diff --git a/src/Mod/FreeCADExchange/AutoRouting.py b/src/Mod/FreeCADExchange/AutoRouting.py
index 6b3adee..008d806 100644
--- a/src/Mod/FreeCADExchange/AutoRouting.py
+++ b/src/Mod/FreeCADExchange/AutoRouting.py
@@ -1138,6 +1138,7 @@ def route_all_from_payload(doc, payload, options=None):
             }
         )
     report["missing_endpoint_uuids"] = sorted(missing_endpoint_uuids)
+    _write_auto_route_batch_diagnostic(doc, report)
     return report
 
 
@@ -1180,6 +1181,53 @@ def format_route_all_report(report):
     return message
 
 
+def _clear_auto_route_batch_diagnostics(doc):
+    group = WiringObjects.ensure_diagnostic_group(doc, _project_uuid(doc))
+    removed = 0
+    for obj in list(getattr(group, "Group", []) or []):
+        if (getattr(obj, "QetDiagnosticKind", "") or "").strip() != "AutoRouteBatch":
+            continue
+        try:
+            group.removeObject(obj)
+        except Exception:
+            try:
+                group.Group = [
+                    candidate
+                    for candidate in list(getattr(group, "Group", []) or [])
+                    if candidate is not obj
+                ]
+            except Exception:
+                pass
+        try:
+            if doc.getObject(getattr(obj, "Name", "")) is not None:
+                doc.removeObject(obj.Name)
+                removed += 1
+        except Exception:
+            pass
+    return removed
+
+
+def _write_auto_route_batch_diagnostic(doc, report):
+    if doc is None or not isinstance(report, dict):
+        return None
+    if not report.get("errors") and not report.get("missing_endpoint_uuids") and report.get("collision_warnings", 0) <= 0:
+        return None
+    project_uuid = _project_uuid(doc)
+    group = WiringObjects.ensure_diagnostic_group(doc, project_uuid)
+    _clear_auto_route_batch_diagnostics(doc)
+    diagnostic = doc.addObject("App::DocumentObjectGroup", _unique_name(doc, "QETAutoRouteDiagnostic"))
+    diagnostic.Label = "QET Auto Route Diagnostic"
+    _set_string(diagnostic, "QetDiagnosticKind", "AutoRouteBatch", "QET diagnostic kind")
+    _set_string(
+        diagnostic,
+        "QetDiagnosticJson",
+        json.dumps(report, ensure_ascii=False),
+        "QET auto-routing batch diagnostic payload",
+    )
+    group.addObject(diagnostic)
+    return diagnostic
+
+
 def _iter_wire_tasks(doc):
     try:
         task_group = doc.getObject("QETWiring_01_Tasks")
diff --git a/tests/python/freecad_exchange_auto_routing_test.py b/tests/python/freecad_exchange_auto_routing_test.py
index 07c4de3..0ee9b9b 100644
--- a/tests/python/freecad_exchange_auto_routing_test.py
+++ b/tests/python/freecad_exchange_auto_routing_test.py
@@ -929,6 +929,34 @@ class AutoRoutingTest(unittest.TestCase):
         self.assertTrue(report["missing_endpoint_samples"][0]["start_found"])
         self.assertFalse(report["missing_endpoint_samples"][0]["end_found"])
 
+    def test_route_all_writes_diagnostic_object_for_missing_terminal(self):
+        _install_fake_freecad()
+        terminal_objects, _wiring_objects, _routing_network, auto_routing = _reload_modules()
+        app = sys.modules["FreeCAD"]
+        doc = FakeDocument()
+        terminal_objects.ensure_root_group(doc, "project-1")
+        _terminal(doc, terminal_objects, "TerminalStart", "terminal-start", app.Vector(0, 0, 0))
+        payload = {
+            "project_uuid": "project-1",
+            "wires": [
+                {
+                    "wire_id": "wire-1",
+                    "start_terminal_uuid": "terminal-start",
+                    "end_terminal_uuid": "terminal-missing",
+                }
+            ],
+        }
+
+        report = auto_routing.route_all_from_payload(doc, payload)
+        diagnostic_group = doc.getObject("QETWiring_05_Diagnostics")
+
+        self.assertEqual(1, report["skipped_missing_terminal"])
+        self.assertIsNotNone(diagnostic_group)
+        self.assertEqual(1, len(diagnostic_group.Group))
+        diagnostic = diagnostic_group.Group[0]
+        self.assertEqual("AutoRouteBatch", diagnostic.QetDiagnosticKind)
+        self.assertIn("terminal-missing", diagnostic.QetDiagnosticJson)
+
     def test_route_all_report_calls_out_local_unbound_terminals(self):
         _install_fake_freecad()
         terminal_objects, _wiring_objects, _routing_network, auto_routing = _reload_modules()