Model Context Protocol (MCP)

The AI SDK supports connecting to Model Context Protocol (MCP) servers to access their tools, resources, and prompts. This enables your AI applications to discover and use capabilities across various services through a standardized interface.

Initializing an MCP Client

We recommend using HTTP transport (like StreamableHTTPClientTransport) for production deployments. The stdio transport should only be used for connecting to local servers as it cannot be deployed to production environments.

Create an MCP client using one of the following transport options:

• HTTP transport (Recommended): Either configure HTTP directly via the client using transport: { type: 'http', ... }, or use MCP's official TypeScript SDK StreamableHTTPClientTransport
• SSE (Server-Sent Events): An alternative HTTP-based transport
• stdio: For local development only. Uses standard input/output streams for local MCP servers

HTTP Transport (Recommended)

For production deployments, we recommend using the HTTP transport. You can configure it directly on the client:

import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp';

const mcpClient = await createMCPClient({
  transport: {
    type: 'http',
    url: 'https://your-server.com/mcp',

    // optional: configure HTTP headers
    headers: { Authorization: 'Bearer my-api-key' },

    // optional: provide an OAuth client provider for automatic authorization
    authProvider: myOAuthClientProvider,
  },
});

Alternatively, you can use StreamableHTTPClientTransport from MCP's official TypeScript SDK:

import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp';
import { StreamableHTTPClientTransport } from '@modelcontextprotocol/sdk/client/streamableHttp.js';

const url = new URL('https://your-server.com/mcp');
const mcpClient = await createMCPClient({
  transport: new StreamableHTTPClientTransport(url, {
    sessionId: 'session_123',
  }),
});

SSE Transport

SSE provides an alternative HTTP-based transport option. Configure it with a type and url property. You can also provide an authProvider for OAuth:

import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp';

const mcpClient = await createMCPClient({
  transport: {
    type: 'sse',
    url: 'https://my-server.com/sse',

    // optional: configure HTTP headers
    headers: { Authorization: 'Bearer my-api-key' },

    // optional: provide an OAuth client provider for automatic authorization
    authProvider: myOAuthClientProvider,
  },
});

Stdio Transport (Local Servers)

The Stdio transport can be imported from either the MCP SDK or the AI SDK:

import { experimental_createMCPClient as createMCPClient } from '@ai-sdk/mcp';
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
// Or use the AI SDK's stdio transport:
// import { Experimental_StdioMCPTransport as StdioClientTransport } from '@ai-sdk/mcp/mcp-stdio';

const mcpClient = await createMCPClient({
  transport: new StdioClientTransport({
    command: 'node',
    args: ['src/stdio/dist/server.js'],
  }),
});

Custom Transport

You can also bring your own transport by implementing the MCPTransport interface for specific requirements not covered by the standard transports.

Closing the MCP Client

After initialization, you should close the MCP client based on your usage pattern:

• For short-lived usage (e.g., single requests), close the client when the response is finished
• For long-running clients (e.g., command line apps), keep the client open but ensure it's closed when the application terminates

When streaming responses, you can close the client when the LLM response has finished. For example, when using streamText, you should use the onFinish callback:

const mcpClient = await experimental_createMCPClient({
  // ...
});

const tools = await mcpClient.tools();

const result = await streamText({
  model: 'anthropic/claude-sonnet-4.5',
  tools,
  prompt: 'What is the weather in Brooklyn, New York?',
  onFinish: async () => {
    await mcpClient.close();
  },
});

When generating responses without streaming, you can use try/finally or cleanup functions in your framework:

let mcpClient: MCPClient | undefined;

try {
  mcpClient = await experimental_createMCPClient({
    // ...
  });
} finally {
  await mcpClient?.close();
}

Using MCP Tools

The client's tools method acts as an adapter between MCP tools and AI SDK tools. It supports two approaches for working with tool schemas:

Schema Discovery

With schema discovery, all tools offered by the server are automatically listed, and input parameter types are inferred based on the schemas provided by the server:

const tools = await mcpClient.tools();

This approach is simpler to implement and automatically stays in sync with server changes. However, you won't have TypeScript type safety during development, and all tools from the server will be loaded

Schema Definition

For better type safety and control, you can define the tools and their input schemas explicitly in your client code:

import { z } from 'zod';

const tools = await mcpClient.tools({
  schemas: {
    'get-data': {
      inputSchema: z.object({
        query: z.string().describe('The data query'),
        format: z.enum(['json', 'text']).optional(),
      }),
    },
    // For tools with zero inputs, you should use an empty object:
    'tool-with-no-args': {
      inputSchema: z.object({}),
    },
  },
});

This approach provides full TypeScript type safety and IDE autocompletion, letting you catch parameter mismatches during development. When you define schemas, the client only pulls the explicitly defined tools, keeping your application focused on the tools it needs

Using MCP Resources

According to the MCP specification, resources are application-driven data sources that provide context to the model. Unlike tools (which are model-controlled), your application decides when to fetch and pass resources as context.

The MCP client provides three methods for working with resources:

Listing Resources

List all available resources from the MCP server:

const resources = await mcpClient.listResources();

Reading Resource Contents

Read the contents of a specific resource by its URI:

const resourceData = await mcpClient.readResource({
  uri: 'file:///example/document.txt',
});

Listing Resource Templates

Resource templates are dynamic URI patterns that allow flexible queries. List all available templates:

const templates = await mcpClient.listResourceTemplates();

Using MCP Prompts

According to the MCP specification, prompts are user-controlled templates that servers expose for clients to list and retrieve with optional arguments.

Listing Prompts

const prompts = await mcpClient.listPrompts();

Getting a Prompt

Retrieve prompt messages, optionally passing arguments defined by the server:

const prompt = await mcpClient.getPrompt({
  name: 'code_review',
  arguments: { code: 'function add(a, b) { return a + b; }' },
});

Handling Elicitation Requests

Elicitation is a mechanism where MCP servers can request additional information from the client during tool execution. For example, a server might need user input to complete a registration form or confirmation for a sensitive operation.

Enabling Elicitation Support

To enable elicitation, you need to advertise the capability when creating the MCP client:

const mcpClient = await experimental_createMCPClient({
  transport: {
    type: 'sse',
    url: 'https://your-server.com/sse',
  },
  capabilities: {
    elicitation: {},
  },
});

Registering an Elicitation Handler

Use the onElicitationRequest method to register a handler that will be called when the server requests input:

import { ElicitationRequestSchema } from '@ai-sdk/mcp';

mcpClient.onElicitationRequest(ElicitationRequestSchema, async request => {
  // request.params.message: A message describing what input is needed
  // request.params.requestedSchema: JSON schema defining the expected input structure

  // Get input from the user (implement according to your application's needs)
  const userInput = await getInputFromUser(
    request.params.message,
    request.params.requestedSchema,
  );

  // Return the result with one of three actions:
  return {
    action: 'accept', // or 'decline' or 'cancel'
    content: userInput, // only required when action is 'accept'
  };
});

Elicitation Response Actions

Your handler must return an object with an action field that can be one of:

• 'accept': User provided the requested information. Must include content with the data.
• 'decline': User chose not to provide the information.
• 'cancel': User cancelled the operation entirely.

Examples

You can see MCP in action in the following examples: