diff --git a/web/app/components/evaluation/components/batch-test-panel/input-fields/__tests__/input-fields-utils.spec.ts b/web/app/components/evaluation/components/batch-test-panel/input-fields/__tests__/input-fields-utils.spec.ts
new file mode 100644
index 0000000000..67ee548738
--- /dev/null
+++ b/web/app/components/evaluation/components/batch-test-panel/input-fields/__tests__/input-fields-utils.spec.ts
@@ -0,0 +1,26 @@
+import { buildTemplateCsvContent } from '../input-fields-utils'
+
+describe('input fields utils', () => {
+  describe('buildTemplateCsvContent', () => {
+    it('should append expected_output as the last CSV column', () => {
+      expect(buildTemplateCsvContent([
+        { name: 'query', type: 'string' },
+        { name: 'context', type: 'string' },
+      ])).toBe('query,context,expected_output\n')
+    })
+
+    it('should not duplicate expected_output when it already exists', () => {
+      expect(buildTemplateCsvContent([
+        { name: 'query', type: 'string' },
+        { name: 'expected_output', type: 'string' },
+      ])).toBe('query,expected_output\n')
+    })
+
+    it('should escape CSV column names before appending expected_output', () => {
+      expect(buildTemplateCsvContent([
+        { name: 'query,text', type: 'string' },
+        { name: 'answer "draft"', type: 'string' },
+      ])).toBe('"query,text","answer ""draft""",expected_output\n')
+    })
+  })
+})
diff --git a/web/app/components/evaluation/components/batch-test-panel/input-fields/input-fields-utils.ts b/web/app/components/evaluation/components/batch-test-panel/input-fields/input-fields-utils.ts
index ce21045e13..6daae07a84 100644
--- a/web/app/components/evaluation/components/batch-test-panel/input-fields/input-fields-utils.ts
+++ b/web/app/components/evaluation/components/batch-test-panel/input-fields/input-fields-utils.ts
@@ -10,6 +10,8 @@ export type InputField = {
   type: string
 }
 
+export const EXPECTED_OUTPUT_FIELD_NAME = 'expected_output'
+
 export const getGraphNodes = (graph?: Record<string, unknown>) => {
   return Array.isArray(graph?.nodes) ? graph.nodes as Node[] : []
 }
@@ -63,7 +65,12 @@ const escapeCsvCell = (value: string) => {
 }
 
 export const buildTemplateCsvContent = (inputFields: InputField[]) => {
-  return `${inputFields.map(field => escapeCsvCell(field.name)).join(',')}\n`
+  const fieldNames = inputFields.map(field => field.name)
+  const templateFieldNames = fieldNames.includes(EXPECTED_OUTPUT_FIELD_NAME)
+    ? fieldNames
+    : [...fieldNames, EXPECTED_OUTPUT_FIELD_NAME]
+
+  return `${templateFieldNames.map(escapeCsvCell).join(',')}\n`
 }
 
 export const getFileExtension = (fileName: string) => {