knows the policy it runs even when its vendor's export does not carry it. If nobody can produce those bytes, the record cannot honestly carry a policy.bundle_hash, and it should not be built.

Does the producer report the artifact it ran? build_provenance.digest is required by the schema and there is nothing truthful to default it to.

If both answers are no, the finding is that the evidence does not support a Trust Record. That is a result, not a blocker to route around.

What runtime.measurement means here

It is a deterministic digest over the identifying inputs (producer, subject, policy bundle hash), not a hardware measurement. The schema requires the field and there is no measurement to put in it; the same shape as the sandbox adapter in agentrust-trace. Two records over the same inputs agree, a changed input is visible, and platform: software-only carries the fact that nothing measured it.

Tests

31 builder tests, one per way a record could validate and still be untrue, including two that parse the built record with the real TrustRecord model. That last pair is what the previous adapter did not have.

Licence

Apache-2.0.

Candidate OpenShell bundle verifier (since 0.1.1)

agentrust_trace_adapters.openshell_bundle.verify_bundle ships from 0.1.1. It verifies a proposed signed OpenShell evidence bundle, described with its synthetic acceptance cases in the producer contract. The contract is development work for NVIDIA/OpenShell#2745 and does not exist upstream yet, so no live exporter compatibility or hardware assurance is claimed. The OpenShell transcript adapter is unaffected.