diff --git a/modules/fifth-domain-lighthouse-sanitized-mirror/module.lock.hdlp b/modules/fifth-domain-lighthouse-sanitized-mirror/module.lock.hdlp
index c0e215e..89fa4d2 100644
--- a/modules/fifth-domain-lighthouse-sanitized-mirror/module.lock.hdlp
+++ b/modules/fifth-domain-lighthouse-sanitized-mirror/module.lock.hdlp
@@ -2,7 +2,7 @@ schema: tcs.module-lock/v1
 module_id: TCS-AGENT-SANITIZED-MIRROR-001
 module_source_sha256: 1210b30c7dabc56b8b989763230a3cf56c0fe02a3b409be5f3833dee9853d771
 module_gir_sha256: 0e7b1bbd5f3f8dbc83df6c72e4a1e0532b6f44beed21c8c8315f85cc76096712
-runtime_sha256: b5c87c3a4d71e5c095e0b4f43c4c26f2b27afde19d972906f383587c7dcdefa4
+runtime_sha256: 4b396550a144fa83614e340a34d087a96e2fb3e18045dabc801150f63b93c211
 mirror_map_sha256: a03b5ba9e06f5fd3f626301305d75add0332ae06948a67c8bcd03c3cab248fe1
 protocol_source_sha256: cf198e7939e4ab70828b74cef8a2b84c2dac2ff262582bb3d5663904d602d71b
 protocol_gir_sha256: 69f1a2a5cfc5ee61bdc2bf2065751d9cc41b9f662b28c35e61b393fd2187e1dc
diff --git a/server-tools/fifth-domain-lighthouse-mirror/public_mirror_agent.py b/server-tools/fifth-domain-lighthouse-mirror/public_mirror_agent.py
index 66290ad..3efbc9e 100644
--- a/server-tools/fifth-domain-lighthouse-mirror/public_mirror_agent.py
+++ b/server-tools/fifth-domain-lighthouse-mirror/public_mirror_agent.py
@@ -126,9 +126,12 @@ def sync_architecture(repo: Path, state: Path, commit: str | None = None) -> dic
         "contains_private_source_body": False,
         "authority_granted": False,
     }
+    snapshot["projection_fingerprint"] = sha(stable(projections))
     snapshot["freshness_token"] = sha(stable(snapshot))
     current = state / "architecture" / "CURRENT.json"
     previous = json.loads(current.read_text()) if current.is_file() else None
+    if previous and previous.get("projection_fingerprint") == snapshot["projection_fingerprint"]:
+        return {"outcome":"PASS", "state":"MIRROR_PUBLIC_ARCHITECTURE_UNCHANGED", "observed_commit":commit, "current_source_commit":previous.get("source_commit"), "freshness_token":previous.get("freshness_token")}
     if previous and previous.get("freshness_token") == snapshot["freshness_token"]:
         return {"outcome":"PASS", "state":"MIRROR_IDEMPOTENT", "freshness_token":snapshot["freshness_token"]}
     current_sha = atomic_json(current, snapshot)
diff --git a/server-tools/fifth-domain-lighthouse-mirror/test_public_mirror_agent.py b/server-tools/fifth-domain-lighthouse-mirror/test_public_mirror_agent.py
index 9ffe8ad..f8b1bbd 100644
--- a/server-tools/fifth-domain-lighthouse-mirror/test_public_mirror_agent.py
+++ b/server-tools/fifth-domain-lighthouse-mirror/test_public_mirror_agent.py
@@ -33,6 +33,8 @@ class MirrorAgentTest(unittest.TestCase):
             body = (Path(temp) / "architecture/CURRENT.json").read_text()
             self.assertNotIn("/Volumes/", body)
             self.assertNotIn("continuity-memory", body)
+            unchanged = M.sync_architecture(ROOT, Path(temp))
+            self.assertEqual(unchanged["state"], "MIRROR_PUBLIC_ARCHITECTURE_UNCHANGED")
 
     def test_no_persona_decision_no_candidate(self):
         with tempfile.TemporaryDirectory() as temp: