diff --git a/src/global.d.ts b/src/global.d.ts
index 6a84c80..33ab90a 100644
--- a/src/global.d.ts
+++ b/src/global.d.ts
@@ -1,6 +1,12 @@
 export type ChromeAISessionAvailable = 'no' | 'after-download' | 'readily';
 
-export interface ChromeAISessionOptions {
+export interface ChromeAIModelInfo {
+  defaultTemperature: number;
+  defaultTopK: number;
+  maxTopK: number;
+}
+
+export interface ChromeAISessionOptions extends Record<string, any> {
   temperature?: number;
   topK?: number;
 }
@@ -13,7 +19,7 @@ export interface ChromeAISession {
 
 export interface ChromePromptAPI {
   canCreateTextSession: () => Promise<ChromeAISessionAvailable>;
-  defaultTextSessionOptions: () => Promise<ChromeAISessionOptions>;
+  textModelInfo: () => Promise<ChromeAIModelInfo>;
   createTextSession: (
     options?: ChromeAISessionOptions
   ) => Promise<ChromeAISession>;
diff --git a/src/language-model.ts b/src/language-model.ts
index a768edc..dc94eeb 100644
--- a/src/language-model.ts
+++ b/src/language-model.ts
@@ -24,33 +24,7 @@ export type ChromeAIChatModelId = 'text';
 
 export interface ChromeAIChatSettings extends Record<string, unknown> {
   temperature?: number;
-  /**
-   * Optional. The maximum number of tokens to consider when sampling.
-   *
-   * Models use nucleus sampling or combined Top-k and nucleus sampling.
-   * Top-k sampling considers the set of topK most probable tokens.
-   * Models running with nucleus sampling don't allow topK setting.
-   */
   topK?: number;
-
-  /**
-   * Optional. A list of unique safety settings for blocking unsafe content.
-   * @note this is not working yet
-   */
-  safetySettings?: Array<{
-    category:
-      | 'HARM_CATEGORY_HATE_SPEECH'
-      | 'HARM_CATEGORY_DANGEROUS_CONTENT'
-      | 'HARM_CATEGORY_HARASSMENT'
-      | 'HARM_CATEGORY_SEXUALLY_EXPLICIT';
-
-    threshold:
-      | 'HARM_BLOCK_THRESHOLD_UNSPECIFIED'
-      | 'BLOCK_LOW_AND_ABOVE'
-      | 'BLOCK_MEDIUM_AND_ABOVE'
-      | 'BLOCK_ONLY_HIGH'
-      | 'BLOCK_NONE';
-  }>;
 }
 
 function getStringContent(
@@ -105,8 +79,13 @@ export class ChromeAIChatLanguageModel implements LanguageModelV1 {
       throw new LoadSettingError({ message: 'Built-in model not ready' });
     }
 
-    const defaultOptions = await ai.defaultTextSessionOptions();
-    this.options = { ...defaultOptions, ...this.options, ...options };
+    const defaultOptions = await ai.textModelInfo();
+    this.options = {
+      temperature: defaultOptions.defaultTemperature,
+      topK: defaultOptions.defaultTopK,
+      ...this.options,
+      ...options,
+    };
 
     this.session = await ai.createTextSession(this.options);
 
diff --git a/src/polyfill/session.ts b/src/polyfill/session.ts
index 42511e8..ce8bedb 100644
--- a/src/polyfill/session.ts
+++ b/src/polyfill/session.ts
@@ -1,5 +1,6 @@
 import { LlmInference, ProgressListener } from '@mediapipe/tasks-genai';
 import {
+  ChromeAIModelInfo,
   ChromeAISession,
   ChromeAISessionAvailable,
   ChromeAISessionOptions,
@@ -87,16 +88,17 @@ export class PolyfillChromeAI implements ChromePromptAPI {
     return isModelAssetBufferReady ? 'readily' : 'after-download';
   };
 
-  public defaultTextSessionOptions =
-    async (): Promise<ChromeAISessionOptions> => ({
-      temperature: 0.8,
-      topK: 3,
-    });
+  public textModelInfo = async (): Promise<ChromeAIModelInfo> => ({
+    defaultTemperature: 0.8,
+    defaultTopK: 3,
+    maxTopK: 128,
+  });
 
   public createTextSession = async (
     options?: ChromeAISessionOptions
   ): Promise<ChromeAISession> => {
-    const argv = options ?? (await this.defaultTextSessionOptions());
+    const defaultParams = await this.textModelInfo();
+    const argv = options ?? { temperature: 0.8, topK: 3 };
     const llm = await LlmInference.createFromOptions(
       {
         wasmLoaderPath: this.aiOptions.wasmLoaderPath!,