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Changelog

All notable changes to the TRACE specification will be documented here.

Format: Semantic Versioning. Spec versions follow MAJOR.MINOR.PATCH: - MAJOR: breaking changes to wire format or required Trust Record fields - MINOR: new optional fields, new platform profiles, new conformance levels - PATCH: editorial fixes, clarifications, non-normative additions

[Unreleased]

Added

  • verify_record(..., revocation=...) enforces key revocation at verification time (#76). §3.2.1 has always required that "Verifiers MUST consult current revocation status at verification time", but verify_record() checked only signature and freshness, so a record signed by a revoked or compromised key kept verifying. The new revocation parameter accepts either a container of revoked key identifiers or a callable performing a live CRL, status-endpoint, or SCITT lookup. A listed key is rejected, and a store that cannot answer is also rejected: an unavailable revocation source is not evidence that a key is unrevoked.

Keys are identified by RFC 7638 JWK Thumbprint or kid. The check reads the trusted key rather than record["cnf"]["jwk"], which is attacker-controlled until the signature verifies.

Additive and backward compatible: revocation defaults to None, which leaves verification purely offline and unchanged. That mode cannot prove non-revocation, now stated in LIMITATIONS.md and docs/verification.md. No normative text, schema, or record field changed.

  • jwk_thumbprint(jwk): RFC 7638 JWK Thumbprint (RFC 8037 §2 for OKP), exported so callers can key a revocation list on the same identifier the verifier derives.

[0.5.1] — 2026-07-28

Fixed

  • transparency is optional below Level 2. The model required a non-empty URI on every record, which was stricter than both schema/trace-claim.json (required, no minLength) and the conformance suite, which runs TR-ANC at Level 2 only. A Level 0 or Level 1 record is not anchored, so it has no receipt to name, and that state was unrepresentable. None now means unanchored; an empty string stays rejected, since "" is not a URI and a field that looks populated but resolves to nothing is worse in a trust record than an absent one.

Changed

  • BREAKING: TRACE v0.2 changes the EAT profile URI to tag:agentrust-io.com,2026:trace-v0.2 (was tag:agentrust.io,2026:trace-v0.1). agentrust.io was never a domain this project controlled; it resolves to third-party parked addresses. RFC 4151 permits a tag URI only where the minting authority controlled the named domain on the stated date, so the v0.1 identifier was invalid rather than merely misspelled: it asserted authority over a name someone else could stand up a conflicting definition at.

Cutover, not coexistence. A v0.2 verifier requires the new URI and rejects the old one; it does not accept both. Dual acceptance would keep the invalid identifier live indefinitely, which is the thing being fixed. Records already issued under v0.1 stay verifiable against spec/trace-v0.1.md and the published agentrust-trace 0.4.x releases, which remain on PyPI. They are v0.1 records and are read as such.

Nothing else in the record format changed. No field was added, removed, or re-typed, so migration for a producer is the profile string and a dependency bump.

Moved together: spec/trace-v0.2.md (new, with a "Changes from v0.1" section), spec/trace-v0.1.md (retained, marked superseded), the root schema/trace-claim.json const, the packaged agentrust_trace/schema/trace-v0.2.json, the eat_profile Literal in models.py, the AGT adapter, validate.py's schema resource, the four platform example records, and the docs.

  • Other agentrust.io URLs moved to agentrust-io.com: the registry and verifier hosts in the AGT adapter and the schema $id.

[0.4.0]

Added

  • azure-cvm-sev-snp platform — Azure confidential VMs run AMD SEV-SNP behind a Hyper-V paravisor: the SNP report is read from the vTPM (the guest does not control REPORT_DATA), so the runtime binding rides a vTPM AK-signed quote rather than the SNP report_data. Given its own runtime.platform value (distinct from amd-sev-snp) so a consumer keying on runtime.platform knows the root of trust is vTPM-rooted, not direct-silicon. Added to the RuntimeInfo model and the JSON schema enum. Hardware-validated on a live Azure SEV-SNP VM via cMCP.

  • delegation (optional object): the A2A profile delegation-link block, carrying parent_record_hash (digest of the parent hop's Trust Record) and credential_id (the delegation credential this hop acted under). A chain of records linked this way forms an offline-verifiable delegation DAG. Backward-compatible: existing records without delegation remain valid. This is a MINOR (additive) change and the foundation of the forthcoming A2A profile; A2A is now stable at v1.x, clearing the prior blocker.

[0.3.0] — 2026-06-30

Security

  • verify_record now requires an explicit trusted key. Self-verification from the embedded cnf.jwk is no longer the default; use allow_embedded_key=True to opt in.
  • Verification enforces freshness (iat / max_age_seconds, default 24h) and an optional expected_nonce. JWK kty / crv are validated.

Breaking

  • BREAKING: Canonicalization is now RFC 8785 (JCS). Trust records are NOT cross-verifiable with 0.2.0 (the prior json.dumps canonicalization was non-conformant).

[0.1.0] — 2026-06-23

Initial public draft. Announced at Confidential Computing Summit, San Francisco.

Specification

  • Trust Record logical schema (§3.1): subject, model, runtime, policy, data_class, tool_transcript, build_provenance, appraisal, transparency, cnf
  • Wire format (§3.2): EAT/JWT and CBOR-COSE envelopes; profile URI tag:agentrust.io,2026:trace-v0.1
  • Signing and key management (§3.2.1): ES256/ES384/EdDSA; four-layer key hierarchy; hash agility; revocation
  • Verification protocol (§3.3): five-step offline verification, no issuer callback
  • Standards composition (§4): RATS/EAT, SLSA, SPIFFE, SCITT, EAR, MCP, A2A, AIBOM, C2PA
  • Hardware roots (§4.2): NVIDIA H100/Blackwell, Intel TDX, AMD SEV-SNP, Azure MAA, GCP Confidential Space, AWS Nitro
  • Reference implementation (§5): cMCP Phase 1–3 roadmap

Schema

  • schema/trace-claim.json: JSON Schema (draft/2020-12) for Trust Record validation

Examples

  • examples/amd-sev-snp.json: AMD SEV-SNP Trust Record
  • examples/intel-tdx.json: Intel TDX Trust Record
  • examples/nvidia-h100.json: NVIDIA H100 Confidential Computing Trust Record

Open questions

Seven open questions requiring community input before v0.2 are documented in §7 of the spec.

[0.2.0] — TBD

Specification

  • Extend subject field to accept DID URIs (any did: method) in addition to SPIFFE SVIDs. Previously ^spiffe:// only; now ^(spiffe://|did:). Additive, backward-compatible. DID-native runtimes (e.g. AGT did:mesh: identities) no longer require a parallel SPIFFE identity. Closes: microsoft/agent-governance-toolkit ADR-0032, agentrust-io/trace-spec#35.

Schema

  • schema/trace-claim.json: subject pattern updated to ^(spiffe://|did:), description updated.

Reference Implementation

  • TrustRecord.subject pattern updated to r"^(spiffe://|did:)".

Upcoming

See ROADMAP.md for planned changes in v0.2 and v1.0.