fix: prevent gemini-3-pro-preview from using Google Search grounding

- Added supportsGrounding capability flag to ModelInfo type
- Set supportsGrounding to false for gemini-3-pro-preview
- Set supportsGrounding to true for all other Gemini models
- Updated GeminiHandler to check supportsGrounding before enabling Google Search
- Added tests to verify the fix

Fixes #9520

packages/types/src/model.ts

@@ -109,6 +109,8 @@ export const modelInfoSchema = z.object({
 	isFree: z.boolean().optional(),
 	// Flag to indicate if the model supports native tool calling (OpenAI-style function calling)
 	supportsNativeTools: z.boolean().optional(),
+	// Flag to indicate if the model supports Google Search grounding
+	supportsGrounding: z.boolean().optional(),
 	// Default tool protocol preferred by this model (if not specified, falls back to capability/provider defaults)
 	defaultToolProtocol: z.enum(["xml", "native"]).optional(),
 	/**

packages/types/src/providers/gemini.ts

@@ -12,6 +12,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: false, // Does not support Google Search grounding
 		supportsReasoningEffort: ["low", "high"],
 		reasoningEffort: "low",
 		supportsTemperature: true,
@@ -38,6 +39,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 2.5, // This is the pricing for prompts above 200k tokens.
 		outputPrice: 15,
 		cacheReadsPrice: 0.625,
@@ -66,6 +68,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 2.5, // This is the pricing for prompts above 200k tokens.
 		outputPrice: 15,
 		cacheReadsPrice: 0.625,
@@ -93,6 +96,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 2.5, // This is the pricing for prompts above 200k tokens.
 		outputPrice: 15,
 		cacheReadsPrice: 0.625,
@@ -118,6 +122,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 2.5, // This is the pricing for prompts above 200k tokens.
 		outputPrice: 15,
 		cacheReadsPrice: 0.625,
@@ -147,6 +152,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 0.3,
 		outputPrice: 2.5,
 		cacheReadsPrice: 0.075,
@@ -160,6 +166,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 0.3,
 		outputPrice: 2.5,
 		cacheReadsPrice: 0.075,
@@ -173,6 +180,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 0.3,
 		outputPrice: 2.5,
 		cacheReadsPrice: 0.075,
@@ -188,6 +196,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 0.1,
 		outputPrice: 0.4,
 		cacheReadsPrice: 0.025,
@@ -201,6 +210,7 @@ export const geminiModels = {
 		supportsImages: true,
 		supportsNativeTools: true,
 		supportsPromptCache: true,
+		supportsGrounding: true,
 		inputPrice: 0.1,
 		outputPrice: 0.4,
 		cacheReadsPrice: 0.025,

src/api/providers/__tests__/gemini-handler.spec.ts

@@ -19,6 +19,40 @@ describe("GeminiHandler backend support", () => {
 		expect(config.tools).toEqual([{ urlContext: {} }, { googleSearch: {} }])
 	})
 
+	it("should not enable Google Search for gemini-3-pro-preview even when enableGrounding is true", async () => {
+		const options = {
+			apiProvider: "gemini",
+			apiModelId: "gemini-3-pro-preview",
+			enableUrlContext: false,
+			enableGrounding: true,
+		} as ApiHandlerOptions
+		const handler = new GeminiHandler(options)
+		const stub = vi.fn().mockReturnValue((async function* () {})())
+		// @ts-ignore access private client
+		handler["client"].models.generateContentStream = stub
+		await handler.createMessage("instr", [] as any).next()
+		const config = stub.mock.calls[0][0].config
+		// Should not include googleSearch since model doesn't support it
+		expect(config.tools).toBeUndefined()
+	})
+
+	it("should enable Google Search for models that support grounding", async () => {
+		const options = {
+			apiProvider: "gemini",
+			apiModelId: "gemini-2.5-pro",
+			enableUrlContext: false,
+			enableGrounding: true,
+		} as ApiHandlerOptions
+		const handler = new GeminiHandler(options)
+		const stub = vi.fn().mockReturnValue((async function* () {})())
+		// @ts-ignore access private client
+		handler["client"].models.generateContentStream = stub
+		await handler.createMessage("instr", [] as any).next()
+		const config = stub.mock.calls[0][0].config
+		// Should include googleSearch for models that support it
+		expect(config.tools).toEqual([{ googleSearch: {} }])
+	})
+
 	it("completePrompt passes config overrides without tools when URL context and grounding disabled", async () => {
 		const options = {
 			apiProvider: "gemini",

src/api/providers/gemini.ts

@@ -140,7 +140,8 @@ export class GeminiHandler extends BaseProvider implements SingleCompletionHandl
 				tools.push({ urlContext: {} })
 			}
 
-			if (this.options.enableGrounding) {
+			// Only enable Google Search if the model supports grounding
+			if (this.options.enableGrounding && info.supportsGrounding) {
 				tools.push({ googleSearch: {} })
 			}
 		}
@@ -368,7 +369,8 @@ export class GeminiHandler extends BaseProvider implements SingleCompletionHandl
 			if (this.options.enableUrlContext) {
 				tools.push({ urlContext: {} })
 			}
-			if (this.options.enableGrounding) {
+			// Only enable Google Search if the model supports grounding
+			if (this.options.enableGrounding && info.supportsGrounding) {
 				tools.push({ googleSearch: {} })
 			}