diff --git a/loopx/event_sourced_state.py b/loopx/event_sourced_state.py
index e4ef42ba31..82f97dffc0 100644
--- a/loopx/event_sourced_state.py
+++ b/loopx/event_sourced_state.py
@@ -946,13 +946,11 @@ def build_state_projection(
         kind = event["event_type"]
         edits = kind in (TODO_ADDED, TODO_UPDATED)
         order = payload.get("planner_order") if kind == TODO_ADDED else None
-        if order is not None:
-            if isinstance(order, bool):
-                raise StateEventError("planner_order must be an integer")
-            try:
-                order = int(order)
-            except (ValueError, TypeError, OverflowError) as exc:
-                raise StateEventError("planner_order must be an integer") from exc
+        # The typed fold rejects non-integer orders, so the adapter must not
+        # coerce them first: truncating 1.5 to 1 would sort a Todo by one value
+        # and report another. Every producer of this payload writes an integer.
+        if order is not None and (isinstance(order, bool) or not isinstance(order, int)):
+            raise StateEventError("planner_order must be an integer")
         sequence = event.get("append_sequence")
         for value in (order, sequence):
             if value is not None and abs(value) > 2**53 - 1:
diff --git a/tests/control_plane/test_event_replay_integrity.py b/tests/control_plane/test_event_replay_integrity.py
index e3b1b92bb3..f113f4a296 100644
--- a/tests/control_plane/test_event_replay_integrity.py
+++ b/tests/control_plane/test_event_replay_integrity.py
@@ -119,3 +119,29 @@ def measured(method, params, **kwargs):
     # Duplicate identity protection must survive a batch boundary as well.
     with pytest.raises(StateEventError, match="already exists"):
         build_state_projection([*source, event("todo_added", 4101, title="Cannot reset history")])
+
+
+def test_fractional_planner_order_is_rejected_before_typing():
+    # The adapter used to truncate 1.5 to 1, so the fold sorted by one value
+    # while the projection still reported the original fraction.
+    with pytest.raises(StateEventError, match="planner_order must be an integer"):
+        build_state_projection([
+            event("todo_added", 1, title="Fractional", planner_order=1.5),
+            event("todo_added", 2, title="Integer", planner_order=1, todo_id="todo_beta"),
+        ])
+
+
+@pytest.mark.parametrize("order", [True, "1", [1], {"value": 1}])
+def test_non_integer_planner_order_forms_are_rejected(order):
+    with pytest.raises(StateEventError, match="planner_order must be an integer"):
+        build_state_projection([event("todo_added", 1, title="Bad order", planner_order=order)])
+
+
+def test_integer_and_absent_planner_order_still_project():
+    result = build_state_projection([
+        event("todo_added", 1, title="First", planner_order=3),
+        event("todo_added", 2, title="Second", todo_id="todo_beta"),
+    ])
+    items = result["agent_todos"]["items"]
+    assert [item["todo_id"] for item in items] == ["todo_alpha", "todo_beta"]
+    assert items[0]["planner_order"] == 3