diff --git a/backend/tests/integration/test_api_v5_lineage.py b/backend/tests/integration/test_api_v5_lineage.py
index 98a9ef2..2bf1aa3 100644
--- a/backend/tests/integration/test_api_v5_lineage.py
+++ b/backend/tests/integration/test_api_v5_lineage.py
@@ -65,6 +65,16 @@ def _fork(client, space_id, checkpoint_id, branch_name="", provider="", model=""
     return r
 
 
+def _add_note(client, checkpoint_id, text, author="founder", kind="note"):
+    r = client.post(f"/api/v5/checkpoint/{checkpoint_id}/notes", json={
+        "text": text,
+        "author": author,
+        "kind": kind,
+    })
+    assert r.status_code == 201, r.text
+    return r.json()
+
+
 # ── Fork tests ────────────────────────────────────────────────────────────────
 
 def test_fork_creates_new_session(client):
@@ -357,6 +367,29 @@ def test_lineage_checkpoint_includes_author_agent(client):
     )
 
 
+def test_lineage_checkpoint_includes_note_summary(client):
+    """note_count and note_kinds round-trip through the lineage endpoint."""
+    repo_id = _create_repo(client, "Lineage Note Summary")
+    session_id = _create_session(client, repo_id)
+
+    mixed = _commit(client, repo_id, session_id, message="Checkpoint with mixed notes")
+    plain = _commit(client, repo_id, session_id, message="Checkpoint without notes")
+
+    _add_note(client, mixed["id"], "Milestone note", kind="milestone")
+    _add_note(client, mixed["id"], "Noise note", kind="noise")
+    _add_note(client, mixed["id"], "Plain note", kind="note")
+
+    r = client.get(f"/api/v5/lineage/spaces/{repo_id}")
+    assert r.status_code == 200, r.text
+    checkpoints = r.json()["checkpoints"]
+    by_id = {c["id"]: c for c in checkpoints}
+
+    assert by_id[mixed["id"]]["note_count"] == 3
+    assert by_id[mixed["id"]]["note_kinds"] == ["milestone", "noise", "note"]
+    assert by_id[plain["id"]]["note_count"] == 0
+    assert by_id[plain["id"]]["note_kinds"] == []
+
+
 # ── Compare tests ─────────────────────────────────────────────────────────────
 
 def test_compare_same_checkpoint(client):
diff --git a/frontend/src/pages/LineagePage.tsx b/frontend/src/pages/LineagePage.tsx
index cb3c37f..1ab0159 100644
--- a/frontend/src/pages/LineagePage.tsx
+++ b/frontend/src/pages/LineagePage.tsx
@@ -38,6 +38,42 @@ function fmt(d: string) {
   });
 }
 
+function getCheckpointNoteBadge(checkpoint: CheckpointNode) {
+  const kinds = checkpoint.note_kinds ?? [];
+  const plural = checkpoint.note_count !== 1 ? 's' : '';
+  const kindSummary = kinds.length > 0 ? kinds.join(' + ') : 'note';
+
+  if (kinds.length > 1) {
+    return {
+      label: 'mix',
+      title: `${checkpoint.note_count} note${plural} · ${kindSummary}`,
+      className: 'text-sky-300 bg-sky-950/30 border border-sky-500/30',
+    };
+  }
+
+  if (kinds.includes('milestone')) {
+    return {
+      label: '★',
+      title: `${checkpoint.note_count} note${plural} · milestone`,
+      className: 'text-amber-400 bg-amber-900/20 border border-amber-500/30',
+    };
+  }
+
+  if (kinds.includes('noise')) {
+    return {
+      label: '◌',
+      title: `${checkpoint.note_count} note${plural} · noise`,
+      className: 'text-gray-500 bg-gray-800/30 border border-gray-700',
+    };
+  }
+
+  return {
+    label: '●',
+    title: `${checkpoint.note_count} note${plural} · note`,
+    className: 'text-gray-400 bg-gray-800/30 border border-gray-700',
+  };
+}
+
 // ── Compare Panel ─────────────────────────────────────────────────────────────
 
 function ComparePanel({
@@ -296,6 +332,7 @@ function CheckpointCard({
   onFork: (c: CheckpointNode) => void;
 }) {
   const [expanded, setExpanded] = useState(false);
+  const noteBadge = checkpoint.note_count > 0 ? getCheckpointNoteBadge(checkpoint) : null;
 
   return (
     <div
@@ -320,19 +357,12 @@ function CheckpointCard({
               </span>
             )}
             <span className="text-[10px] text-gray-600">{fmt(checkpoint.created_at)}</span>
-            {checkpoint.note_count > 0 && (
+            {noteBadge && (
               <span
-                className={`text-[9px] font-medium px-1 py-px rounded ${
-                  checkpoint.note_kinds.includes('milestone')
-                    ? 'text-amber-400 bg-amber-900/20 border border-amber-500/30'
-                    : checkpoint.note_kinds.includes('noise')
-                      ? 'text-gray-500 bg-gray-800/30 border border-gray-700'
-                      : 'text-gray-400 bg-gray-800/30 border border-gray-700'
-                }`}
-                title={`${checkpoint.note_count} note${checkpoint.note_count !== 1 ? 's' : ''}`}
+                className={`text-[9px] font-medium px-1 py-px rounded ${noteBadge.className}`}
+                title={noteBadge.title}
               >
-                {checkpoint.note_kinds.includes('milestone') ? '★' :
-                 checkpoint.note_kinds.includes('noise') ? '◌' : '●'}
+                {noteBadge.label}
               </span>
             )}
           </div>