Building Enterprise AI Agents with Next.js 15 & Vercel AI SDK

Autonomous AI agents capable of querying databases, executing API calls, and streaming structured responses are becoming standard in modern SaaS applications.

1. Core Agent Loop Architecture

An enterprise agent consists of:

1. Model Router: Dynamically routes between fast models (GPT-4o-mini) for classification and reasoning models (Claude 3.5 Sonnet) for execution.

2. Deterministic Tool Declarations: Type-safe tool definitions with Zod schemas.

3. Execution Sandbox: Secure Server Actions with rate limiting and database row-level security (RLS).

import { generateText, tool } from "ai";
import { openai } from "@ai-sdk/openai";
import { z } from "zod";

export async function runQueryAgent(prompt: string) {
  const result = await generateText({
    model: openai("gpt-4o"),
    prompt,
    tools: {
      fetchCustomerRecord: tool({
        description: "Retrieve customer CRM record by email",
        parameters: z.object({ email: z.string().email() }),
        execute: async ({ email }) => {
          return db.customer.findUnique({ where: { email } });
        },
      }),
    },
    maxSteps: 5,
  });

  return result.text;
}

2. Production Safety Guidelines