diff --git a/openapi.yaml b/openapi.yaml
index a29be73..594781a 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -544,7 +544,7 @@ components:
           minLength: 1
         note:
           type: string
-          maxLength: 500
+          description: Optional. Stored after trim, and the trimmed value must be 500 characters or fewer.
 
     AdminOverrideBody:
       type: object
diff --git a/tests/shared/test_portal_ops.py b/tests/shared/test_portal_ops.py
index 3eda8f2..441e65f 100644
--- a/tests/shared/test_portal_ops.py
+++ b/tests/shared/test_portal_ops.py
@@ -105,6 +105,14 @@ def test_swap_stores_returns_and_dms_note(schedule, seed, quiet_slack, monkeypat
     assert calls[0][1]["note"] == "Family commitment"
 
 
+def test_swap_accepts_note_that_trims_to_500(schedule, seed, quiet_slack):
+    employee = _alice(schedule, seed)
+    seed.override("2026-06-12", "114", "Alice")
+    with freezegun.freeze_time("2026-06-08 12:00:00-04:00"):
+        swap(schedule, employee, "2026-06-12", "115", "night", note=f" {'a' * 500} ")
+    assert schedule.get_swap("2026-06-12", "night")["note"] == "a" * 500
+
+
 def test_swap_omits_blank_note(schedule, seed, quiet_slack):
     employee = _alice(schedule, seed)
     seed.override("2026-06-12", "114", "Alice")