Facebook Messenger bot for customer service: windows, tags and handoff

A Messenger bot is a Meta app connected to one or more Facebook Pages. The app subscribes to each Page through the Page's subscribed_apps edge, which requires the pages_messaging and pages_manage_metadata permissions. Meta then sends events such as new messages and button taps to your webhook, and your bot replies through the Send API.

Meta also gives you fixed entry points. Tapping the Get Started button sends a postback, which is a good moment for a welcome message. A persistent menu, with up to 20 items, can include a "Talk to a person" option; it only appears once a Get Started button is set.

Messenger's standard messaging window gives you 24 hours to respond after a person messages your Page, and messages inside it may include promotional content. If you send a regular message after the window closes, the Send API returns error 1545041.

Meta limits HUMAN_AGENT to issues that can't be resolved within the standard window, such as a request that arrives while your business is closed for the weekend or a case that takes more than a day. Automated messages are a disallowed use of the tag, so the bot can't use it to send late follow-ups on its own.

Several apps can work on the same Page, for example your bot and a helpdesk. The handover protocol lets you pass a conversation from one app or inbox to another, and the messaging_handovers webhook reports when control is passed, taken or changed. Apps that don't control the thread receive standby events instead of regular message events.

Meta has been moving this toward Conversation Routing. A 2021 update removed the need to assign primary and secondary roles and added Exclusive and Idle modes. Routing rules can now be managed in your Page settings, and when Conversation Routing is enabled, the Conversations API returns an is_owner field so your app answers only threads it controls.

• Offer a clear way out: Meta's docs mention escalating via a fallback intent, a keyword or quick replies.
• Before passing control, post a short summary (topic, order number, what the bot already tried) where the agent will see it.
• Tell the customer what happens next, including your hours if nobody is online.
• When the agent is done, return control to the bot so the next question is answered automatically.

• Disclosure: when applicable law requires it, automated chat experiences must disclose that the person is talking to an automated service, for example at the start of a conversation or when a human hands back to automation. Meta suggests disclosing even where it isn't required and calls out California and Germany.
• Responsiveness: fully automated experiences must respond to all user input within 30 seconds. Hybrid setups that mix bots and people should update the response setting in Page Settings under Advanced Messaging.
• No promotion in tagged messages: message tags can't be used for advertising, marketing or solicitation.
• App approval: your app must be approved before it can use the HUMAN_AGENT tag.

Most helpdesks can receive Messenger conversations as tickets. In Zendesk, Messenger is a messaging channel in the Agent Workspace, and Zendesk documents a few practical limits:

• Agents have seven days to respond before the messaging window closes, after which the reply box is blocked.
• Replies an agent sends directly in Messenger don't sync back to Zendesk, so agents should answer from Zendesk.
• Messages longer than 2,000 characters are not delivered.

If your bot runs as a separate app, decide which app controls the thread by default and when control moves; otherwise the bot and the helpdesk may both answer the same customer.

TascaLab builds Messenger bots that work on top of Zendesk, Freshdesk, Jira, Slack or your internal tools, using APIs, webhooks, and Make or n8n. A Starter Chat Bot ($400) covers one or two channels; a Standard Chat Bot ($575) covers three to five channels, such as Messenger, Instagram and WhatsApp, with more complex conversations and smoother handoffs. Each project includes 30 days of post-launch support and basic documentation, and most setups take 1–3 weeks. Book a free 30-minute Health Check call to map your current Messenger flow.