diff --git a/backend/pkg/providers/pconfig/config.go b/backend/pkg/providers/pconfig/config.go
index ce722c40..ddb27975 100644
--- a/backend/pkg/providers/pconfig/config.go
+++ b/backend/pkg/providers/pconfig/config.go
@@ -724,7 +724,7 @@ func (ac *AgentConfig) BuildOptions() []llms.CallOption {
 			}
 		default:
 			switch ac.Reasoning.Effort {
-			case llms.ReasoningLow, llms.ReasoningMedium, llms.ReasoningHigh:
+			case llms.ReasoningLow, llms.ReasoningMedium, llms.ReasoningHigh, llms.ReasoningXHigh, llms.ReasoningMax:
 				options = append(options, llms.WithReasoning(ac.Reasoning.Effort, 0))
 			}
 		}
diff --git a/backend/pkg/providers/pconfig/reasoning_effort_test.go b/backend/pkg/providers/pconfig/reasoning_effort_test.go
new file mode 100644
index 00000000..54157bb2
--- /dev/null
+++ b/backend/pkg/providers/pconfig/reasoning_effort_test.go
@@ -0,0 +1,37 @@
+package pconfig
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/vxcontrol/langchaingo/llms"
+	"gopkg.in/yaml.v3"
+)
+
+func TestReasoningConfig_GetEffortPreservesXHighAndMax(t *testing.T) {
+	for _, effort := range []llms.ReasoningEffort{llms.ReasoningXHigh, llms.ReasoningMax} {
+		rc := llms.ReasoningConfig{Effort: effort}
+		if got := rc.GetEffort(8192); got != effort {
+			t.Errorf("GetEffort(effort=%q) = %q, want %q: the xhigh/max clamp must stay removed so OpenAI-compatible reasoning_effort carries the real level", effort, got, effort)
+		}
+	}
+}
+
+func TestProviderConfig_EmitsTopReasoningEffortOnEffortPath(t *testing.T) {
+	for _, effort := range []string{"low", "medium", "high", "xhigh", "max"} {
+		t.Run(effort, func(t *testing.T) {
+			var ac AgentConfig
+			require.NoError(t, yaml.Unmarshal([]byte("model: gpt-5.5\nreasoning:\n  effort: "+effort+"\n"), &ac))
+
+			pc := &ProviderConfig{Simple: &ac}
+			var applied llms.CallOptions
+			for _, opt := range pc.GetOptionsForType(OptionsTypeSimple) {
+				opt(&applied)
+			}
+
+			require.NotNil(t, applied.Reasoning, "effort %q must emit a reasoning option on the non-adaptive path", effort)
+			assert.Equal(t, llms.ReasoningEffort(effort), applied.Reasoning.Effort, "the configured effort must reach the call options unchanged")
+		})
+	}
+}