diff --git a/backend/python/sglang/backend.py b/backend/python/sglang/backend.py
index bb853af9a..bacb40159 100644
--- a/backend/python/sglang/backend.py
+++ b/backend/python/sglang/backend.py
@@ -207,6 +207,10 @@ class BackendServicer(backend_pb2_grpc.BackendServicer):
             return self.effort_budgets[effort]
         return self.thinking_budget
 
+    def _configured_budget(self) -> Optional[int]:
+        """Any budget configured for this model (fixed or per effort), for the load-time warning."""
+        return self.thinking_budget or max((self.effort_budgets or {}).values(), default=None)
+
     @staticmethod
     def _strict_thinking_warning(thinking_budget: Optional[int], engine_kwargs: dict) -> Optional[str]:
         """sglang only enforces the budget with enable_strict_thinking on; without
@@ -389,9 +393,7 @@ class BackendServicer(backend_pb2_grpc.BackendServicer):
             print(f"engine_args error: {err}", file=sys.stderr)
             return backend_pb2.Result(success=False, message=str(err))
 
-        warning = self._strict_thinking_warning(
-            self.thinking_budget or max((self.effort_budgets or {}).values(), default=None), engine_kwargs
-        )
+        warning = self._strict_thinking_warning(self._configured_budget(), engine_kwargs)
         if warning:
             print(warning, file=sys.stderr)
 
diff --git a/backend/python/sglang/test.py b/backend/python/sglang/test.py
index c04c2156f..05c967a0f 100644
--- a/backend/python/sglang/test.py
+++ b/backend/python/sglang/test.py
@@ -402,6 +402,16 @@ class TestSglangHelpers(unittest.TestCase):
         self.assertIsNone(servicer._strict_thinking_warning(512, {"enable_strict_thinking": True}))
         self.assertIsNone(servicer._strict_thinking_warning(None, {}))
 
+    def test_warns_when_only_effort_budgets_are_set(self):
+        """A model with effort_budgets but no thinking_budget still needs strict thinking."""
+        servicer = self._servicer()
+        servicer.thinking_budget = None
+        servicer.effort_budgets = {"low": 256, "max": 16384}
+        self.assertEqual(servicer._configured_budget(), 16384)
+        self.assertIn("enable_strict_thinking", servicer._strict_thinking_warning(servicer._configured_budget(), {}))
+        servicer.effort_budgets = {}
+        self.assertIsNone(servicer._configured_budget())
+
     def test_explicit_zero_temperature_and_seed_are_preserved(self):
         """Temperature=0 is greedy decoding and 0 is a valid seed — neither is
         an unset value. A dropped seed turns a reproducible request random."""
diff --git a/core/config/reasoning_effort_test.go b/core/config/reasoning_effort_test.go
index c3a341eb2..4cf7362d2 100644
--- a/core/config/reasoning_effort_test.go
+++ b/core/config/reasoning_effort_test.go
@@ -46,11 +46,13 @@ var _ = Describe("ModelConfig.ApplyReasoningEffort", func() {
 	})
 
 	It("does not let a level override an operator's config-level disable", func() {
-		disabled := true
-		c := &config.ModelConfig{}
-		c.ReasoningConfig.DisableReasoning = &disabled
-		c.ApplyReasoningEffort("high")
-		Expect(*c.ReasoningConfig.DisableReasoning).To(BeTrue())
+		for _, level := range []string{"high", "xhigh", "max"} {
+			disabled := true
+			c := &config.ModelConfig{}
+			c.ReasoningConfig.DisableReasoning = &disabled
+			c.ApplyReasoningEffort(level)
+			Expect(*c.ReasoningConfig.DisableReasoning).To(BeTrue(), level)
+		}
 	})
 
 	It("is a no-op on the toggle when no effort is set anywhere", func() {