diff --git a/frontend/src/components/tasks/TaskDetailsPanel.tsx b/frontend/src/components/tasks/TaskDetailsPanel.tsx
index 3c6537cd..518c98fa 100644
--- a/frontend/src/components/tasks/TaskDetailsPanel.tsx
+++ b/frontend/src/components/tasks/TaskDetailsPanel.tsx
@@ -179,6 +179,32 @@ export function TaskDetailsPanel({
     }
   }, [executionState, isOpen, selectedAttempt, fetchDiff]);
 
+  // Refresh diff when coding agent completes or changes state
+  useEffect(() => {
+    if (!executionState || !isOpen || !selectedAttempt) return;
+
+    const isCodingAgentComplete =
+      executionState.execution_state === 'CodingAgentComplete';
+    const isCodingAgentFailed =
+      executionState.execution_state === 'CodingAgentFailed';
+    const isComplete = executionState.execution_state === 'Complete';
+    const hasChanges = executionState.has_changes;
+
+    // Fetch diff when coding agent completes, fails, or task is complete and has changes
+    if (
+      (isCodingAgentComplete || isCodingAgentFailed || isComplete) &&
+      hasChanges
+    ) {
+      fetchDiff();
+    }
+  }, [
+    executionState?.execution_state,
+    executionState?.has_changes,
+    isOpen,
+    selectedAttempt,
+    fetchDiff,
+  ]);
+
   // Handle ESC key locally to prevent global navigation
   useEffect(() => {
     if (!isOpen || isDialogOpen) return;