diff --git a/backend/src/ea_chatbot/graph/workers/researcher/__init__.py b/backend/src/ea_chatbot/graph/workers/researcher/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/backend/src/ea_chatbot/graph/workers/researcher/state.py b/backend/src/ea_chatbot/graph/workers/researcher/state.py
new file mode 100644
index 0000000..58547a4
--- /dev/null
+++ b/backend/src/ea_chatbot/graph/workers/researcher/state.py
@@ -0,0 +1,21 @@
+from typing import TypedDict, List, Dict, Any, Optional
+from langchain_core.messages import BaseMessage
+
+class WorkerState(TypedDict):
+    """Internal state for the Researcher worker subgraph."""
+    
+    # Internal worker conversation
+    messages: List[BaseMessage]
+    
+    # The specific sub-task assigned by the Orchestrator
+    task: str
+    
+    # Search context
+    queries: List[str]
+    raw_results: List[str]
+    
+    # Number of internal retry/refinement attempts
+    iterations: int
+    
+    # The final research summary to return to the Orchestrator
+    result: Optional[str]
diff --git a/backend/tests/test_researcher_state.py b/backend/tests/test_researcher_state.py
new file mode 100644
index 0000000..2166602
--- /dev/null
+++ b/backend/tests/test_researcher_state.py
@@ -0,0 +1,13 @@
+from typing import get_type_hints, List
+from ea_chatbot.graph.workers.researcher.state import WorkerState
+
+def test_researcher_worker_state():
+    """Verify that Researcher WorkerState has the required fields."""
+    hints = get_type_hints(WorkerState)
+    
+    assert "messages" in hints
+    assert "task" in hints
+    assert "queries" in hints
+    assert "raw_results" in hints
+    assert "iterations" in hints
+    assert "result" in hints