diff --git a/src/main/services/telemetryEvents.ts b/src/main/services/telemetryEvents.ts
index 94e3c5f..66471e7 100644
--- a/src/main/services/telemetryEvents.ts
+++ b/src/main/services/telemetryEvents.ts
@@ -50,6 +50,15 @@ const AiRetryManualPayload = z.object({
   failedCount: z.number().int().positive()
 }).strict();
 
+const TagVocabHitPayload = z.object({
+  tagId: z.number().int().positive(),
+  vocabSize: z.number().int().nonnegative()
+}).strict();
+
+const TagVocabMissPayload = z.object({
+  vocabSize: z.number().int().nonnegative()
+}).strict();
+
 export const TelemetryEventSchema = z.discriminatedUnion('kind', [
   z.object({ ts: z.string(), kind: z.literal('capture'), payload: CapturePayload }).strict(),
   z.object({ ts: z.string(), kind: z.literal('ai_succeeded'), payload: AiSucceededPayload }).strict(),
@@ -63,7 +72,9 @@ export const TelemetryEventSchema = z.discriminatedUnion('kind', [
   z.object({ ts: z.string(), kind: z.literal('ollama_unreachable'), payload: OllamaUnreachablePayload }).strict(),
   z.object({ ts: z.string(), kind: z.literal('ollama_recovered'), payload: OllamaRecoveredPayload }).strict(),
   z.object({ ts: z.string(), kind: z.literal('ollama_recheck_manual'), payload: EmptyPayload }).strict(),
-  z.object({ ts: z.string(), kind: z.literal('ai_retry_manual'), payload: AiRetryManualPayload }).strict()
+  z.object({ ts: z.string(), kind: z.literal('ai_retry_manual'), payload: AiRetryManualPayload }).strict(),
+  z.object({ ts: z.string(), kind: z.literal('tag_vocab_hit'), payload: TagVocabHitPayload }).strict(),
+  z.object({ ts: z.string(), kind: z.literal('tag_vocab_miss'), payload: TagVocabMissPayload }).strict()
 ]);
 
 export type TelemetryEvent = z.infer<typeof TelemetryEventSchema>;
diff --git a/tests/unit/telemetryEvents.test.ts b/tests/unit/telemetryEvents.test.ts
index f41bdef..5266346 100644
--- a/tests/unit/telemetryEvents.test.ts
+++ b/tests/unit/telemetryEvents.test.ts
@@ -278,3 +278,31 @@ describe('ai_retry_manual event', () => {
     })).toThrow();
   });
 });
+
+describe('validateEvent — tag vocab', () => {
+  it('accepts tag_vocab_hit event', () => {
+    const e = validateEvent({
+      ts: '2026-05-02T00:00:00.000Z',
+      kind: 'tag_vocab_hit',
+      payload: { tagId: 42, vocabSize: 17 }
+    });
+    expect(e.kind).toBe('tag_vocab_hit');
+  });
+
+  it('accepts tag_vocab_miss event without tagId', () => {
+    const e = validateEvent({
+      ts: '2026-05-02T00:00:00.000Z',
+      kind: 'tag_vocab_miss',
+      payload: { vocabSize: 17 }
+    });
+    expect(e.kind).toBe('tag_vocab_miss');
+  });
+
+  it('rejects tag_vocab_hit with extra field (privacy invariant)', () => {
+    expect(() => validateEvent({
+      ts: '2026-05-02T00:00:00.000Z',
+      kind: 'tag_vocab_hit',
+      payload: { tagId: 42, vocabSize: 17, tagName: 'leak' }
+    })).toThrow();
+  });
+});