diff --git a/riptide/webhook.py b/riptide/webhook.py
index 4e58f75..e082801 100644
--- a/riptide/webhook.py
+++ b/riptide/webhook.py
@@ -101,12 +101,50 @@ def get_companion():
 app = FastAPI(title="Riptide Webhook Server")
 
 # ── Synchronize rate limiting ───────────────────────────────────────────────
-# Track last synchronize time per PR to avoid T0 flooding on frequent pushes
+# Track last synchronize time per PR to avoid flooding on frequent pushes
 _SYNCHRONIZE_TIMESTAMPS: dict[str, float] = {}
 _SYNCHRONIZE_LOCK = threading.Lock()
 _SYNCHRONIZE_MIN_INTERVAL = 60.0  # seconds between synchronize processing
 
 
+def _sync_test_helper(items: list[dict]) -> list[str]:
+    """Live-test helper (WS-3 sync path): deterministic finding fixture."""
+    keys = []
+    for item in items:
+        try:
+            keys.append(item["key"])
+        except Exception as e:  # noqa: BLE001 - finding: silently ignored exception
+            pass
+    keys.sort()
+    return keys
+
+
+def _sync_test_helper_delta(items: list[dict]) -> list[str]:
+    """WS-3 delta fixture: a NEW silently-ignored exception in the delta."""
+    result = []
+    for item in items:
+        try:
+            result.append(str(item))
+        except Exception as e:  # noqa: BLE001 - finding: silently ignored exception
+            pass
+    return result
+
+
+def _sync_test_helper_delta2(items: list[dict]) -> int:
+    """WS-3 final thread-update fixture: finding in the live delta."""
+    total = 0
+    for item in items:
+        try:
+            total += int(item.get("qty", 0))
+        except Exception as e:  # noqa: BLE001 - finding: silently ignored exception
+            pass
+    return total
+
+
+# WS-3 live-test marker: final sync to exercise the canonical-thread PATCH path
+# with the delta-mapping fix deployed. See PR #73 / commit 6130294.
+
+
 def _should_process_synchronize(owner: str, repo: str, pr_number: int) -> bool:
     """Check if enough time has passed since the last synchronize for this PR."""
     global _SYNCHRONIZE_TIMESTAMPS