diff --git a/.github/workflows/anchor-corpus.yml b/.github/workflows/anchor-corpus.yml
new file mode 100644
index 00000000..750832c6
--- /dev/null
+++ b/.github/workflows/anchor-corpus.yml
@@ -0,0 +1,59 @@
+name: Anchor corpus
+
+# Runs this repository's TR-ANC-002 over an external registry anchor corpus
+# pinned by commit and SHA-256 in conformance/interop/trace-anchor/pin.json.
+# The corpus is read as data; nothing from it is installed or executed. A pin
+# bump is a reviewed change to pin.json, never a floating reference.
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - "conformance/src/trace_tests/modules/tr_anc.py"
+      - "conformance/src/trace_tests/inclusion.py"
+      - "conformance/interop/trace-anchor/**"
+      - "spec/registry-anchor-v1.md"
+      - ".github/workflows/anchor-corpus.yml"
+  pull_request:
+    branches: [main]
+    paths:
+      - "conformance/src/trace_tests/modules/tr_anc.py"
+      - "conformance/src/trace_tests/inclusion.py"
+      - "conformance/interop/trace-anchor/**"
+      - "spec/registry-anchor-v1.md"
+      - ".github/workflows/anchor-corpus.yml"
+  schedule:
+    - cron: "17 6 * * 1"
+  workflow_dispatch:
+
+env:
+  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: "true"
+
+permissions:
+  contents: read
+
+jobs:
+  grade:
+    name: TR-ANC-002 against the pinned anchor corpus
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: conformance
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97 # v5.3.0
+        with:
+          python-version: "3.12"
+      - name: Install the suite
+        run: |
+          pip install --require-hashes -r requirements/test.txt
+          pip install --no-deps -e .
+      - name: Grade
+        run: python interop/trace-anchor/grade.py --report build/anchor-corpus.json
+      - name: Upload the report
+        if: always()
+        uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
+        with:
+          name: anchor-corpus-report
+          path: conformance/build/anchor-corpus.json
+          if-no-files-found: ignore
diff --git a/conformance/docs/modules/tr-anc.md b/conformance/docs/modules/tr-anc.md
index d0de06ad..3ed01949 100644
--- a/conformance/docs/modules/tr-anc.md
+++ b/conformance/docs/modules/tr-anc.md
@@ -15,3 +15,7 @@ Checks that the record was entered in a public, append-only log, so it cannot be
 |---------|-------------|---------------|---------------|
 | TR-ANC-001 | `transparency` is an `https://` URI with a host. Not resolved | `https://transparency.example/entries/abc123` | missing field, empty string, non-string, `http://`, bare path, `ipfs://` |
 | TR-ANC-002 | The record's inclusion proof replays to the committed `merkle_root`, per RFC 9162 over an RFC 6962 tree. Offline, no network | a receipt whose `audit_path` reproduces `merkle_root` from the record's leaf | no receipt supplied, missing `leaf_index`/`audit_path`/`leaf_count`/`merkle_root`, non-hex audit node, out-of-range `leaf_index`, proof for a different record, record modified after anchoring |
+
+## External anchor corpus
+
+The `Anchor corpus` workflow also runs TR-ANC-002 over an external registry anchor corpus, pinned by commit and SHA-256 in [`interop/trace-anchor/pin.json`](https://github.com/agentrust-io/trace-spec/blob/main/conformance/interop/trace-anchor/pin.json). Each case records its expected decision and the `spec/registry-anchor-v1.md` section it rests on. The job fails on a disagreement that `pin.json` does not list, and reports a listed one that now agrees so the list can be shortened. Moving the pin is a reviewed change to that file.
diff --git a/conformance/interop/trace-anchor/grade.py b/conformance/interop/trace-anchor/grade.py
new file mode 100644
index 00000000..b80d0863
--- /dev/null
+++ b/conformance/interop/trace-anchor/grade.py
@@ -0,0 +1,112 @@
+"""Grade TR-ANC-002 against a pinned external registry anchor corpus.
+
+The corpus is data. This script downloads its MANIFEST.json and each case file
+from the commit named in pin.json, refuses any file whose SHA-256 differs from
+its pin, and answers every case with this repository's own
+``trace_tests.modules.tr_anc.check``. Nothing from the corpus repository is
+installed or executed.
+
+A TR-ANC-002 pass is read as ``anchored`` and anything else as ``refused``;
+each case's expected decision comes from the manifest. The job fails when the
+corpus does not hold exactly the pinned number of cases, when a file does not
+match its digest, or when a case disagrees and is not listed in
+``known_disagreements``. A listed case that now agrees is reported so that the
+list can be shortened; it does not fail the job.
+
+    python interop/trace-anchor/grade.py [--report build/anchor-corpus.json]
+"""
+
+from __future__ import annotations
+
+import argparse
+import hashlib
+import inspect
+import json
+import sys
+import urllib.request
+from pathlib import Path
+from typing import Any
+
+from trace_tests.modules import tr_anc
+
+PIN = Path(__file__).with_name("pin.json")
+RAW = "https://raw.githubusercontent.com"
+
+
+def fetch(repository: str, commit: str, path: str, sha256: str) -> bytes:
+    owner_repo = repository.removeprefix("https://github.com/")
+    url = f"{RAW}/{owner_repo}/{commit}/{path}"
+    with urllib.request.urlopen(url, timeout=30) as response:  # noqa: S310 (fixed https host)
+        data: bytes = response.read()
+    digest = hashlib.sha256(data).hexdigest()
+    if digest != sha256:
+        raise SystemExit(f"digest mismatch for {path}: got {digest}, pinned {sha256}")
+    return data
+
+
+def decide(case: dict[str, Any]) -> tuple[str, str]:
+    claim, receipt, entry = case.get("claim"), case.get("receipt"), case.get("entry")
+    if "entry" in inspect.signature(tr_anc.check).parameters:
+        findings = tr_anc.check(claim, receipt, entry)  # type: ignore[call-arg]
+    else:
+        findings = tr_anc.check(claim, receipt)
+    for finding in findings:
+        if finding.code == "TR-ANC-002":
+            passed = str(getattr(finding.status, "value", finding.status)).lower() == "pass"
+            return ("anchored" if passed else "refused"), finding.message
+    return "refused", findings[0].message if findings else "no TR-ANC finding"
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
+    parser.add_argument("--report", type=Path, help="write per-case results as JSON")
+    args = parser.parse_args()
+
+    pin = json.loads(PIN.read_text(encoding="utf-8"))
+    repository, commit = pin["repository"], pin["commit"]
+    manifest = json.loads(fetch(repository, commit, pin["manifest"], pin["manifest_sha256"]))
+    base = pin["manifest"].rsplit("/", 1)[0]
+    vectors = manifest["vectors"]
+    if len(vectors) != pin["cases"]:
+        print(f"corpus holds {len(vectors)} cases, pinned {pin['cases']}")
+        return 1
+
+    known: dict[str, str] = pin["known_disagreements"]
+    results, unexpected, resolved = [], [], []
+    for vector in vectors:
+        path = f"{base}/{vector['path']}/case.json"
+        data = fetch(repository, commit, path, vector["files"]["case.json"])
+        got, message = decide(json.loads(data))
+        want = vector["expected"]["decision"]
+        agrees = got == want
+        results.append(
+            {
+                "id": vector["id"],
+                "rule": vector["rule"],
+                "expected": want,
+                "got": got,
+                "message": message,
+            }
+        )
+        if not agrees and vector["id"] not in known:
+            unexpected.append(f"{vector['id']}: expected {want}, TR-ANC-002 says {got} ({message})")
+        if agrees and vector["id"] in known:
+            resolved.append(vector["id"])
+
+    agreed = sum(r["expected"] == r["got"] for r in results)
+    print(f"{repository}@{commit[:12]} {pin['corpus']}")
+    print(f"TR-ANC-002 agrees on {agreed} of {len(results)}")
+    print(f"known disagreements listed: {len(known)}, unexpected: {len(unexpected)}")
+    for case_id in resolved:
+        print(f"::notice::{case_id} now agrees; remove it from known_disagreements in pin.json")
+    for line in unexpected:
+        print(f"::error::{line}")
+    if args.report:
+        args.report.parent.mkdir(parents=True, exist_ok=True)
+        report = json.dumps({"pin": pin, "results": results}, indent=2) + "\n"
+        args.report.write_text(report, encoding="utf-8")
+    return 1 if unexpected else 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/conformance/interop/trace-anchor/pin.json b/conformance/interop/trace-anchor/pin.json
new file mode 100644
index 00000000..5532b523
--- /dev/null
+++ b/conformance/interop/trace-anchor/pin.json
@@ -0,0 +1,18 @@
+{
+  "corpus": "vectors-trace-anchor",
+  "repository": "https://github.com/probityai/agent-evidence-vectors",
+  "commit": "0c265d65bd0003eea2ac7641c856abfd80e3143a",
+  "manifest": "vectors-trace-anchor/MANIFEST.json",
+  "manifest_sha256": "3f22497829372efa6c5df887c59904c56050a502b160beeffe7d999fc93733f0",
+  "cases": 27,
+  "known_disagreements": {
+    "anchored-proof-only-receipt": "TR-ANC-002 requires merkle_root and leaf_count on the receipt; registry-anchor-v1 section 5.1 takes both from the entry",
+    "entry-absent": "TR-ANC-002 takes no registry entry and replays against the receipt's own root (#533)",
+    "entry-missing-ts": "TR-ANC-002 takes no registry entry, so an entry's defects are not seen (#533)",
+    "entry-producer-empty": "TR-ANC-002 takes no registry entry, so an entry's defects are not seen (#533)",
+    "receipt-count-lies": "TR-ANC-002 replays with the receipt's own leaf_count (#533)",
+    "receipt-subtree-root": "TR-ANC-002 replays against the receipt's own root, here an interior node (#533)",
+    "self-anchored-no-entry": "a one-leaf receipt naming the record's own leaf hash as root passes with no entry (#533)",
+    "self-anchored-with-real-entry": "the self-anchored record passes beside a genuine entry it is not in (#533)"
+  }
+}