How to Give Every AI Agent Its Own Phone Number

The Identity Problem

When you run one AI agent, sharing your personal phone number works fine. When you run ten, it becomes messy. When you run a hundred, it's impossible. Every agent that interacts with the real world — signing up for services, receiving verification codes, making calls — needs its own phone number.

This is the agent identity problem. Without isolated phone numbers, incoming messages become ambiguous, OTP codes get misrouted, and your agents can't operate independently. The solution is simple: give every agent its own number.

Why Shared Numbers Break at Scale

Developers often start by routing all SMS through a single Twilio or Telnyx number. This works for demos but fails in production for three reasons:

• Message collision: When two agents trigger OTP verification at the same time, the incoming codes land in the same inbox. Which code belongs to which agent? You'd need a routing layer that parses sender IDs, timestamps, and message content — fragile and error-prone.
• Rate limits: Carriers and services throttle per-number. A single number receiving hundreds of SMS per hour gets flagged or blocked. Per-agent numbers distribute the load naturally.
• Audit trail: When something goes wrong, you need to know which agent did what. Shared numbers make forensics nearly impossible. Isolated numbers give you a clean audit trail per agent.

AgentCall's Per-Agent Model

AgentCall is built around a core abstraction: the agent. Every phone number, API key, webhook, and usage record is scoped to an agent. This isn't just organizational — it's how the system enforces isolation at every layer.

When you provision a number, it belongs to one agent. When an SMS arrives, it's routed to that agent's webhooks. When you check usage, you see per-agent breakdowns. This model maps directly to how autonomous software works: each agent is an independent unit with its own identity.

Step 1: Create an Agent

Each agent gets its own API key, usage quota, and webhook configuration. Think of it as a tenant in a multi-tenant system.

Step 2: Provision a Number

import AgentCall from 'agentcall';

const client = new AgentCall({ apiKey: 'ac_live_...' });

// Provision a real SIM number for this agent
const number = await client.numbers.provision({
  country: 'US',
  type: 'sim',
  label: 'support-agent-west-coast',
});

console.log(number.number); // +15551234567

The label field lets you tag numbers for easy identification in your dashboard and logs. Each provisioned number is automatically scoped to the agent whose API key you used.

Step 3: Set Up Webhooks

// Register a webhook to receive events for this agent
await client.webhooks.create({
  url: 'https://my-app.com/agent/west-coast/webhook',
  events: ['sms.received', 'sms.otp', 'call.completed'],
});

// Incoming events are automatically routed to this agent's webhook
// No shared inbox, no message collision

Webhooks are agent-scoped too. When an SMS arrives at this agent's number, the event is delivered only to this agent's webhook endpoint. Other agents never see it.

How This Compares to Twilio and Telnyx

Traditional CPaaS platforms like Twilio and Telnyx are powerful, but they're built for human developers building traditional apps — not for fleets of autonomous agents. Here's the difference:

• Twilio: Numbers belong to an account. You manage routing, isolation, and per-agent billing yourself. There's no native “agent” concept — you build it from scratch.
• Telnyx: Similar to Twilio. Great API, but agent-level isolation is your responsibility.
• AgentCall: Agents are first-class citizens. Numbers, webhooks, usage, and billing are scoped per-agent out of the box. No routing layer to build.

Real-World Patterns

Pattern 1: One Agent Per Customer

If you're building a customer support platform, each customer gets their own AI agent with a dedicated phone number. Customers call or text their agent directly. No IVR menus, no hold queues.

Pattern 2: One Agent Per Task

A research agent that signs up for services needs its own number for OTP verification. A sales agent that makes outbound calls needs a different number with a local area code. A monitoring agent that receives SMS alerts needs a third. Each task, each number.

Pattern 3: Dynamic Scaling

// Spin up agents dynamically based on demand
async function createAgentWithNumber(taskId: string) {
  const number = await client.numbers.provision({
    country: 'US',
    type: 'local',
    label: `task-${taskId}`,
  });

  await client.webhooks.create({
    url: `https://my-app.com/tasks/${taskId}/webhook`,
    events: ['sms.received', 'sms.otp'],
  });

  return number;
}

// Scale from 1 to 1,000 agents programmatically
const numbers = await Promise.all(
  taskIds.map(id => createAgentWithNumber(id))
);

Pricing

AgentCall's free tier includes 1 phone number, 50 SMS, and 10 voice minutes — enough to prototype and test. The Pro plan ($19.99/month) supports unlimited numbers at $2/month each for local numbers or $8/month for real SIM numbers. Usage is billed per-message ($0.015) and per-minute ($0.035).

FAQ

How many phone numbers can one agent have?

There's no limit on the Pro plan. You can provision as many numbers as your agent needs. Each number is independently managed and billed.

Can I transfer a number between agents?

Currently, numbers are bound to the agent that provisioned them. To move a number, you'd release it from one agent and re-provision on another. Number porting between agents is on the roadmap.

What's the difference between a local number and a SIM number?

Local numbers ($2/month) work for SMS and voice but may be flagged as VoIP by strict verification services. SIM numbers ($8/month) are issued by mobile carriers and pass verification on platforms like Stripe, WhatsApp, and banks that reject VoIP.