fix(google-genai): Support larger range of temperatures for Gemini models (#7703)

Co-authored-by: Jacob Lee <[email protected]>

Author: afirstenberg

libs/langchain-google-genai/src/chat_models.ts

@@ -101,7 +101,7 @@ export interface GoogleGenerativeAIChatInput
   /**
    * Controls the randomness of the output.
    *
-   * Values can range from [0.0,1.0], inclusive. A value closer to 1.0
+   * Values can range from [0.0,2.0], inclusive. A value closer to 2.0
    * will produce responses that are more varied and creative, while
    * a value closer to 0.0 will typically result in less surprising
    * responses from the model.
@@ -644,8 +644,8 @@ export class ChatGoogleGenerativeAI
     }
 
     this.temperature = fields?.temperature ?? this.temperature;
-    if (this.temperature && (this.temperature < 0 || this.temperature > 1)) {
-      throw new Error("`temperature` must be in the range of [0.0,1.0]");
+    if (this.temperature && (this.temperature < 0 || this.temperature > 2)) {
+      throw new Error("`temperature` must be in the range of [0.0,2.0]");
     }
 
     this.topP = fields?.topP ?? this.topP;

libs/langchain-google-genai/src/tests/chat_models.test.ts

@@ -28,7 +28,7 @@ function extractKeys(obj: Record<string, any>, keys: string[] = []) {
   return keys;
 }
 
-test("Google AI - `temperature` must be in range [0.0,1.0]", async () => {
+test("Google AI - `temperature` must be in range [0.0,2.0]", async () => {
   expect(
     () =>
       new ChatGoogleGenerativeAI({
@@ -38,7 +38,7 @@ test("Google AI - `temperature` must be in range [0.0,1.0]", async () => {
   expect(
     () =>
       new ChatGoogleGenerativeAI({
-        temperature: 1.1,
+        temperature: 2.1,
       })
   ).toThrow();
 });