This article examines Vercel AI SDK, a TypeScript library for building AI-powered user interfaces and applications and its integration with VoltAgent.

Updated: October 14, 2025 — This article reflects AI SDK 5.0, covering typed chat messages, agentic loop control, SSE-based streaming, dynamic tooling, speech APIs, and the global provider system.

A Quick Look at Vercel AI SDK​

Vercel AI SDK provides a unified toolkit for working with Large Language Models (LLMs) from multiple providers (OpenAI, Anthropic, Google Gemini, etc.) using a single API.

Instead of writing separate integrations for each model provider, you can use one consistent API.

For building autonomous AI agents that make decisions and interact with tools, frameworks like VoltAgent provide the necessary architecture. We'll examine this combination in detail.

Core Features (Updated for AI SDK 5)​

Vercel released AI SDK 5 on July 31, 2025, introducing major architectural changes and new capabilities.

Key Additions​

• Typed chat messages — UIMessage vs. ModelMessage. Convert UI messages to model messages before streaming for persistence and type safety.
• Agentic Loop Control — fine-tune or stop multi-step tool calls using stopWhen and prepareStep. Includes a lightweight Agent class that wraps generateText and streamText.
• SSE-based Streaming — Server-Sent Events replace WebSockets for stable real-time responses and partial data streaming.
• Dynamic Tooling — define tools dynamically with inputSchema and outputSchema instead of parameters and result. Runtime-defined tools and improved schema validation.
• Speech & Audio APIs — experimental text-to-speech and transcription support for OpenAI, ElevenLabs, Deepgram.
• Global Provider System — models can be referenced simply as "openai/gpt-4o"; provider setup is handled automatically.
• Zod 4 + MCP V2 Support — upgraded schema and protocol for reasoning, sources, and image generation.

Core SDK Functions​

Model Provider Support The SDK supports multiple model providers (OpenAI, Anthropic, Google Gemini, Hugging Face) through a single API. This eliminates provider-specific integration code for each model.

Streaming The SDK supports streaming responses for both text and structured data (JSON). For Next.js applications, React hooks like useChat and useCompletion handle common UI patterns.

Additional Components:

• generateText / streamText: Functions for text generation with streaming support.
• generateObject / streamObject: Generate structured data (JSON) with schema validation using Zod. Model output conforms to the defined schema structure. Model support for structured output varies by provider.
• Function Calling: Models can invoke predefined functions or tools. An agent can fetch data from an API or execute actions during conversation.
• Multi-modal Support: Process inputs beyond text, such as images. The SDK passes multi-modal messages to models that support this capability.
• Provider-Specific Options: Pass provider-specific parameters directly to underlying SDK functions through the provider object for model-specific features.

Example Code (AI SDK 5)​

import { generateText } from "ai";
import { openai } from "@ai-sdk/openai";

const result = await generateText({
  model: openai("gpt-4o"),
  prompt: "Explain what an agentic loop is in one sentence.",
});
console.log(result.text);

This structure now supports typed responses, streamed outputs, and custom data chunks.

VoltAgent: Building Autonomous AI Agents​

VoltAgent is a TypeScript framework for creating autonomous AI agents. While Vercel AI SDK focuses on model communication, VoltAgent provides the agent architecture tools, memory, reasoning, and coordination.

Refer to Vercel AI SDK docs on Voltagent.

Core VoltAgent Concepts​

• Instructions — define behavior and purpose
• Tools — external actions or APIs
• Memory — state and context
• Sub-agents — task delegation
• Providers — model connection layer

Integration with Vercel AI SDK​

VoltAgent integrates with AI SDK 5 through the @voltagent/vercel-ai provider. This allows agents to use Vercel's model APIs (generateText, streamText, generateObject) directly.

import { Agent } from "@voltagent/core";
import { openai } from "@ai-sdk/openai";

const agent = new Agent({
  name: "Vercel Powered Assistant",
  instructions: "Use OpenAI model via Vercel AI SDK.",
  model: openai("gpt-4o"),
});

async function run() {
  const res = await agent.generateText("Hello from VoltAgent!");
  console.log(res.text);
}

npm install @voltagent/core @ai-sdk/openai

This setup lets VoltAgent use AI SDK 5's advanced features (typed streaming, tool calls, agentic loops) while adding memory and observability via VoltOps.

Observability and VoltOps Integration​

VoltAgent integrates telemetry from VoltOps, enabling traceable AI calls:

import { withTelemetry } from "@voltagent/vercel-ai-exporter";
import { generateText } from "ai";

await withTelemetry({
  traceName: "order_agent",
  metadata: { agentId: "123", session: "abc" },
})(async () => {
  const result = await generateText({
    model: openai("gpt-4o"),
    prompt: "Hi!",
  });
});

VoltOps collects structured traces, tool call timing, and metadata for debugging and optimization.

Use Cases​

Streaming Chatbots For chatbots handling customer service or queries, streaming responses improves user experience. VoltAgent with VercelAIProvider uses the streamText function to stream responses as they generate.

Structured Data Extraction Extract specific information (keywords, technical specifications) from text into JSON format. VoltAgent uses Vercel AI SDK's generateObject with Zod schemas to enforce output structure.

Agentic Automation VoltAgent orchestrates multiple AI SDK tools dynamically for complex workflows. The Vercel AI Provider supports passing provider-specific configuration options through VoltAgent when needed.

Migration Notes​

If upgrading from AI SDK 4 → 5:

• Update packages to ai@5.0.0 and @ai-sdk/provider@2.0.0
• Replace deprecated parameters with inputSchema
• Update UI states (partial-call → input-streaming, result → output-available)
• Run Vercel's codemods for automatic refactoring

Summary​

• Vercel AI SDK 5 adds a new typed protocol, agentic loops, SSE streaming, speech APIs, dynamic tools, and global providers.
• VoltAgent builds on top, adding autonomous behavior, memory, and VoltOps observability.

Together, they form a complete ecosystem for modern AI agents — from LLM communication to full agent orchestration.

References​

• Vercel AI SDK 5 Blog
• AI SDK Migration Guide 5.0
• VoltAgent Docs