Your own agent

Your agent imports nothing from Vendo. The door speaks MCP over streamable HTTP, so the client SDK you already have reaches it. The only Vendo-shaped part is the bearer, and that is one method call.

Get the token

Ask your composition. Pass a request and it reads who is signed in from the session cookie; pass a user id and it acts as that person.

agent.ts

import { vendo } from "@/lib/vendo";

export async function runForRequest(request: Request) {
  const accessToken = await vendo.tokenFor(request);
  // …
}

jobs/nightly.ts

import { vendo } from "@/lib/vendo";

const accessToken = await vendo.tokenFor("user_1904");

The id is one of your user ids, spelled the way your product spells it — whatever your own principal() resolves for that person. Everything the agent does with the token is attributed to them. A subject that is not a real id — blank, null, undefined, or not a string at all — is refused here rather than minting a token that dies on the first tool call.

Connect

The client is the stock MCP SDK, which is your install, not Vendo’s:

npm install @modelcontextprotocol/sdk

pnpm add @modelcontextprotocol/sdk

One URL and one header.

agent.ts

import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StreamableHTTPClientTransport } from "@modelcontextprotocol/sdk/client/streamableHttp.js";

export async function connect(accessToken: string): Promise<Client> {
  const client = new Client({ name: "acme-agent", version: "1.0.0" });
  await client.connect(new StreamableHTTPClientTransport(
    new URL(`${process.env.VENDO_BASE_URL}/api/vendo/mcp`),
    { requestInit: { headers: { authorization: `Bearer ${accessToken}` } } },
  ));
  return client;
}

The path is fixed at /api/vendo/mcp under your own origin. It never points at a broker, so switching sign-in posture later invalidates nothing here.

One session per conversation

Connect once and keep the client for the whole conversation. The door pins each MCP session to the subject and client id that opened it, and answers 404 Session not found if either moves. This matters most for approvals. A parked call resumes only when the retry lands on the same session, so an agent that reconnects per call parks forever.

Read the result

The door never fails a tool call as a protocol error — a retry on a protocol error would re-execute a write that already happened. Everything arrives in-band.

const result = await client.callTool({ name: "host_setCardLimit", arguments: args });

if (result.isError) {
  // "This action needs approval. Approval apr_… is waiting in Maple's
  // Vendo approvals queue — resolve it there, then retry."
  return result.content[0].text;
}
return result.structuredContent;

Hand that text back to your model as the tool result. It already says what happened and what the next move is, which is enough for the model to retry or to tell the person. Successful calls carry the output twice: as text for the model, and as structuredContent for your own code.

Long calls need your opt-in

Your client abandons a tools/call after 60 seconds by default, and generating a screen with vendo_make routinely runs longer. The door beats notifications/progress every 15 seconds for any call that carries a progress token, but the SDK extends the deadline only when you asked it to — so a client that receives every frame still gives up at 60 seconds. Ask for both. onprogress is what puts the progress token on the request, and resetTimeoutOnProgress is what makes the frames count.

const result = await client.callTool(
  { name: "vendo_make", arguments: args },
  undefined,
  { onprogress: () => {}, resetTimeoutOnProgress: true },
);

When ten minutes runs out

A token lasts ten minutes and has no refresh path. An expired one answers 401 with a WWW-Authenticate challenge on the next request. Call tokenFor again and reconnect — for work that runs longer than one token, mint per unit of work rather than holding one open.

The whole loop

agent.ts

const accessToken = await vendo.tokenFor("user_1904");
const client = await connect(accessToken);

const { tools } = await client.listTools();
const step = await model.decide({ task, tools });

const result = await client.callTool({
  name: step.name,
  arguments: step.arguments,
});
task.push(result.isError ? result.content[0].text : result.structuredContent);

What the agent may call, and what happens to a call on the way to your API, is in How the door works.

Get started

In your backend

Install with your agent

Vendo's Full-Stack Agent

In your existing agent

From outside agents

Generated UI & apps

Make it yours

Capabilities

Production

Users & orgs

Your own agent

Get the token

Connect

One session per conversation

Read the result

Long calls need your opt-in

When ten minutes runs out

The whole loop

​Get the token

​Connect

​One session per conversation

​Read the result

​Long calls need your opt-in

​When ten minutes runs out

​The whole loop

Get the token

Connect

One session per conversation

Read the result

Long calls need your opt-in

When ten minutes runs out

The whole loop