Email for a Vercel AI SDK agent

Register

The response carries the address and an API key that is shown exactly once.

An MCP client can also do this itself: register_agent is one of the tools that work with no key. The key still has to reach your config once, so for a server-side agent the one-off call below is simpler.

# Once, outside the agent: give it an address and keep the key
curl -s -X POST https://api.mailgi.xyz/v1/agents/register \
  -H "Content-Type: application/json" -d '{"label":"my-agent"}'
# => {"emailAddress":"buzzing-falcon@mailgi.xyz","apiKey":"amb_..."}

export MAILGI_API_KEY=amb_...   # shown once: store it

The agent

The http transport is Streamable HTTP, which is what Mailgi serves. The key goes in as an ordinary header.

tools() returns all 67 tools: domains, keys, webhooks, billing. Destructuring the three mail tools keeps the model focused; add mail_move or mail_delete if it should file or clean up.

Close the client when the request is done. In a route handler, close it in onFinish when you use streamText.

The client and tool calls were run against the live API with ai 7.0 and @ai-sdk/mcp 2.0, and the example type-checks. Swap the model line for any provider.

// npm install ai @ai-sdk/mcp @ai-sdk/anthropic
import { generateText, stepCountIs } from 'ai';
import { createMCPClient } from '@ai-sdk/mcp';
import { anthropic } from '@ai-sdk/anthropic';

const mailgi = await createMCPClient({
  transport: {
    type: 'http',
    url: 'https://api.mailgi.xyz/mcp',
    headers: { Authorization: `Bearer ${process.env.MAILGI_API_KEY}` },
  },
});

try {
  const { mail_send, mail_list, mail_get } = await mailgi.tools();
  const { text } = await generateText({
    model: anthropic('claude-sonnet-5-5'),
    tools: { mail_send, mail_list, mail_get },
    stopWhen: stepCountIs(5),
    prompt: 'Check my inbox and summarise anything new.',
  });
  console.log(text);
} finally {
  await mailgi.close();
}