AI email support agent

Your AI email support agent answers mail sent to its generated address, mail forwarded from your company addresses, or mail in a connected Google or Microsoft inbox. Replies stay in the customer’s email thread, and your team can step in at any point.

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What it does

• Receives email in one of three ways: a generated agent address, a company address that forwards to it, or a connected Gmail or Outlook inbox.
• Replies in the same thread, keeping the subject and threading headers, from the address the customer wrote to when it is one you selected.
• Reads attached images and the text of PDF, DOCX, plain text, Markdown and CSV files, up to five files of 5 MB each for an automatic reply.
• Holds suspected spam, skips mailing lists and automatic mail, and never answers blocked senders.
• Waits up to one hour before sending, if you set a reply delay, and pauses when a person takes over from the helpdesk inbox.

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What you need

• The Owner or Member role. Viewers can inspect the settings and preview email formatting without saving. See workspace roles.
• A plan with automatic email replies: Hobby and up. The Helpdesk inbox your team works from comes with Standard and up.
• For the generated agent address: an enabled Helpdesk and an available email service.
• For a company address with forwarding: access to the mailbox or its mail routing settings, plus the domain’s DNS.
• For a connected inbox: permission to authorise read and send access to a Google or Microsoft mailbox. Choose a dedicated support inbox.

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Set it up

Pick the setup that matches where your support mail lives. Each ends with the same test: a message from an outside mailbox that appears under Conversations and gets a reply.

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The generated agent address

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A company address with forwarding

If mail never reaches Centillion, read the forwarding guide. If the custom sender is not ready, read the DNS guide.

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A connected Gmail or Outlook inbox

Only messages in the inbox folder are answered. Mail your provider or rules move elsewhere is left alone, and mail that arrived before you enabled automatic replies is not answered. Shared Microsoft mailboxes and sending aliases are not separate account choices. If the connection shows Needs attention, read the error and reconnect: an administrator can revoke access even when the inbox worked before.

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Use it every day

Open Channels, Email, Manage, or the Playground with Email selected. Both edit the same configuration, so saving in the Playground changes the live channel; use a test agent to try settings safely.

• Reply addresses. When a customer writes to a selected address, the reply comes from that address. Otherwise it comes from the first selected address, or from the generated address when none is selected. A connected inbox sends through the mailbox you authorised.
• Email display name. The sender name beside the address, such as Acme Support. It changes the name, not the authenticated address. For teammate replies, Helpdesk email settings can use the responder’s name or a fixed team name.
• Deliverability alert contact. An active team member who gets alerts about recipient-server delays, bounces, spam complaints or failed delivery. None turns them off. Saving the contact sends no test alert. Alerts work for a connected inbox even with Helpdesk off; pick a member with an email address who can investigate.
• Blocked senders. Complete addresses that never get an automatic reply. Their messages stay in conversations, and changes apply to future mail. Type an address and press Enter, comma or semicolon, or paste several at once. Each becomes a chip you remove with ×; duplicates appear once.
• Spam detection. Holds suspected spam without replying. Your team can reply by hand or choose Reply anyway. Whitelisted senders skip the spam check, but not the block list or the reply-loop checks. Turning detection off keeps the whitelist.
• Reply delay. Seconds or minutes, up to one hour. Zero or empty sends at once. The agent prepares the answer on arrival and holds delivery; a pending reply shows its remaining wait. Taking over cancels waiting replies, and the customer never sees them. Team replies and Reply anyway send at once.
• AI composition disclaimer. Marks automatic replies, by default with This message is composed by AI. You can change the wording. Teammate replies never carry it.
• Signature. A formatted signature with links, lists, text styles and contact details. A saved Helpdesk signature takes precedence for AI replies; when it is empty, AI replies use this one while its switch is on. Teammate replies use the Helpdesk signature. Switching it off keeps the draft; clearing the editor and saving deletes it. To remove signatures from both kinds of reply, clear the Helpdesk signature and turn off or clear this one. Keep it short enough to read on a phone.

The Playground’s Email preview is a static sample of an outgoing email: From name, address, signature, disclaimer and footer. It has no composer, does not generate an answer or send email, and does not check forwarding or DNS. Use Chat bubble to try answers (the Preview and Install buttons appear only there), then send a real test email. Actions that send messages or create tickets need a real channel test too; see Troubleshooting. When your team takes over a conversation, replies pause. Choose Allow AI replies in the ticket when the agent should answer again.

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Hand email conversations to Zendesk

A Create ticket action with Zendesk as its Helpdesk destination creates a Zendesk ticket and pauses automatic replies on that email thread. Your team answers in Zendesk. A Solved or Closed ticket resumes the original conversation unless a newer manual takeover is active. See Zendesk email handoff to connect the account, configure the action, and test ticket creation, customer follow-ups, and resumption. The Email Playground does not run a handoff.

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Limits and good to know

• Addresses and domains. Up to 3 custom email domains per workspace and 20 addresses per domain, counting all of the workspace’s agents.
• Incoming files. Helpdesk keeps up to 5 attachments per email, 25 MB per file and 125 MB combined. Automatic AI replies support up to 5 files of 5 MB each. PDFs are limited to 5 pages and 2,000 tokens per page, and document text to 30,000 characters per email. Unsupported or omitted files, scanned or unreadable PDFs, and documents over the limit pause the AI reply for your team. Use a model that accepts images if customers send pictures. An email can carry an attachment with no body. Test the file types your customers use through the real configured address; your team can attach files to replies from Helpdesk too.
• Mail the agent skips. Mailing lists, bulk mail, automatic replies, out-of-office messages, common no-reply addresses such as mailer-daemon@ and postmaster@, blocked senders, mail you sent yourself, and mail from another generated Centillion Helpdesk address.
• Delivery failures. Centillion retries a failed send. A reply that still cannot be sent stops retrying, and the alert contact is told.
• Formatting. Replies keep their Markdown formatting in the HTML email, including text inserted from Helpdesk macros. Plain-text readers get the same content without formatting.
• Branding. The Powered by Centillion footer is hidden on automatic replies, teammate replies, new Helpdesk emails and previews once the white-label add-on is active; the signature and disclaimer keep their own settings. Owners buy and manage it in Workspace settings, Billing; see Plans and billing.
• Campaign links. Email replies keep their original link destinations. Visitors who reach your site from an email campaign keep their UTM parameters on agent links through the script embed.

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Questions

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Which of the three setups should I choose?

Use a connected inbox if your support mail already lives in Gmail or Outlook: it needs no forwarding or DNS. Use a company address with forwarding if customers already write to an address on your domain and should get replies from it. The generated address alone is the quickest way to test.

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Why did a test email get no reply?

Check that Automatic replies is on, that the sender is not blocked, and that the message was not held as spam. A connected inbox answers only mail in the inbox folder that arrived after you enabled replies.

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Can customers see that a reply was written by AI?

Only if you enable the AI composition disclaimer. It is added to automatic replies and never to replies your team writes.

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What happens when my team takes over?

Waiting automatic replies are cancelled and the conversation pauses. Your team replies from the ticket, and Allow AI replies hands it back to the agent.

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Before I use a company address with customers, what should I test?

Send a new email, check the AI reply, send a follow-up in the same thread and take over as a teammate. Check the From name, address, signature and disclaimer in the received mail, and try blocked senders, spam and the reply delay with accounts you control.

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Can the same agent answer chat and phone too?

Yes. One agent answers on every channel you connect; see What Centillion is.

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Try it

Write to your agent’s generated address from your own mailbox. The reply lands in the same thread, and the conversation shows up in the dashboard. Or ask the assistant on this page.

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