diff --git a/surfsense_backend/app/schemas/chat_session_state.py b/surfsense_backend/app/schemas/chat_session_state.py
new file mode 100644
index 000000000..6eca0e26f
--- /dev/null
+++ b/surfsense_backend/app/schemas/chat_session_state.py
@@ -0,0 +1,29 @@
+"""
+Pydantic schemas for chat session state (live collaboration).
+"""
+
+from datetime import datetime
+from uuid import UUID
+
+from pydantic import BaseModel, ConfigDict
+
+
+class RespondingUser(BaseModel):
+    """The user that the AI is currently responding to."""
+
+    id: UUID
+    display_name: str | None = None
+    email: str
+
+    model_config = ConfigDict(from_attributes=True)
+
+
+class ChatSessionStateResponse(BaseModel):
+    """Current session state for a chat thread."""
+
+    id: int
+    thread_id: int
+    responding_to: RespondingUser | None = None
+    updated_at: datetime
+
+    model_config = ConfigDict(from_attributes=True)