Hello world: managed agent

With a managed agent, Wassist runs the whole loop for you: it receives the WhatsApp message, runs your agent, and sends the reply. You write a prompt. By the end of this page you’ll send “hi” to the sandbox number and get “Hello, world! 👋” back from your own agent.

Use your personal organization while testing on the sandbox (switch in Settings → Organization). Sandbox chats are filed under your personal organization, so an agent connected while a team organization is active won’t receive your messages.

1. Create the agent

Dashboard
SDK
cURL

Create a new agent

Give it a hello world prompt

Rename it to Hello World, then paste this into the Instructions box:

You are Hello World, a demo agent.
Whatever the user sends, reply with "Hello, world! 👋" on the first line,
then answer their message in one short sentence.

Save

Click Save in the bar at the bottom of the page.

Create an API key under Settings → Developers → API keys, then:

npm install @wassist/sdk

hello-agent.mjs

import { Wassist } from "@wassist/sdk";

const wassist = new Wassist({ apiKey: process.env.WASSIST_API_KEY });

const agent = await wassist.agents.create({ name: "Hello World" });

await wassist.agents.update(agent.id, {
  systemPrompt: [
    "You are Hello World, a demo agent.",
    'Whatever the user sends, reply with "Hello, world! 👋" on the first line,',
    "then answer their message in one short sentence.",
  ].join("\n"),
});

console.log(`Created ${agent.name}: https://wassist.app/agents/${agent.id}`);

WASSIST_API_KEY=your-api-key node hello-agent.mjs

Create an API key under Settings → Developers → API keys, then:

AGENT_ID=$(curl -s https://backend.wassist.app/api/v1/agents/ \
  -H "X-API-Key: $WASSIST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name": "Hello World"}' | jq -r .id)

curl -X PATCH https://backend.wassist.app/api/v1/agents/$AGENT_ID/ \
  -H "X-API-Key: $WASSIST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"systemPrompt": "You are Hello World, a demo agent. Whatever the user sends, reply with \"Hello, world! 👋\" on the first line, then answer their message in one short sentence."}'

2. Connect it to the sandbox

Open the sandbox number

Go to Numbers in the dashboard and click the number under Sandbox numbers.

Route your chat to the agent

In the Routing section, set Mode to Agent: let the connected agent reply, click Connect agent, choose Hello World, type its name to confirm, and click Connect agent.

This only changes your own chat with the sandbox number. Connecting an agent to the sandbox has to be done while signed in to the dashboard. API keys belong to the organization rather than a person, so they have no WhatsApp chat to route.

3. Say hi

From the phone you signed in with, open WhatsApp and send hi to the sandbox number:

You:         hi
Hello World: Hello, world! 👋
             Hi there, what can I help you with today?

That’s a working WhatsApp agent. Every conversation shows up under Conversations in the dashboard, along with the tools the agent called.

Send /reset in the chat at any time to start a fresh session with the agent.

Make it yours

Pick a model and thinking effort

On the agent’s page, choose the model and how much thinking effort it uses. More effort gives more considered answers but slower replies. Changing either requires a paid plan.From the API, set llmModel and reasoningEffort (none, low, medium, high or xhigh). Send null to go back to the model’s default. Not every model supports every level, and unsupported values return 400.

await wassist.agents.update(agent.id, { reasoningEffort: "low" });

Give it tools and knowledge

Under Capabilities you can add API tools, website lookups, MCP connectors, Shopify stores and installed Apps. See Configure tools.

Start from your website or Shopify store

Instead of starting blank, generate an agent from your files, your website or an idea. Selling on Shopify? Install the Shopify app and it builds a sales agent from your store.

Go live on your own number

Connect a WhatsApp Business number, then connect the agent to it the same way: Numbers → your number → Routing → Agent. From code:

await wassist.phoneNumbers.connectAgent("447700900100", {
  agentId: agent.id,
  applyToExisting: true,
});

See Deploy your agent.

Next steps

Webhook routing

Handle messages in your own code instead.

Core concepts

Agents, tools, conversations and memory.

Introduction

Get Started

Advanced

Hello world: managed agent

1. Create the agent

2. Connect it to the sandbox

3. Say hi

Make it yours

Next steps

Webhook routing

Core concepts

​1. Create the agent

​2. Connect it to the sandbox

​3. Say hi

​Make it yours

​Next steps

Webhook routing

Core concepts

1. Create the agent

2. Connect it to the sandbox

3. Say hi

Make it yours

Next steps