diff --git a/src/mind_reader/state_machines/base_event.py b/src/mind_reader/state_machines/base_event.py
new file mode 100644
index 0000000..aedf931
--- /dev/null
+++ b/src/mind_reader/state_machines/base_event.py
@@ -0,0 +1,22 @@
+from dataclasses import asdict, dataclass, is_dataclass
+from enum import StrEnum
+from typing import Any
+
+
+def _factory(d: list[tuple[str, Any]]) -> dict[str, Any]:
+    def _convert(obj: Any) -> Any:
+        if isinstance(obj, StrEnum):
+            return obj.value
+        if isinstance(obj, list | tuple):
+            return [_convert(item) for item in obj]
+        if isinstance(obj, dict):
+            return {k: _convert(v) for k, v in obj.items()}
+        return obj
+
+    return {k: _convert(v) for k, v in d}
+
+
+@dataclass(frozen=True)
+class BaseEvent:
+    def to_payload(self) -> dict[str, Any]:
+        return asdict(self, dict_factory=_factory)