diff --git a/nanobot/triggers/local_types.py b/nanobot/triggers/local_types.py
index f7343963..d3fa0a28 100644
--- a/nanobot/triggers/local_types.py
+++ b/nanobot/triggers/local_types.py
@@ -16,6 +16,13 @@ def _int_or_zero(value: Any) -> int:
     return 0 if value is None or value == "" else int(value)
 
 
+def _optional_int(value: Any) -> int | None:
+    """Coerce a stored JSON numeric; null/blank stays None."""
+    if value is None or value == "":
+        return None
+    return int(value)
+
+
 @dataclass
 class TriggerRunRecord:
     """A single local trigger delivery record."""
@@ -77,7 +84,7 @@ class LocalTrigger:
             origin_metadata=dict(_get(data, "originMetadata", "origin_metadata", {}) or {}),
             created_at_ms=_int_or_zero(_get(data, "createdAtMs", "created_at_ms", 0)),
             updated_at_ms=_int_or_zero(_get(data, "updatedAtMs", "updated_at_ms", 0)),
-            last_run_at_ms=_get(data, "lastRunAtMs", "last_run_at_ms"),
+            last_run_at_ms=_optional_int(_get(data, "lastRunAtMs", "last_run_at_ms")),
             last_status=_get(data, "lastStatus", "last_status"),  # type: ignore[arg-type]
             last_error=_get(data, "lastError", "last_error"),
             run_history=history,
diff --git a/tests/triggers/test_local_triggers.py b/tests/triggers/test_local_triggers.py
index 41fe91d0..d4fd279f 100644
--- a/tests/triggers/test_local_triggers.py
+++ b/tests/triggers/test_local_triggers.py
@@ -585,3 +585,35 @@ def test_local_trigger_from_dict_accepts_null_run_at_ms() -> None:
     )
     assert delivery.created_at_ms == 0
     assert delivery.attempts == 0
+
+
+def test_local_trigger_from_dict_coerces_string_last_run_at_ms() -> None:
+    """String lastRunAtMs must coerce to int like cron store ms fields."""
+    trigger = LocalTrigger.from_dict(
+        {
+            "id": "t1",
+            "name": "n",
+            "enabled": True,
+            "channel": "websocket",
+            "chatId": "c1",
+            "sessionKey": "websocket:c1",
+            "lastRunAtMs": "1710000000000",
+            "createdAtMs": 1,
+            "updatedAtMs": 1,
+        }
+    )
+    assert trigger.last_run_at_ms == 1710000000000
+    assert trigger.last_run_at_ms < 1710000000001
+
+    trigger_null = LocalTrigger.from_dict(
+        {
+            "id": "t2",
+            "name": "n",
+            "enabled": True,
+            "sessionKey": "websocket:c1",
+            "lastRunAtMs": None,
+            "createdAtMs": 1,
+            "updatedAtMs": 1,
+        }
+    )
+    assert trigger_null.last_run_at_ms is None