chore(release): 0.5.1

CHANGELOG.md

@@ -11,6 +11,12 @@ Format: [Semantic Versioning](https://semver.org/). Spec versions follow `MAJOR.
 
 ## [Unreleased]
 
+## [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.

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "agentrust-trace"
-version = "0.5.0"
+version = "0.5.1"
 description = "TRACE v0.1 — hardware-attested governance records for AI agents"
 readme = "README.md"
 license = { text = "Apache-2.0" }