diff --git a/src/brief_state.py b/src/brief_state.py
new file mode 100644
index 0000000..0d92a0e
--- /dev/null
+++ b/src/brief_state.py
@@ -0,0 +1,8 @@
+from typing import TypedDict, List, Optional
+
+class BriefState(TypedDict):
+    topic: str
+    outline: List[str] | None
+    step_index: int
+    notes: List[str]
+    final_brief: str | None
\ No newline at end of file