diff --git a/src/hyperping/models/_oncall_models.py b/src/hyperping/models/_oncall_models.py
index d497058..41771e0 100644
--- a/src/hyperping/models/_oncall_models.py
+++ b/src/hyperping/models/_oncall_models.py
@@ -6,11 +6,22 @@
 
 
 class OnCallSchedule(BaseModel):
-    """On-call rotation schedule."""
+    """On-call rotation schedule.
+
+    .. note::
+        This model has not been validated against a real API response. Neither
+        the production nor the test account had any on-call schedules configured
+        as of 2026-06-13 (re-probed via MCP). The declared fields are inferred
+        from the MCP tool description. Additional fields (rotation config,
+        linked escalation policies) may exist in the actual response and will
+        land in ``model_extra`` due to ``extra="allow"``. Re-run the MCP probe
+        after creating at least one schedule and reconcile this model against
+        the real response shape (ticket #333911).
+    """
 
     model_config = ConfigDict(extra="allow", populate_by_name=True, frozen=True)
 
-    uuid: str = Field(..., description="Schedule UUID")
+    uuid: str = Field(..., description="Schedule UUID (format: \"sch_...\")")
     name: str = Field(..., description="Schedule name")
     current_on_call: str | None = Field(
         default=None, alias="currentOnCall", description="Current on-call person"