diff --git a/web/app/components/evaluation/components/custom-metric-editor.tsx b/web/app/components/evaluation/components/custom-metric-editor-card.tsx
similarity index 97%
rename from web/app/components/evaluation/components/custom-metric-editor.tsx
rename to web/app/components/evaluation/components/custom-metric-editor-card.tsx
index 2c35566bddf..3bc1db061bf 100644
--- a/web/app/components/evaluation/components/custom-metric-editor.tsx
+++ b/web/app/components/evaluation/components/custom-metric-editor-card.tsx
@@ -17,7 +17,7 @@ import { getEvaluationMockConfig } from '../mock'
 import { isCustomMetricConfigured, useEvaluationStore } from '../store'
 import { groupFieldOptions } from '../utils'
 
-type CustomMetricEditorProps = EvaluationResourceProps & {
+type CustomMetricEditorCardProps = EvaluationResourceProps & {
   metric: EvaluationMetric
 }
 
@@ -76,11 +76,11 @@ function MappingRow({
   )
 }
 
-const CustomMetricEditor = ({
+const CustomMetricEditorCard = ({
   resourceType,
   resourceId,
   metric,
-}: CustomMetricEditorProps) => {
+}: CustomMetricEditorCardProps) => {
   const { t } = useTranslation('evaluation')
   const config = getEvaluationMockConfig(resourceType)
   const setCustomMetricWorkflow = useEvaluationStore(state => state.setCustomMetricWorkflow)
@@ -148,4 +148,4 @@ const CustomMetricEditor = ({
   )
 }
 
-export default CustomMetricEditor
+export default CustomMetricEditorCard
diff --git a/web/app/components/evaluation/components/metric-section.tsx b/web/app/components/evaluation/components/metric-section.tsx
deleted file mode 100644
index 704b432ca31..00000000000
--- a/web/app/components/evaluation/components/metric-section.tsx
+++ /dev/null
@@ -1,93 +0,0 @@
-'use client'
-
-import type { EvaluationResourceProps } from '../types'
-import { useTranslation } from 'react-i18next'
-import Badge from '@/app/components/base/badge'
-import Button from '@/app/components/base/button'
-import { useEvaluationResource, useEvaluationStore } from '../store'
-import CustomMetricEditor from './custom-metric-editor'
-import MetricSelector from './metric-selector'
-import { InlineSectionHeader } from './section-header'
-
-const MetricSection = ({
-  resourceType,
-  resourceId,
-}: EvaluationResourceProps) => {
-  const { t } = useTranslation('evaluation')
-  const resource = useEvaluationResource(resourceType, resourceId)
-  const removeMetric = useEvaluationStore(state => state.removeMetric)
-  const hasMetrics = resource.metrics.length > 0
-
-  return (
-    <section className="max-w-[700px] py-4">
-      <InlineSectionHeader
-        title={t('metrics.title')}
-        tooltip={t('metrics.description')}
-      />
-      <div className="mt-2 space-y-3">
-        {!hasMetrics && (
-          <div className="flex items-center gap-5 rounded-xl bg-background-section px-3 py-3">
-            <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-[10px] border-[0.5px] border-components-card-border bg-components-card-bg shadow-md">
-              <span aria-hidden="true" className="i-ri-bar-chart-horizontal-line h-6 w-6 text-text-primary" />
-            </div>
-            <div className="text-text-tertiary system-xs-regular">
-              {t('metrics.description')}
-            </div>
-          </div>
-        )}
-        {resource.metrics.map(metric => (
-          <div key={metric.id} className="rounded-2xl border border-divider-subtle bg-components-card-bg p-4">
-            <div className="flex items-start justify-between gap-3">
-              <div>
-                <div className="text-text-primary system-sm-semibold">{metric.label}</div>
-                <div className="mt-1 text-text-tertiary system-xs-regular">{metric.description}</div>
-                <div className="mt-3 flex flex-wrap gap-2">
-                  {metric.badges.map(badge => (
-                    <Badge key={badge} className={badge === 'Workflow' ? 'badge-accent' : ''}>{badge}</Badge>
-                  ))}
-                </div>
-                {metric.kind === 'builtin' && (
-                  <div className="mt-3 rounded-xl bg-background-default-subtle px-3 py-2">
-                    <div className="text-text-secondary system-2xs-medium-uppercase">{t('metrics.nodesLabel')}</div>
-                    <div className="mt-2 flex flex-wrap gap-2">
-                      {metric.nodeInfoList?.length
-                        ? metric.nodeInfoList.map(nodeInfo => (
-                            <Badge key={nodeInfo.node_id} className="badge-accent">
-                              {nodeInfo.title}
-                            </Badge>
-                          ))
-                        : (
-                            <span className="text-text-tertiary system-xs-regular">{t('metrics.nodesAll')}</span>
-                          )}
-                    </div>
-                  </div>
-                )}
-              </div>
-              <Button
-                size="small"
-                variant="ghost"
-                aria-label={t('metrics.remove')}
-                onClick={() => removeMetric(resourceType, resourceId, metric.id)}
-              >
-                <span aria-hidden="true" className="i-ri-delete-bin-line h-4 w-4" />
-              </Button>
-            </div>
-            {metric.kind === 'custom-workflow' && (
-              <CustomMetricEditor
-                resourceType={resourceType}
-                resourceId={resourceId}
-                metric={metric}
-              />
-            )}
-          </div>
-        ))}
-        <MetricSelector
-          resourceType={resourceType}
-          resourceId={resourceId}
-        />
-      </div>
-    </section>
-  )
-}
-
-export default MetricSection
diff --git a/web/app/components/evaluation/components/metric-section/__tests__/index.spec.tsx b/web/app/components/evaluation/components/metric-section/__tests__/index.spec.tsx
new file mode 100644
index 00000000000..b112d76f474
--- /dev/null
+++ b/web/app/components/evaluation/components/metric-section/__tests__/index.spec.tsx
@@ -0,0 +1,94 @@
+import { act, fireEvent, render, screen } from '@testing-library/react'
+import MetricSection from '..'
+import { useEvaluationStore } from '../../../store'
+
+const mockUseAvailableEvaluationMetrics = vi.hoisted(() => vi.fn())
+const mockUseEvaluationNodeInfoMutation = vi.hoisted(() => vi.fn())
+
+vi.mock('@/service/use-evaluation', () => ({
+  useAvailableEvaluationMetrics: (...args: unknown[]) => mockUseAvailableEvaluationMetrics(...args),
+  useEvaluationNodeInfoMutation: (...args: unknown[]) => mockUseEvaluationNodeInfoMutation(...args),
+}))
+
+const resourceType = 'workflow' as const
+const resourceId = 'metric-section-resource'
+
+const renderMetricSection = () => {
+  return render(<MetricSection resourceType={resourceType} resourceId={resourceId} />)
+}
+
+describe('MetricSection', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    useEvaluationStore.setState({ resources: {} })
+
+    mockUseAvailableEvaluationMetrics.mockReturnValue({
+      data: {
+        metrics: ['answer-correctness'],
+      },
+      isLoading: false,
+    })
+
+    mockUseEvaluationNodeInfoMutation.mockReturnValue({
+      isPending: false,
+      mutate: vi.fn(),
+    })
+  })
+
+  // Verify the empty state block extracted from MetricSection.
+  describe('Empty State', () => {
+    it('should render the metric empty state when no metrics are selected', () => {
+      renderMetricSection()
+
+      expect(screen.getByText('evaluation.metrics.description')).toBeInTheDocument()
+      expect(screen.getByRole('button', { name: 'evaluation.metrics.add' })).toBeInTheDocument()
+    })
+  })
+
+  // Verify the extracted builtin metric card presentation and removal flow.
+  describe('Builtin Metric Card', () => {
+    it('should render node badges for a builtin metric and remove it when delete is clicked', () => {
+      act(() => {
+        useEvaluationStore.getState().addBuiltinMetric(resourceType, resourceId, 'answer-correctness', [
+          { node_id: 'node-answer', title: 'Answer Node', type: 'llm' },
+        ])
+      })
+
+      renderMetricSection()
+
+      expect(screen.getByText('Answer Correctness')).toBeInTheDocument()
+      expect(screen.getByText('Answer Node')).toBeInTheDocument()
+
+      fireEvent.click(screen.getByRole('button', { name: 'evaluation.metrics.remove' }))
+
+      expect(screen.queryByText('Answer Correctness')).not.toBeInTheDocument()
+      expect(screen.getByText('evaluation.metrics.description')).toBeInTheDocument()
+    })
+
+    it('should render the all-nodes label when a builtin metric has no node selection', () => {
+      act(() => {
+        useEvaluationStore.getState().addBuiltinMetric(resourceType, resourceId, 'answer-correctness', [])
+      })
+
+      renderMetricSection()
+
+      expect(screen.getByText('evaluation.metrics.nodesAll')).toBeInTheDocument()
+    })
+  })
+
+  // Verify the extracted custom metric editor card renders inside the metric card.
+  describe('Custom Metric Card', () => {
+    it('should render the custom metric editor card when a custom metric is added', () => {
+      act(() => {
+        useEvaluationStore.getState().addCustomMetric(resourceType, resourceId)
+      })
+
+      renderMetricSection()
+
+      expect(screen.getByText('Custom Evaluator')).toBeInTheDocument()
+      expect(screen.getByText('evaluation.metrics.custom.title')).toBeInTheDocument()
+      expect(screen.getByText('evaluation.metrics.custom.warningBadge')).toBeInTheDocument()
+      expect(screen.getByRole('button', { name: 'evaluation.metrics.custom.addMapping' })).toBeInTheDocument()
+    })
+  })
+})
diff --git a/web/app/components/evaluation/components/metric-section/index.tsx b/web/app/components/evaluation/components/metric-section/index.tsx
new file mode 100644
index 00000000000..582fcbfa301
--- /dev/null
+++ b/web/app/components/evaluation/components/metric-section/index.tsx
@@ -0,0 +1,47 @@
+'use client'
+
+import type { EvaluationResourceProps } from '../../types'
+import { useTranslation } from 'react-i18next'
+import { useEvaluationResource } from '../../store'
+import MetricSelector from '../metric-selector'
+import { InlineSectionHeader } from '../section-header'
+import MetricCard from './metric-card'
+import MetricSectionEmptyState from './metric-section-empty-state'
+
+const MetricSection = ({
+  resourceType,
+  resourceId,
+}: EvaluationResourceProps) => {
+  const { t } = useTranslation('evaluation')
+  const resource = useEvaluationResource(resourceType, resourceId)
+  const hasMetrics = resource.metrics.length > 0
+
+  return (
+    <section className="max-w-[700px] py-4">
+      <InlineSectionHeader
+        title={t('metrics.title')}
+        tooltip={t('metrics.description')}
+      />
+      <div className="mt-2 space-y-3">
+        {!hasMetrics && <MetricSectionEmptyState description={t('metrics.description')} />}
+        {resource.metrics.map(metric => (
+          <MetricCard
+            key={metric.id}
+            resourceType={resourceType}
+            resourceId={resourceId}
+            metric={metric}
+            nodesLabel={t('metrics.nodesLabel')}
+            nodesAllLabel={t('metrics.nodesAll')}
+            removeLabel={t('metrics.remove')}
+          />
+        ))}
+        <MetricSelector
+          resourceType={resourceType}
+          resourceId={resourceId}
+        />
+      </div>
+    </section>
+  )
+}
+
+export default MetricSection
diff --git a/web/app/components/evaluation/components/metric-section/metric-card.tsx b/web/app/components/evaluation/components/metric-section/metric-card.tsx
new file mode 100644
index 00000000000..70af26a2dce
--- /dev/null
+++ b/web/app/components/evaluation/components/metric-section/metric-card.tsx
@@ -0,0 +1,74 @@
+'use client'
+
+import type { EvaluationMetric, EvaluationResourceProps } from '../../types'
+import Badge from '@/app/components/base/badge'
+import Button from '@/app/components/base/button'
+import { useEvaluationStore } from '../../store'
+import CustomMetricEditorCard from '../custom-metric-editor-card'
+
+type MetricCardProps = EvaluationResourceProps & {
+  metric: EvaluationMetric
+  nodesLabel: string
+  nodesAllLabel: string
+  removeLabel: string
+}
+
+const MetricCard = ({
+  resourceType,
+  resourceId,
+  metric,
+  nodesLabel,
+  nodesAllLabel,
+  removeLabel,
+}: MetricCardProps) => {
+  const removeMetric = useEvaluationStore(state => state.removeMetric)
+
+  return (
+    <div className="rounded-2xl border border-divider-subtle bg-components-card-bg p-4">
+      <div className="flex items-start justify-between gap-3">
+        <div>
+          <div className="text-text-primary system-sm-semibold">{metric.label}</div>
+          <div className="mt-1 text-text-tertiary system-xs-regular">{metric.description}</div>
+          <div className="mt-3 flex flex-wrap gap-2">
+            {metric.badges.map(badge => (
+              <Badge key={badge} className={badge === 'Workflow' ? 'badge-accent' : ''}>{badge}</Badge>
+            ))}
+          </div>
+          {metric.kind === 'builtin' && (
+            <div className="mt-3 rounded-xl bg-background-default-subtle px-3 py-2">
+              <div className="text-text-secondary system-2xs-medium-uppercase">{nodesLabel}</div>
+              <div className="mt-2 flex flex-wrap gap-2">
+                {metric.nodeInfoList?.length
+                  ? metric.nodeInfoList.map(nodeInfo => (
+                      <Badge key={nodeInfo.node_id} className="badge-accent">
+                        {nodeInfo.title}
+                      </Badge>
+                    ))
+                  : (
+                      <span className="text-text-tertiary system-xs-regular">{nodesAllLabel}</span>
+                    )}
+              </div>
+            </div>
+          )}
+        </div>
+        <Button
+          size="small"
+          variant="ghost"
+          aria-label={removeLabel}
+          onClick={() => removeMetric(resourceType, resourceId, metric.id)}
+        >
+          <span aria-hidden="true" className="i-ri-delete-bin-line h-4 w-4" />
+        </Button>
+      </div>
+      {metric.kind === 'custom-workflow' && (
+        <CustomMetricEditorCard
+          resourceType={resourceType}
+          resourceId={resourceId}
+          metric={metric}
+        />
+      )}
+    </div>
+  )
+}
+
+export default MetricCard
diff --git a/web/app/components/evaluation/components/metric-section/metric-section-empty-state.tsx b/web/app/components/evaluation/components/metric-section/metric-section-empty-state.tsx
new file mode 100644
index 00000000000..657cdcbdd1b
--- /dev/null
+++ b/web/app/components/evaluation/components/metric-section/metric-section-empty-state.tsx
@@ -0,0 +1,18 @@
+type MetricSectionEmptyStateProps = {
+  description: string
+}
+
+const MetricSectionEmptyState = ({ description }: MetricSectionEmptyStateProps) => {
+  return (
+    <div className="flex items-center gap-5 rounded-xl bg-background-section px-3 py-3">
+      <div className="flex h-10 w-10 shrink-0 items-center justify-center rounded-[10px] border-[0.5px] border-components-card-border bg-components-card-bg shadow-md">
+        <span aria-hidden="true" className="i-ri-bar-chart-horizontal-line h-6 w-6 text-text-primary" />
+      </div>
+      <div className="text-text-tertiary system-xs-regular">
+        {description}
+      </div>
+    </div>
+  )
+}
+
+export default MetricSectionEmptyState