diff --git a/src/core/doctor-categories.ts b/src/core/doctor-categories.ts
index e445bfeea..9e8f5b24c 100644
--- a/src/core/doctor-categories.ts
+++ b/src/core/doctor-categories.ts
@@ -103,6 +103,7 @@ export const BRAIN_CHECK_NAMES: ReadonlySet<string> = new Set([
   'sync_failures',
   'sync_freshness',
   'takes_weight_grid',
+  'timeline_coverage',
   'unified_multimodal_coverage',
   'voice_gate_health',
 ]);
diff --git a/test/doctor-categories.test.ts b/test/doctor-categories.test.ts
index b6bbf3b8f..ea4e89de6 100644
--- a/test/doctor-categories.test.ts
+++ b/test/doctor-categories.test.ts
@@ -124,6 +124,10 @@ describe('categorizeCheck', () => {
     expect(categorizeCheck('sync_freshness')).toBe('brain');
   });
 
+  test('timeline_coverage (emitted by onboard/checks.ts, not doctor.ts) is brain, not meta fallthrough (#2817)', () => {
+    expect(categorizeCheck('timeline_coverage')).toBe('brain');
+  });
+
   test('returns the right category for a known skill name', () => {
     expect(categorizeCheck('resolver_health')).toBe('skill');
     expect(categorizeCheck('skill_conformance')).toBe('skill');