vercelAIToolChoiceSchema: ZodUnion<
    [
        ZodLiteral<"auto">,
        ZodLiteral<"none">,
        ZodLiteral<"required">,
        ZodObject<
            { toolName: ZodString; type: ZodLiteral<"tool"> },
            "strip",
            ZodTypeAny,
            { toolName: string; type: "tool" },
            { toolName: string; type: "tool" },
        >,
    ],
> = ...

Vercel AI SDK Tool Choice Schema