diff --git a/backend/src/ea_chatbot/graph/workers/data_analyst/mapping.py b/backend/src/ea_chatbot/graph/workers/data_analyst/mapping.py
new file mode 100644
index 0000000..99851be
--- /dev/null
+++ b/backend/src/ea_chatbot/graph/workers/data_analyst/mapping.py
@@ -0,0 +1,39 @@
+from typing import Dict, Any, List
+from langchain_core.messages import HumanMessage, AIMessage
+from ea_chatbot.graph.state import AgentState
+from ea_chatbot.graph.workers.data_analyst.state import WorkerState
+
+def prepare_worker_input(state: AgentState) -> Dict[str, Any]:
+    """Prepare the initial state for the Data Analyst worker."""
+    checklist = state.get("checklist", [])
+    current_step = state.get("current_step", 0)
+    
+    # Get the current task description
+    task_desc = "Analyze data" # Default
+    if 0 <= current_step < len(checklist):
+        task_desc = checklist[current_step].get("task", task_desc)
+    
+    return {
+        "task": task_desc,
+        "messages": [HumanMessage(content=task_desc)], # Start worker loop with the task
+        "vfs_state": dict(state.get("vfs", {})),
+        "iterations": 0,
+        "plots": [],
+        "code": None,
+        "output": None,
+        "error": None,
+        "result": None
+    }
+
+def merge_worker_output(worker_state: WorkerState) -> Dict[str, Any]:
+    """Map worker results back to the global AgentState."""
+    result = worker_state.get("result", "Analysis complete.")
+    
+    # We bubble up the summary as an AI message
+    updates = {
+        "messages": [AIMessage(content=result)],
+        "vfs": worker_state.get("vfs_state", {}),
+        "plots": worker_state.get("plots", [])
+    }
+    
+    return updates
diff --git a/backend/tests/test_data_analyst_mapping.py b/backend/tests/test_data_analyst_mapping.py
new file mode 100644
index 0000000..e4fdc87
--- /dev/null
+++ b/backend/tests/test_data_analyst_mapping.py
@@ -0,0 +1,53 @@
+from langchain_core.messages import HumanMessage, AIMessage
+from ea_chatbot.graph.state import AgentState
+from ea_chatbot.graph.workers.data_analyst.mapping import (
+    prepare_worker_input,
+    merge_worker_output
+)
+from ea_chatbot.graph.workers.data_analyst.state import WorkerState
+
+def test_prepare_worker_input():
+    """Verify that we correctly map global state to worker input."""
+    global_state = AgentState(
+        messages=[HumanMessage(content="global message")],
+        question="original question",
+        checklist=[{"task": "Worker Task", "status": "pending"}],
+        current_step=0,
+        vfs={"old.txt": "old data"},
+        plots=[],
+        dfs={},
+        next_action="test",
+        iterations=0
+    )
+    
+    worker_input = prepare_worker_input(global_state)
+    
+    assert worker_input["task"] == "Worker Task"
+    assert "old.txt" in worker_input["vfs_state"]
+    # Internal worker messages should start fresh or with the task
+    assert len(worker_input["messages"]) == 1
+    assert worker_input["messages"][0].content == "Worker Task"
+
+def test_merge_worker_output():
+    """Verify that we correctly merge worker results back to global state."""
+    worker_state = WorkerState(
+        messages=[HumanMessage(content="internal"), AIMessage(content="summary")],
+        task="Worker Task",
+        result="Finished analysis",
+        plots=["plot1"],
+        vfs_state={"new.txt": "new data"},
+        iterations=2
+    )
+    
+    updates = merge_worker_output(worker_state)
+    
+    # We expect the 'result' to be added as an AI message to global history
+    assert len(updates["messages"]) == 1
+    assert updates["messages"][0].content == "Finished analysis"
+    
+    # VFS should be updated
+    assert "new.txt" in updates["vfs"]
+    
+    # Plots should be bubbled up
+    assert len(updates["plots"]) == 1
+    assert updates["plots"][0] == "plot1"