7. Serve an HTTP API

Support assistant tutorial This checkpoint uses matching @agentium/core@4.0.0 and @agentium/transport@4.0.0 packages. V4 requires an explicit local or authenticated security mode.

npm install express
npm install --save-dev @types/express

It serves a basic support Agent on loopback. Add the tools you have verified in earlier checkpoints to the support Agent as needed.

Complete checkpoint

support.ts

import express from "express";
import { Agent, openai } from "@agentium/core";
import { createAgentRouter } from "@agentium/transport";

const support = new Agent({
  name: "support",
  model: openai(process.env.OPENAI_MODEL ?? "gpt-6.1-sol"),
  instructions: "Help customers with orders. Ask for an order ID when it is missing.",
});
const app = express();
app.use(express.json({ limit: "1mb" }));
app.use("/api", createAgentRouter({
  registry: false,
  agents: { support },
  security: { mode: "local" },
}));
const server = app.listen(3000, "127.0.0.1", () => {
  console.log("Support API: http://127.0.0.1:3000/api/agents/support/run");
});

let closing = false;
function shutdown() {
  if (closing) return;
  closing = true;
  server.close((error) => {
    void support.close().catch(console.error);
    if (error) { console.error(error); process.exitCode = 1; }
  });
}
process.once("SIGINT", shutdown);
process.once("SIGTERM", shutdown);

Run it

npx tsx support.ts

Verify the result

In another terminal, make a request:

curl http://127.0.0.1:3000/api/agents/support/run \
  -H 'Content-Type: application/json' \
  -d '{"input":"Where is my order?"}'

The response should contain an agent answer asking for an order ID. registry: false exposes only the explicit support map. Stop the server with Ctrl+C. The shutdown handler stops new connections and closes the Agent after existing connections finish. A production host also needs bounded drain time, cancellation for active requests, and cleanup for separately owned resources. Local mode is for trusted local use. Before exposing this API, implement verified identity and resource ownership through authenticated hosting. Do not solve deployment by changing the bind address alone.

Prepare the application for deployment

Continue to the next chapter.

Start here

Build a support assistant

Setup and release

7. Serve an HTTP API

Complete checkpoint

Run it

Verify the result

Prepare the application for deployment

​Complete checkpoint

​Run it

​Verify the result

Prepare the application for deployment

Complete checkpoint

Run it

Verify the result