diff --git a/client/src/components/SidePanel/Parameters/Panel.tsx b/client/src/components/SidePanel/Parameters/Panel.tsx
index 7541f4f0e8..0aeb990224 100644
--- a/client/src/components/SidePanel/Parameters/Panel.tsx
+++ b/client/src/components/SidePanel/Parameters/Panel.tsx
@@ -50,8 +50,34 @@ export default function Parameters() {
       .map((param) => (overriddenParamsMap[param.key] as SettingDefinition) ?? param);
   }, [endpointType, endpointsConfig, model, provider]);
 
+  const filteredParameters = useMemo((): SettingDefinition[] => {
+    const allowXHigh = /^gpt-5\\.2/.test(model ?? '');
+
+    return parameters?.map((param) => {
+      if (param?.key !== 'reasoning_effort' || !param.options) {
+        return param;
+      }
+
+      const filteredOptions = allowXHigh
+        ? param.options
+        : param.options.filter((option) => option !== 'xhigh');
+
+      const filteredEnumMappings = param.enumMappings
+        ? Object.fromEntries(
+            Object.entries(param.enumMappings).filter(([key]) => allowXHigh || key !== 'xhigh'),
+          )
+        : undefined;
+
+      return {
+        ...param,
+        options: filteredOptions,
+        enumMappings: filteredEnumMappings,
+      };
+    });
+  }, [parameters, model]);
+
   useEffect(() => {
-    if (!parameters) {
+    if (!filteredParameters) {
       return;
     }
 
@@ -65,7 +91,7 @@ export default function Parameters() {
     //   }),
     // );
     const paramKeys = new Set(
-      parameters.filter((setting) => setting != null).map((setting) => setting.key),
+      filteredParameters.filter((setting) => setting != null).map((setting) => setting.key),
     );
     setConversation((prev) => {
       if (!prev) {
@@ -76,6 +102,13 @@ export default function Parameters() {
 
       const conversationKeys = Object.keys(updatedConversation);
       const updatedKeys: string[] = [];
+
+      const allowXHigh = /^gpt-5\\.2/.test(model ?? '');
+      if (!allowXHigh && updatedConversation.reasoning_effort === 'xhigh') {
+        updatedKeys.push('reasoning_effort');
+        delete updatedConversation.reasoning_effort;
+      }
+
       conversationKeys.forEach((key) => {
         // const defaultValue = defaultValueMap.get(key);
         // if (paramKeys.has(key) && defaultValue != null && prev[key] != null) {
@@ -102,7 +135,7 @@ export default function Parameters() {
 
       return updatedConversation;
     });
-  }, [parameters, setConversation]);
+  }, [filteredParameters, setConversation, model]);
 
   const resetParameters = useCallback(() => {
     setConversation((prev) => {
@@ -137,7 +170,7 @@ export default function Parameters() {
     setIsDialogOpen(true);
   }, [conversation]);
 
-  if (!parameters) {
+  if (!filteredParameters) {
     return null;
   }
 
@@ -147,7 +180,7 @@ export default function Parameters() {
         {' '}
         {/* This is the parent element containing all settings */}
         {/* Below is an example of an applied dynamic setting, each be contained by a div with the column span specified */}
-        {parameters.map((setting) => {
+        {filteredParameters.map((setting) => {
           const Component = componentMapping[setting.component];
           if (!Component) {
             return null;
diff --git a/client/src/locales/en/translation.json b/client/src/locales/en/translation.json
index a82e931072..7ee49a2a3a 100644
--- a/client/src/locales/en/translation.json
+++ b/client/src/locales/en/translation.json
@@ -971,6 +971,7 @@
   "com_ui_hide_password": "Hide password",
   "com_ui_hide_qr": "Hide QR Code",
   "com_ui_high": "High",
+  "com_ui_extra_high": "Extra High",
   "com_ui_host": "Host",
   "com_ui_icon": "Icon",
   "com_ui_idea": "Ideas",
diff --git a/packages/api/src/endpoints/openai/llm.spec.ts b/packages/api/src/endpoints/openai/llm.spec.ts
index a4eb7c78e3..09047ba93b 100644
--- a/packages/api/src/endpoints/openai/llm.spec.ts
+++ b/packages/api/src/endpoints/openai/llm.spec.ts
@@ -210,6 +210,32 @@ describe('getOpenAILLMConfig', () => {
       });
     });
 
+    it('should allow xhigh reasoning_effort for gpt-5.2 models', () => {
+      const result = getOpenAILLMConfig({
+        apiKey: 'test-api-key',
+        streaming: true,
+        modelOptions: {
+          model: 'gpt-5.2-pro',
+          reasoning_effort: ReasoningEffort.xhigh,
+        },
+      });
+
+      expect(result.llmConfig).toHaveProperty('reasoning_effort', ReasoningEffort.xhigh);
+    });
+
+    it('should drop xhigh reasoning_effort for non-gpt-5.2 models', () => {
+      const result = getOpenAILLMConfig({
+        apiKey: 'test-api-key',
+        streaming: true,
+        modelOptions: {
+          model: 'gpt-5-pro',
+          reasoning_effort: ReasoningEffort.xhigh,
+        },
+      });
+
+      expect(result.llmConfig).not.toHaveProperty('reasoning_effort');
+    });
+
     it('should NOT exclude parameters for gpt-5-chat (it supports sampling params)', () => {
       const result = getOpenAILLMConfig({
         apiKey: 'test-api-key',
diff --git a/packages/api/src/endpoints/openai/llm.ts b/packages/api/src/endpoints/openai/llm.ts
index c88122310a..e50d29ed3e 100644
--- a/packages/api/src/endpoints/openai/llm.ts
+++ b/packages/api/src/endpoints/openai/llm.ts
@@ -220,20 +220,24 @@ export function getOpenAILLMConfig({
     llmConfig.include_reasoning = true;
   }
 
+  const allowXHigh = modelOptions.model ? /^gpt-5\\.2/.test(String(modelOptions.model)) : false;
+  const sanitizedReasoningEffort =
+    reasoning_effort === 'xhigh' && !allowXHigh ? undefined : reasoning_effort;
+
   if (
-    hasReasoningParams({ reasoning_effort, reasoning_summary }) &&
+    hasReasoningParams({ reasoning_effort: sanitizedReasoningEffort, reasoning_summary }) &&
     (llmConfig.useResponsesApi === true ||
       (endpoint !== EModelEndpoint.openAI && endpoint !== EModelEndpoint.azureOpenAI))
   ) {
     llmConfig.reasoning = removeNullishValues(
       {
-        effort: reasoning_effort,
+        effort: sanitizedReasoningEffort,
         summary: reasoning_summary,
       },
       true,
     ) as OpenAI.Reasoning;
-  } else if (hasReasoningParams({ reasoning_effort })) {
-    llmConfig.reasoning_effort = reasoning_effort;
+  } else if (hasReasoningParams({ reasoning_effort: sanitizedReasoningEffort })) {
+    llmConfig.reasoning_effort = sanitizedReasoningEffort;
   }
 
   if (llmConfig.max_tokens != null) {
diff --git a/packages/data-provider/src/parameterSettings.ts b/packages/data-provider/src/parameterSettings.ts
index b3ed86b0f3..ec92e43837 100644
--- a/packages/data-provider/src/parameterSettings.ts
+++ b/packages/data-provider/src/parameterSettings.ts
@@ -239,6 +239,7 @@ const openAIParams: Record<string, SettingDefinition> = {
       ReasoningEffort.low,
       ReasoningEffort.medium,
       ReasoningEffort.high,
+      ReasoningEffort.xhigh,
     ],
     enumMappings: {
       [ReasoningEffort.unset]: 'com_ui_auto',
@@ -247,6 +248,7 @@ const openAIParams: Record<string, SettingDefinition> = {
       [ReasoningEffort.low]: 'com_ui_low',
       [ReasoningEffort.medium]: 'com_ui_medium',
       [ReasoningEffort.high]: 'com_ui_high',
+      [ReasoningEffort.xhigh]: 'com_ui_extra_high',
     },
     optionType: 'model',
     columnSpan: 4,
diff --git a/packages/data-provider/src/schemas.ts b/packages/data-provider/src/schemas.ts
index ecf0a925fc..53410af871 100644
--- a/packages/data-provider/src/schemas.ts
+++ b/packages/data-provider/src/schemas.ts
@@ -169,6 +169,7 @@ export enum ReasoningEffort {
   low = 'low',
   medium = 'medium',
   high = 'high',
+  xhigh = 'xhigh',
 }
 
 export enum ReasoningSummary {