diff --git a/app/sft.py b/app/sft.py
index 929b98a..ab439f1 100644
--- a/app/sft.py
+++ b/app/sft.py
@@ -151,10 +151,21 @@ def get_queue(page: int = 1, per_page: int = 20):
 
 # ── POST /submit ───────────────────────────────────────────────────────────
 
+FailureCategory = Literal[
+    "scoring_artifact",
+    "style_violation",
+    "partial_answer",
+    "wrong_answer",
+    "format_error",
+    "hallucination",
+]
+
+
 class SubmitRequest(BaseModel):
     id: str
     action: Literal["correct", "discard", "flag"]
     corrected_response: str | None = None
+    failure_category: FailureCategory | None = None
 
 
 @router.post("/submit")
@@ -174,7 +185,12 @@ def post_submit(req: SubmitRequest):
         raise HTTPException(409, f"Record is not in needs_review state (current: {record.get('status')})")
 
     if req.action == "correct":
-        records[idx] = {**record, "status": "approved", "corrected_response": req.corrected_response}
+        records[idx] = {
+            **record,
+            "status": "approved",
+            "corrected_response": req.corrected_response,
+            "failure_category": req.failure_category,
+        }
         _write_candidates(records)
         append_jsonl(_approved_file(), records[idx])
     elif req.action == "discard":
diff --git a/tests/test_sft.py b/tests/test_sft.py
index ed808b1..e3c98f9 100644
--- a/tests/test_sft.py
+++ b/tests/test_sft.py
@@ -232,6 +232,41 @@ def test_submit_already_approved_returns_409(client, tmp_path):
     assert r.status_code == 409
 
 
+def test_submit_correct_stores_failure_category(client, tmp_path):
+    _populate_candidates(tmp_path, [_make_record("a")])
+    r = client.post("/api/sft/submit", json={
+        "id": "a", "action": "correct",
+        "corrected_response": "def add(a, b): return a + b",
+        "failure_category": "style_violation",
+    })
+    assert r.status_code == 200
+    from app import sft as sft_module
+    records = sft_module._read_candidates()
+    assert records[0]["failure_category"] == "style_violation"
+
+
+def test_submit_correct_null_failure_category(client, tmp_path):
+    _populate_candidates(tmp_path, [_make_record("a")])
+    r = client.post("/api/sft/submit", json={
+        "id": "a", "action": "correct",
+        "corrected_response": "def add(a, b): return a + b",
+    })
+    assert r.status_code == 200
+    from app import sft as sft_module
+    records = sft_module._read_candidates()
+    assert records[0]["failure_category"] is None
+
+
+def test_submit_invalid_failure_category_returns_422(client, tmp_path):
+    _populate_candidates(tmp_path, [_make_record("a")])
+    r = client.post("/api/sft/submit", json={
+        "id": "a", "action": "correct",
+        "corrected_response": "def add(a, b): return a + b",
+        "failure_category": "nonsense",
+    })
+    assert r.status_code == 422
+
+
 # ── /api/sft/undo ────────────────────────────────────────────────────────────
 
 def test_undo_restores_discarded_to_needs_review(client, tmp_path):
diff --git a/web/src/components/SftCard.test.ts b/web/src/components/SftCard.test.ts
index 6834987..59b5e32 100644
--- a/web/src/components/SftCard.test.ts
+++ b/web/src/components/SftCard.test.ts
@@ -13,6 +13,7 @@ const LOW_QUALITY_ITEM: SftQueueItem = {
   model_response: 'def add(a, b): return a - b',
   corrected_response: null, quality_score: 0.2,
   failure_reason: 'pattern_match: 0/2 matched',
+  failure_category: null,
   task_id: 'code-fn', task_type: 'code', task_name: 'Code: Write a function',
   model_id: 'Qwen/Qwen2.5-3B', model_name: 'Qwen2.5-3B',
   node_id: 'heimdall', gpu_id: 0, tokens_per_sec: 38.4,
@@ -68,15 +69,17 @@ describe('SftCard', () => {
     expect(w.emitted('correct')).toBeTruthy()
   })
 
-  it('clicking Discard button emits discard', async () => {
+  it('clicking Discard button then confirming emits discard', async () => {
     const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
     await w.find('[data-testid="discard-btn"]').trigger('click')
+    await w.find('[data-testid="confirm-pending-btn"]').trigger('click')
     expect(w.emitted('discard')).toBeTruthy()
   })
 
-  it('clicking Flag Model button emits flag', async () => {
+  it('clicking Flag Model button then confirming emits flag', async () => {
     const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
     await w.find('[data-testid="flag-btn"]').trigger('click')
+    await w.find('[data-testid="confirm-pending-btn"]').trigger('click')
     expect(w.emitted('flag')).toBeTruthy()
   })
 
@@ -95,4 +98,82 @@ describe('SftCard', () => {
     const w = mount(SftCard, { props: { item } })
     expect(w.find('.failure-reason').exists()).toBe(false)
   })
+
+  // ── Failure category chip-group ───────────────────────────────────
+  it('failure category section hidden when not correcting and no pending action', () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
+    expect(w.find('[data-testid="failure-category-section"]').exists()).toBe(false)
+  })
+
+  it('failure category section shown when correcting prop is true', () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM, correcting: true } })
+    expect(w.find('[data-testid="failure-category-section"]').exists()).toBe(true)
+  })
+
+  it('renders all six category chips when correcting', () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM, correcting: true } })
+    const chips = w.findAll('.category-chip')
+    expect(chips).toHaveLength(6)
+  })
+
+  it('clicking a category chip selects it (adds active class)', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM, correcting: true } })
+    const chip = w.find('[data-testid="category-chip-wrong_answer"]')
+    await chip.trigger('click')
+    expect(chip.classes()).toContain('category-chip--active')
+  })
+
+  it('clicking the active chip again deselects it', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM, correcting: true } })
+    const chip = w.find('[data-testid="category-chip-hallucination"]')
+    await chip.trigger('click')
+    expect(chip.classes()).toContain('category-chip--active')
+    await chip.trigger('click')
+    expect(chip.classes()).not.toContain('category-chip--active')
+  })
+
+  it('only one chip can be active at a time', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM, correcting: true } })
+    await w.find('[data-testid="category-chip-wrong_answer"]').trigger('click')
+    await w.find('[data-testid="category-chip-hallucination"]').trigger('click')
+    const active = w.findAll('.category-chip--active')
+    expect(active).toHaveLength(1)
+    expect(active[0].attributes('data-testid')).toBe('category-chip-hallucination')
+  })
+
+  it('clicking Discard shows pending action row with category section', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
+    await w.find('[data-testid="discard-btn"]').trigger('click')
+    expect(w.find('[data-testid="failure-category-section"]').exists()).toBe(true)
+    expect(w.find('[data-testid="pending-action-row"]').exists()).toBe(true)
+  })
+
+  it('clicking Flag shows pending action row', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
+    await w.find('[data-testid="flag-btn"]').trigger('click')
+    expect(w.find('[data-testid="pending-action-row"]').exists()).toBe(true)
+  })
+
+  it('confirming discard emits discard with null when no category selected', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
+    await w.find('[data-testid="discard-btn"]').trigger('click')
+    await w.find('[data-testid="confirm-pending-btn"]').trigger('click')
+    expect(w.emitted('discard')).toBeTruthy()
+    expect(w.emitted('discard')![0]).toEqual([null])
+  })
+
+  it('confirming discard emits discard with selected category', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
+    await w.find('[data-testid="discard-btn"]').trigger('click')
+    await w.find('[data-testid="category-chip-scoring_artifact"]').trigger('click')
+    await w.find('[data-testid="confirm-pending-btn"]').trigger('click')
+    expect(w.emitted('discard')![0]).toEqual(['scoring_artifact'])
+  })
+
+  it('cancelling pending action hides the pending row', async () => {
+    const w = mount(SftCard, { props: { item: LOW_QUALITY_ITEM } })
+    await w.find('[data-testid="discard-btn"]').trigger('click')
+    await w.find('[data-testid="cancel-pending-btn"]').trigger('click')
+    expect(w.find('[data-testid="pending-action-row"]').exists()).toBe(false)
+  })
 })
diff --git a/web/src/components/SftCard.vue b/web/src/components/SftCard.vue
index f0ac2d1..0a702a3 100644
--- a/web/src/components/SftCard.vue
+++ b/web/src/components/SftCard.vue
@@ -57,21 +57,52 @@
       <button
         data-testid="discard-btn"
         class="btn-discard"
-        @click="$emit('discard')"
+        @click="emitWithCategory('discard')"
       >✕ Discard</button>
       <button
         data-testid="flag-btn"
         class="btn-flag"
-        @click="$emit('flag')"
+        @click="emitWithCategory('flag')"
       >⚑ Flag Model</button>
     </div>
 
+    <!-- Failure category selector (shown when correcting or acting) -->
+    <div
+      v-if="correcting || pendingAction"
+      class="failure-category-section"
+      data-testid="failure-category-section"
+    >
+      <p class="section-label">Failure category <span class="optional-label">(optional)</span></p>
+      <div class="category-chips" role="group" aria-label="Failure category">
+        <button
+          v-for="cat in FAILURE_CATEGORIES"
+          :key="cat.value"
+          type="button"
+          class="category-chip"
+          :class="{ 'category-chip--active': selectedCategory === cat.value }"
+          :aria-pressed="selectedCategory === cat.value || undefined"
+          :data-testid="'category-chip-' + cat.value"
+          @click="toggleCategory(cat.value)"
+        >{{ cat.label }}</button>
+      </div>
+
+      <!-- Pending discard/flag confirm row -->
+      <div v-if="pendingAction" class="pending-action-row" data-testid="pending-action-row">
+        <button class="btn-confirm" @click="confirmPendingAction" data-testid="confirm-pending-btn">
+          Confirm {{ pendingAction }}
+        </button>
+        <button class="btn-cancel-pending" @click="cancelPendingAction" data-testid="cancel-pending-btn">
+          Cancel
+        </button>
+      </div>
+    </div>
+
     <!-- Correction area (shown when correcting = true) -->
     <div v-if="correcting" data-testid="correction-area">
       <SftCorrectionArea
         ref="correctionAreaEl"
         :described-by="'sft-failure-' + item.id"
-        @submit="$emit('submit-correction', $event)"
+        @submit="handleSubmitCorrection"
         @cancel="$emit('cancel-correction')"
       />
     </div>
@@ -80,21 +111,32 @@
 
 <script setup lang="ts">
 import { ref, computed } from 'vue'
-import type { SftQueueItem } from '../stores/sft'
+import type { SftQueueItem, SftFailureCategory } from '../stores/sft'
 import SftCorrectionArea from './SftCorrectionArea.vue'
 
 const props = defineProps<{ item: SftQueueItem; correcting?: boolean }>()
 
 const emit = defineEmits<{
   correct: []
-  discard: []
-  flag: []
-  'submit-correction': [text: string]
+  discard: [category: SftFailureCategory | null]
+  flag: [category: SftFailureCategory | null]
+  'submit-correction': [text: string, category: SftFailureCategory | null]
   'cancel-correction': []
 }>()
 
+const FAILURE_CATEGORIES: { value: SftFailureCategory; label: string }[] = [
+  { value: 'scoring_artifact', label: 'Scoring artifact' },
+  { value: 'style_violation',  label: 'Style violation'  },
+  { value: 'partial_answer',   label: 'Partial answer'   },
+  { value: 'wrong_answer',     label: 'Wrong answer'     },
+  { value: 'format_error',     label: 'Format error'     },
+  { value: 'hallucination',    label: 'Hallucination'    },
+]
+
 const promptExpanded   = ref(false)
 const correctionAreaEl = ref<InstanceType<typeof SftCorrectionArea> | null>(null)
+const selectedCategory = ref<SftFailureCategory | null>(null)
+const pendingAction    = ref<'discard' | 'flag' | null>(null)
 
 const qualityClass = computed(() => {
   const s = props.item.quality_score
@@ -110,8 +152,34 @@ const qualityLabel = computed(() => {
   return 'acceptable'
 })
 
+function toggleCategory(cat: SftFailureCategory) {
+  selectedCategory.value = selectedCategory.value === cat ? null : cat
+}
+
+function emitWithCategory(action: 'discard' | 'flag') {
+  pendingAction.value = action
+}
+
+function confirmPendingAction() {
+  if (!pendingAction.value) return
+  emit(pendingAction.value, selectedCategory.value)
+  pendingAction.value = null
+  selectedCategory.value = null
+}
+
+function cancelPendingAction() {
+  pendingAction.value = null
+}
+
+function handleSubmitCorrection(text: string) {
+  emit('submit-correction', text, selectedCategory.value)
+  selectedCategory.value = null
+}
+
 function resetCorrection() {
   correctionAreaEl.value?.reset()
+  selectedCategory.value = null
+  pendingAction.value = null
 }
 
 defineExpose({ resetCorrection })
@@ -243,4 +311,83 @@ defineExpose({ resetCorrection })
 
 .btn-flag { border-color: var(--color-warning); color: var(--color-warning); }
 .btn-flag:hover { background: color-mix(in srgb, var(--color-warning) 10%, transparent); }
+
+/* ── Failure category selector ─────────────────── */
+.failure-category-section {
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-2);
+}
+
+.optional-label {
+  font-size: 0.75rem;
+  font-weight: 400;
+  color: var(--color-text-muted);
+}
+
+.category-chips {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-2);
+}
+
+.category-chip {
+  padding: var(--space-1) var(--space-3);
+  border-radius: var(--radius-full);
+  border: 1px solid var(--color-border);
+  background: var(--color-surface-alt);
+  color: var(--color-text-muted);
+  font-size: 0.78rem;
+  font-weight: 500;
+  cursor: pointer;
+  transition: background var(--transition), color var(--transition), border-color var(--transition);
+}
+
+.category-chip:hover {
+  border-color: var(--color-accent);
+  color: var(--color-accent);
+  background: var(--color-accent-light);
+}
+
+.category-chip--active {
+  background: var(--color-accent-light);
+  border-color: var(--color-accent);
+  color: var(--color-accent);
+  font-weight: 700;
+}
+
+.pending-action-row {
+  display: flex;
+  gap: var(--space-2);
+  margin-top: var(--space-1);
+}
+
+.btn-confirm {
+  padding: var(--space-1) var(--space-3);
+  border-radius: var(--radius-md);
+  border: 1px solid var(--color-accent);
+  background: var(--color-accent-light);
+  color: var(--color-accent);
+  font-size: 0.85rem;
+  font-weight: 600;
+  cursor: pointer;
+}
+
+.btn-confirm:hover {
+  background: color-mix(in srgb, var(--color-accent) 15%, transparent);
+}
+
+.btn-cancel-pending {
+  padding: var(--space-1) var(--space-3);
+  border-radius: var(--radius-md);
+  border: 1px solid var(--color-border);
+  background: none;
+  color: var(--color-text-muted);
+  font-size: 0.85rem;
+  cursor: pointer;
+}
+
+.btn-cancel-pending:hover {
+  background: var(--color-surface-alt);
+}
 </style>
diff --git a/web/src/stores/sft.ts b/web/src/stores/sft.ts
index 68b765c..a698752 100644
--- a/web/src/stores/sft.ts
+++ b/web/src/stores/sft.ts
@@ -2,6 +2,14 @@
 import { defineStore } from 'pinia'
 import { computed, ref } from 'vue'
 
+export type SftFailureCategory =
+  | 'scoring_artifact'
+  | 'style_violation'
+  | 'partial_answer'
+  | 'wrong_answer'
+  | 'format_error'
+  | 'hallucination'
+
 export interface SftQueueItem {
   id: string
   source: 'cf-orch-benchmark'
@@ -13,6 +21,7 @@ export interface SftQueueItem {
   corrected_response: string | null
   quality_score: number          // 0.0 to 1.0
   failure_reason: string | null
+  failure_category: SftFailureCategory | null
   task_id: string
   task_type: string
   task_name: string
@@ -26,6 +35,7 @@ export interface SftQueueItem {
 export interface SftLastAction {
   type: 'correct' | 'discard' | 'flag'
   item: SftQueueItem
+  failure_category?: SftFailureCategory | null
 }
 
 export const useSftStore = defineStore('sft', () => {
@@ -39,8 +49,12 @@ export const useSftStore = defineStore('sft', () => {
     queue.value.shift()
   }
 
-  function setLastAction(type: SftLastAction['type'], item: SftQueueItem) {
-    lastAction.value = { type, item }
+  function setLastAction(
+    type: SftLastAction['type'],
+    item: SftQueueItem,
+    failure_category?: SftFailureCategory | null,
+  ) {
+    lastAction.value = { type, item, failure_category }
   }
 
   function clearLastAction() {
diff --git a/web/src/views/CorrectionsView.vue b/web/src/views/CorrectionsView.vue
index 3245a86..755b55e 100644
--- a/web/src/views/CorrectionsView.vue
+++ b/web/src/views/CorrectionsView.vue
@@ -36,6 +36,7 @@
           @flag="handleFlag"
           @submit-correction="handleCorrect"
           @cancel-correction="correcting = false"
+          ref="sftCardEl"
         />
       </div>
     </template>
@@ -67,6 +68,7 @@
 <script setup lang="ts">
 import { ref, onMounted } from 'vue'
 import { useSftStore } from '../stores/sft'
+import type { SftFailureCategory } from '../stores/sft'
 import { useSftKeyboard } from '../composables/useSftKeyboard'
 import SftCard from '../components/SftCard.vue'
 
@@ -76,6 +78,7 @@ const apiError   = ref(false)
 const correcting = ref(false)
 const stats      = ref<Record<string, any> | null>(null)
 const exportUrl  = '/api/sft/export'
+const sftCardEl  = ref<InstanceType<typeof SftCard> | null>(null)
 
 useSftKeyboard({
   onCorrect: () => { if (store.current && !correcting.value) correcting.value = true },
@@ -113,19 +116,21 @@ function startCorrection() {
   correcting.value = true
 }
 
-async function handleCorrect(text: string) {
+async function handleCorrect(text: string, category: SftFailureCategory | null = null) {
   if (!store.current) return
   const item = store.current
   correcting.value = false
   try {
+    const body: Record<string, unknown> = { id: item.id, action: 'correct', corrected_response: text }
+    if (category != null) body.failure_category = category
     const res = await fetch('/api/sft/submit', {
       method:  'POST',
       headers: { 'Content-Type': 'application/json' },
-      body:    JSON.stringify({ id: item.id, action: 'correct', corrected_response: text }),
+      body:    JSON.stringify(body),
     })
     if (!res.ok) throw new Error(`HTTP ${res.status}`)
     store.removeCurrentFromQueue()
-    store.setLastAction('correct', item)
+    store.setLastAction('correct', item, category)
     store.totalRemaining = Math.max(0, store.totalRemaining - 1)
     fetchStats()
     if (store.queue.length < 5) fetchBatch()
@@ -134,18 +139,20 @@ async function handleCorrect(text: string) {
   }
 }
 
-async function handleDiscard() {
+async function handleDiscard(category: SftFailureCategory | null = null) {
   if (!store.current) return
   const item = store.current
   try {
+    const body: Record<string, unknown> = { id: item.id, action: 'discard' }
+    if (category != null) body.failure_category = category
     const res = await fetch('/api/sft/submit', {
       method:  'POST',
       headers: { 'Content-Type': 'application/json' },
-      body:    JSON.stringify({ id: item.id, action: 'discard' }),
+      body:    JSON.stringify(body),
     })
     if (!res.ok) throw new Error(`HTTP ${res.status}`)
     store.removeCurrentFromQueue()
-    store.setLastAction('discard', item)
+    store.setLastAction('discard', item, category)
     store.totalRemaining = Math.max(0, store.totalRemaining - 1)
     fetchStats()
     if (store.queue.length < 5) fetchBatch()
@@ -154,18 +161,20 @@ async function handleDiscard() {
   }
 }
 
-async function handleFlag() {
+async function handleFlag(category: SftFailureCategory | null = null) {
   if (!store.current) return
   const item = store.current
   try {
+    const body: Record<string, unknown> = { id: item.id, action: 'flag' }
+    if (category != null) body.failure_category = category
     const res = await fetch('/api/sft/submit', {
       method:  'POST',
       headers: { 'Content-Type': 'application/json' },
-      body:    JSON.stringify({ id: item.id, action: 'flag' }),
+      body:    JSON.stringify(body),
     })
     if (!res.ok) throw new Error(`HTTP ${res.status}`)
     store.removeCurrentFromQueue()
-    store.setLastAction('flag', item)
+    store.setLastAction('flag', item, category)
     store.totalRemaining = Math.max(0, store.totalRemaining - 1)
     fetchStats()
     if (store.queue.length < 5) fetchBatch()