fix: Adjust max tokens for Anthropic and improve Google tools handling

- Reduce default max tokens for Anthropic to 1/3 of model max
- Fix Google provider to properly handle empty tools array
- Ensure toolConfig is undefined when no tools are present

packages/ai/src/providers/anthropic.ts

@@ -261,7 +261,7 @@ function buildParams(
 	const params: MessageCreateParamsStreaming = {
 		model: model.id,
 		messages: convertMessages(context.messages, model),
-		max_tokens: options?.maxTokens || model.maxTokens,
+		max_tokens: options?.maxTokens || (model.maxTokens / 3) | 0,
 		stream: true,
 	};