Guide · AI agents · For the owner whose customers ask about their own account

How Meta's AI agent checks it is talking to the account holder on WhatsApp: one-time codes, sign-in and signing out

Some answers cannot go to whoever happens to be holding the phone: a balance, a lease, a booking in someone's name. Meta has published two guides on how its AI agent for business confirms it is talking to the account holder, and on how long that confirmation should last. Both start from the same warning.

Published 6 October 2026

A phone number is not a person

Meta is plain about it. WhatsApp tells the business which number a message came from. It does not tell the business that the person holding that phone is the account holder. Meta treats the number as a strong hint that saves asking for an account number, never as proof. A returning customer recognised by their number can be greeted by first name, and nothing more, until they have proved who they are.

Meta also says that if a business's conversations never touch a particular person's account, it does not need any of this, and adding it will only lose conversations. Where it is needed, Meta suggests writing down which questions need which level, rather than one switch for everything:

Anyone: Opening hours, prices, timetables, policies. No sign-in, and the agent should not ask for one.
Recognised: The number matches a customer. It shortens signing in; it never replaces it.
Signed in: The customer has proved who they are in this conversation. Their own bookings, balance or contract can be discussed.
Proved again: For changes that are hard to undo, such as payment details, address or contact details. A sign-in twenty minutes ago says nothing about who is holding the phone now.

How the one-time code works

The code comes from the business's own system. The agent asks that system to send it, the customer types it back, and the business's system swaps it for a temporary pass. Meta holds the pass and attaches it to every later account question, without the agent ever seeing it. Meta's rules for the code itself:

Send it somewhere other than the chat: A code sent into the same WhatsApp conversation only proves someone controls that conversation, which was never in doubt. Meta calls a different channel the stronger design.
The chat is a permanent record: Whatever the customer types stays in their chat history, on every device where that account is open. So the code is the only secret that ever enters the chat, and it works once, briefly.
The agent never repeats the code: Meta says to forbid it from stating, confirming or spelling the code out. Asked directly, an agent without that rule will helpfully read it back.
No substitutes: Date of birth, part of an address, a recent order number: Meta says to name these as unacceptable, because otherwise the agent will accept them as reasonable.
The same answer for accounts that do not exist: Any difference in reply between a real account and an invented one tells a stranger which accounts exist, and the agent will pass that difference on.
A limit, then a person: Meta's example: three attempts and one resend, then a person. A handover is a better outcome than a loop.

Staying signed in, and signing out

Do not ask up front: Most conversations never need sign-in. Meta says asking first loses the ones that would have gone somewhere.
It lasts for one conversation: A sign-in belongs to the conversation, not the phone number, and does not carry into a new conversation.
Renewing is not proving again: A sign-in can be renewed quietly during a long conversation, but a renewed sign-in is as old as the original proof.
End it when the job is done: On completion, when the customer asks, after inactivity, and before handing over to a person. Meta notes most customers never ask to sign out, and a sign-in left open on a shared phone shows the next person the first person's details.
One account per sign-in: Switching to a different account inside the same sign-in is refused. End it and start again.

When a person takes over

Meta warns of a quiet gap: if the colleague taking over is not told whether the customer has been verified, the agent enforces the check and the colleague bypasses it. The handover should say so, with the reason for the handover but no account number. How a conversation passes to a person is in the conversation routing guide, and how much an order lookup should reveal on a number alone is in the order and basket guide.

Test what goes wrong. Wrong codes, expired codes, resends, a customer offering a date of birth instead, a customer asking the agent to repeat the code, and an account that does not exist.
Watch the ratio. Meta suggests alerting on how many codes are requested against how many are verified.

Questions

Isn't the WhatsApp number enough to know who we are talking to?

No. Meta says the number shows which phone the message came from, not that the person holding it is the account holder. It can save asking for an account number, but it is never the proof.

Where should the code be sent?

Meta calls sending it over a different channel from the WhatsApp chat the stronger design, offering only channels the customer has registered with the business.

What happens if the customer cannot verify?

After a set limit, Meta's example being three attempts and one resend, the conversation goes to a person, who is told the customer is not verified.

Does every business need this?

No. Meta says it is for conversations that reach a particular person's account. If yours never do, adding it only loses conversations.

How long does a sign-in last?

For that conversation only. Meta says to end it when the task is done, when the customer asks, after inactivity, and before handing over to a person.

Sources

Meta's developer documentation: Meta Business Agent, Customer OTP authentication, read 6 October 2026.
Meta's developer documentation: Meta Business Agent, User login, read 6 October 2026.

More plain-language notes like this one are on the guides page.

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