Microsoft Outlook in Agent Builder

The Outlook step lets an agent send, read and file mail in a Microsoft 365 mailbox as part of a run. It can email a customer when a job is finished, list what arrived overnight, reply in the same conversation, save a draft, download attachments, move a message into a folder or stamp a category on it. Each step does one thing, picked from 10 actions, and hands what Outlook sends back to the next step. The same mailbox also drives the Email received trigger, which starts an agent when a new message lands in a folder you choose.

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Job completed email

1,240 / 10,000 creditsValidateResetRunsSettingsUpdate & Publish

Job finished

Job status changed

Fetch the job

Get job

Write the note

GPT-5.6 Terra

Email the customer

1 action enabled

2

AI builderMap

1. 1Outlook in the Integration group of the Nodes panel.
2. 2The step on the canvas. Its summary reads 1 action enabled once you have chosen Send email.
3. 3Connection: the Outlook mailbox this agent uses. With more than one mailbox, Account picks which one this step uses.
4. 4Actions: the one action this step performs. Send email is selected.
5. 5To: who the message goes to. Here it is the customer's address at Northgate Housing.

Centrus works alongside Outlook. The mailbox stays in Microsoft 365, and the agent sends and reads from the account you sign in. The step does not manage the calendar. To ask about mail in a conversation rather than in an agent, see Microsoft Outlook in chat. How connections differ across chat, Agent Builder and Train is in Integrations overview.

Open the agent in Agent Builder and find Outlook at the top of the Integration group in the Nodes panel. Drag it onto the canvas and connect the step before it to its left-hand side. Until you choose an action, its summary on the canvas reads No actions selected.

Job finished

Job status changed

Outlook

No actions selected

2

1. 1Outlook in the Integration group. Drag it onto the canvas.
2. 2The new step. It reads No actions selected until you choose an action in its Details panel.

On a phone, Agent Builder shows the canvas only. The Nodes panel is hidden on screens narrower than 768 pixels and the Details panel on screens narrower than 1,024 pixels, so you can follow an agent's steps on a phone but need a tablet or computer to add an Outlook step or change its settings.

09:41

Centrus

Agents

Build modular AI workflows with reusable nodes

Chase overdue invoices

Save and Publish

Job finished

Job status changed

Fetch the job

Get job

Write the note

GPT-5.6 Terra

Email the customer

1 action enabled

The Outlook connection belongs to this agent alone. It is separate from the Microsoft Outlook card on the Integrations page, so connecting chat does not connect the agent, and connecting the agent does not connect chat. One connection covers every Outlook step on the agent and its Email received trigger, so you only sign in once per agent. An agent can hold more than one mailbox. Each Outlook step then picks which one to use.

You sign in with Microsoft. There is no customer ID or secret to copy. The person who signs in needs a mailbox the agent should send from, such as accounts@meridianfm.co.uk. Centrus asks Microsoft for permission to send mail, to read and write mail, to read and write calendars, and to read the signed-in profile. The calendar permission is requested even though this step has no calendar actions.

1. 1Save the agent with Save draft. Until it has been saved once, the Connection section reads Save this workflow as a draft first, then connect the account. and Connect is greyed out.
2. 2Select the Outlook step. In the Details panel, open Connection and click Connect.
3. 3Centrus leaves Agent Builder and opens Microsoft's account page. Choose the mailbox, then accept the permissions.
4. 4You return to the agent. Connection now reads Connected, followed by that mailbox's address.

Centrus does not store a password. Microsoft accepts or refuses the sign-in. If you close Microsoft's page before you finish, nothing is saved and Connection stays Not connected. If Centrus cannot open Microsoft at all, you see Failed to start Outlook connection. Try Connect again, and if it persists ask whoever looks after your Microsoft 365 sign-in.

Several mailboxes. After the first mailbox is connected, open Settings in the toolbar. Under Integrations, Add another account starts a second Microsoft sign-in and leaves the first mailbox in place. Each row can be renamed, made primary, or disconnected on its own. On the step, Account appears once the agent has two or more mailboxes, or if the step still points at a mailbox that has been disconnected. Primary account (default) follows whichever row is marked primary in Settings. A named row, such as john.martin@meridianfm.co.uk, locks this step to that mailbox. The list on the step shows the primary row with (primary) after the address.

Whose mailbox a run uses. Integration mode, in Settings, is shown to the agent's owner and to an organisation administrator. Agent-level is the default: every Outlook step uses the mailbox connected on the agent, whoever starts the run. Per-user is only offered when the agent starts from chat. The control is greyed out for a schedule or for Email received, and the note reads: Only available for workflows triggered from chat or manually: a scheduled run has no triggering user. In Per-user, Send email and Create draft use the Outlook account of the person who started the run, connected on their own Integrations page, not the agent's mailbox. The step's Connection section changes: it says Uses the credentials of whoever runs this workflow, and offers Check my own connection. The Account list is hidden, because a person's chat connection is a single mailbox.

Only those two actions work in Per-user. Reply to email, Read email, Get message, Get conversation, Find emails, Download attachments, Move email to folder and Set categories fail the run. The message says the action is not supported in that mode and that only sending and creating drafts are. Gmail is wider: its read actions work in Per-user as well. A BigChange step, or any other system, fails too. Keep an agent that reads or files Outlook mail, or that uses another system, on Agent-level. For how sharing and this switch fit together, see Share an agent.

Sharing and copying the agent. When you share an agent, its Outlook connection stays on the agent. People you share it with cannot see or copy the sign-in. On Agent-level, their runs send from the agent's mailbox. On Per-user, a Send email or Create draft step sends from their own Outlook, if they have connected it in chat. When you duplicate an agent, the steps are copied and the connection is not. The copy says to connect again. There is no Copy from existing agent for Outlook, because that list is only for connections that use a key rather than Microsoft sign-in. Sign in again on the copy, or add the mailboxes under Settings.

Disconnecting. Disconnect on the step removes Outlook from this agent. The confirmation reads Outlook disconnected from this agent. Every Outlook step and the Email received trigger stop until someone signs in again. Other agents keep their own mailboxes, and the Microsoft Outlook card in chat is left as it is. To drop one mailbox and keep another, disconnect that row under Settings, then Integrations, rather than using Disconnect on the step.

Select the step and open Actions in the Details panel. The line under the title reads What this step does with the connected Outlook account. On a step in the agent's main flow the list is a set of radio buttons, one action only, in this order: Send email, Reply to email, Read email, Get message, Get conversation, Find emails, Create draft, Download attachments, Move email to folder, Set categories. There is no search box. The canvas summary becomes 1 action enabled. It does not show the action's name.

Send email then shows Recipients and Fixed message. To, CC and BCC take one or more addresses, separated by commas. The mail is sent from the mailbox on this step. Subject and Body are the message. You can also attach a workbook by its ID, and, under Attachments (optional), tick Attach files from incoming item binaries to attach files an earlier step downloaded, such as a PDF. Left blank, that option attaches up to 20 files and 20,971,520 bytes in total. You can raise those boxes, up to 50 files and 26,214,400 bytes.

The help under Recipients says you can leave To blank so that an AI chooses the recipients at run time, and Fixed message says you can leave the subject and body blank for an AI to write the email. That is true when an Intelligence step calls Send email as a tool. On the main path, a blank To or Subject is sent through empty, and the send does not complete. Fill them in, or paste a reference from an earlier step.

To use a value from an earlier step, open Step data references at the top of the Details panel and click a field to copy its reference, then paste it into To, Subject or Body. In the job agent, Body holds the note written by Write the note. Message IDs are text, so the same paste works in Message ID on Reply to email, Get message and Move email to folder.

Reply to email opens Reply in thread. Reply body is required: the help says an empty body will not send. Message ID can stay empty, and the step replies to the incoming message. Reply all is off unless you tick it, in which case Microsoft is called with reply-all rather than reply. There is no To or CC. Do not use Send email when you want the answer to stay in the same conversation: that starts a new message.

Read email lists recent messages in a folder, by default the inbox, up to 10, and at most 50. Each row has the subject, sender, preview and id. Get message fetches one message in full, including the body and the list of attachments, and it marks that message as read. Get conversation loads the whole conversation onto the same item, under the conversation's messages. It does not make one item per message, and it does not mark anything as read. It defaults to 50 messages and stops at 100. Find emails is the one to use when the next step should handle each match on its own: it passes on one item per message, with the subject, sender, attachment list and body text. The filters are Subject contains, Body contains, From contains, an optional list of exact sender addresses, Within the last (hours), Folder and Max results. Only emails with attachments can be ticked. The default folder is the inbox, the default maximum is 25, and the cap is 100. A folder path such as Inbox/Invoices is resolved to that folder. Child folders of it are not searched.

Create draft saves a message in Drafts and does not send it. The panel does not show Recipients or Fixed message for it, so on the main path there is nowhere to type To or Subject. Use it as a tool on an Intelligence step, where the AI supplies those, or use Send email when you want to set them yourself. Create draft also cannot attach files. Download attachments saves each file from the incoming messages and passes on one item per file, ready for a later step to read or attach. Inline images are skipped, and so is any file over 20 MB. Tick file types under Download attachments filter to limit what is downloaded. Leave them all unticked to take every other attachment. Move email to folder files the message. Destination folder is a name or a path such as Receipts/Processed. Create the folder if it doesn't exist starts ticked. File each email once (group by email) is for after a loop, so one email with several attachments is moved once. Set categories stamps names such as Processed onto the message. Add (merge with existing) is the default. Replace existing overwrites the names already there. A name that is not in the mailbox's category list still appears on the message, without a colour until someone creates that category in Outlook.

What the step passes on. Find emails and Download attachments pass on one item per match or file. Get conversation and a single Send email pass on one item. Later steps reach their fields through Step data references, and an Intelligence step reads all of the items together. To reply to, move or download one message for each item from a list, put that step inside a Loop, described in Conditions, loops and approvals. Email received already starts one run per message, so the steps after it do not need a Loop for that one message.

As a tool for an Intelligence step. Connect an Outlook step to the Tools side of an Intelligence step and Actions becomes a searchable list where you can tick several. The AI decides when to call each one and fills in the fields itself. The canvas summary is the count, such as 3 actions enabled, not the action names.

Supplier invoices

Outlook · Inbox/Invoices

Draft the reply

GPT-5.6 Terra

Mail tools

3 actions enabled

1

1. 1The Outlook step attached to the Intelligence step as a tool.
2. 2Actions: the Outlook actions the AI may call. Here, send, draft and find.
3. 3Pause for approval: each call the AI makes waits for someone to approve it in the Runs panel.

Pause for approval appears on every Outlook step but only applies to calls an AI makes, so it has no effect on a step in the main flow. To ask someone before a main-flow step sends or moves mail, put an Approval step in front of it.

Outlook does not have its own webhook. Agents that should start when mail arrives use Email received, in the Trigger group of the Nodes panel. It watches one Outlook folder, or one Gmail label, and starts a run for each new message that passes the filters on the trigger. It uses the agent's Outlook connection, so if an Outlook step is already connected, the trigger can use that mailbox too. Setting up the folder, the filters, what the run receives and how to test it is covered in Start an agent when an email arrives. This section is only the part that belongs with the Outlook step.

Supplier invoices

Outlook · Inbox/Invoices

Reply to the supplier

1 action enabled

1. 1Connection on Email received. This is the same Outlook connection as the steps. Account appears when the agent has more than one mailbox.
2. 2Mailbox: Provider is Outlook, and Folder is the folder to watch. Inbox/Invoices watches that folder, not the folders inside it.
3. 3How do we decide this is the right email?: the filters. Open it on the trigger. The full guide is the Email received article.

What the next Outlook step can read. The trigger hands the new message to the next step: sender, subject, text, conversation id and a list of attachments. Reply to email can leave Message ID empty and it replies to that message. Get conversation can leave Conversation ID empty and it loads the thread. Download attachments takes the files. Move email to folder and Set categories file it afterwards. A filter that does not match does not start a run and does not use a credit. The trigger itself is free. Each run it starts costs 1 credit, like any other run.

Per-user mode does not apply. An arriving email has nobody behind it, so Integration mode is greyed out once Email received is the trigger, and the agent uses the mailbox connected on the agent. If the agent was previously set to Per-user, switch it back to Agent-level before you publish. Alerts only start runs once the agent is published. Run now works on a draft and uses the latest message in the folder.

Job finished

Job status changed

Fetch the job

Get job

Write the note

GPT-5.6 Terra

Email the customer

1 action enabled

Job completed email writes to the customer when a visit is finished. Job finished is a BigChange webhook with Job status changed ticked, and the status filter in BigChange set to the completed statuses. Fetch the job uses Get job, so the agent has the contact, the site and the engineer: for example job J-10482, a boiler service at Riverside House for Northgate Housing, with Dylan Hughes on the job. Write the note turns that into a short plain note. Email the customer is Send email, from accounts@meridianfm.co.uk, with To set to repairs@northgatehousing.co.uk and Body set to the note. Each finished job costs five credits or a little more. The BigChange side of this pattern is in BigChange REST in Agent Builder.

Each morning at 07:00

Daily at 07:00

Overnight mail

1 action enabled

Write the summary

GPT-5.6 Terra

Email the office

1 action enabled

Morning mail summary emails John Martin at 07:00 each day. Overnight mail uses Find emails with Within the last (hours) set to 24 and Folder left as the inbox, and passes on one item per message. Write the summary reads them together and groups them by sender, flagging anything with an attachment. Email the office is a second Outlook step, Send email, with To set to john.martin@meridianfm.co.uk and Subject set to Overnight mail. Both steps can use the same mailbox, or Email the office can pick a different one under Account. The search costs 1 credit however many messages it returns. The schedule is free. The run costs 1 credit on top.

Supplier invoices

Outlook · Inbox/Invoices

Check the invoice

GPT-5.6 Terra

Reply to the supplier

1 action enabled

File the email

1 action enabled

Reply to a supplier invoice answers mail that lands in Inbox/Invoices. The trigger watches that folder on accounts@meridianfm.co.uk, with From contains set to the supplier's domain and Has attachments set to yes, so a message with no file does not start a run. Check the invoice reads the message. Reply to the supplier uses Reply to email, with Reply body set to a short note that the invoice has been received, and Reply all left off, so only the sender is answered and the reply stays in the same conversation. File the email uses Move email to folder with Destination folder set to Filed invoices. Create the folder if it doesn't exist stays ticked. Each matching invoice costs four credits or a little more.

A dry run is the safe way to try an Outlook step. Open Runs in the toolbar, click Run now and choose Dry run (no actions performed). Read actions such as Find emails, Read email and Get message call Outlook for real, so you see real messages. Get message marks the message as read even on a dry run, because the read itself is a real call. Write actions, Send email, Reply to email, Create draft, Move email to folder and Set categories, are skipped. The step's summary starts with DRY RUN and says the email was not sent, and nothing in the mailbox changes. Run for real performs every action, including the writes.

{
  "handles": {
    "main": 4
  },
  "items": {
    "main": [
      {
        "subject": "Invoice 1842",
        "from": "invoices@harbourplant.co.uk",
        "receivedDateTime": "2026-10-08T16:40:00Z",
        "hasAttachments": true
      }
    ]
  }
}

Open a step in the run to see its output. The panel shows the first 50 items of each output, and later steps still receive all of them. A skipped send does not put a message in Sent. A dry run costs 1 credit for the whole run. For a published Email received agent, Run now uses the latest message in the folder and is a real run if you choose Run for real, so try the reply with a dry run first. For Run now, dry runs and the Runs panel in full, see Test an agent before it goes live.

An Outlook step costs 1 automation credit each time it runs successfully, whatever the action and however many messages Find emails returns. A step that fails costs nothing. When the step is a tool, each call the AI makes costs 1 credit. The Email received trigger and a schedule are free, but every run they start costs 1 credit, like any other run. Per-user does not change the price: Send email still costs 1 credit.

Inside a Loop, the step is charged on every pass, so a Loop over 40 messages that replies to each one costs 40 credits for that step. One Find emails is usually cheaper than fetching messages one at a time. For allowances, limits and how to see what each run cost, see Automation credits and usage limits.

• Two connections. The agent's mailbox and each person's Microsoft Outlook card in chat are separate. Connecting one does not connect the other. The email signature on that card is used when someone sends from chat. An agent sends the Subject and Body on the step, and does not add that signature.
• The signed-in mailbox only. The step uses the account chosen at Microsoft's account page. It does not offer a shared mailbox you can open but are not signed in as.
• No calendar actions. Sign-in asks for calendar access, but the 10 actions are all mail. Calendar questions belong in chat.
• Read limits. Read email returns at most 50 messages and defaults to 10. Find emails defaults to 25 and stops at 100. Get conversation defaults to 50 and stops at 100. A folder path does not include its child folders.
• Get message marks mail as read. A later step that looks for unread mail will not see it again. Get conversation, Find emails and Read email do not mark mail as read.
• Attachments. Download attachments skips inline images and any file over 20 MB (20,971,520 bytes). Send email and Reply to email can attach files from an earlier step, up to 20 files and 20,971,520 bytes unless you change the boxes, and never more than 50 files or 26,214,400 bytes. Create draft cannot attach files, and its To and Subject boxes are not on the panel.
• Per-user integration mode. Only Send email and Create draft, and only when a person starts the run from chat. A schedule has no person, so the step fails. The Account picker applies in Agent-level only. Settings lists the agent's mailboxes in Agent-level, and hides them in Per-user.
• Published agents only. Email received only starts runs once the agent is published. Run now works on drafts.

• Outlook not connected to this agent. Open the step's Connection section and click Connect. If you have duplicated the agent, the copy needs its own sign-in. A chat connection on the Integrations page does not count.
• Outlook account "primary" is no longer connected to this agent. The word in quotes is the account reference stored on the step, and it may be a longer id for a mailbox you added later. The Account list also warns This node's account is no longer connected to this agent. Choose Primary account (default) or another mailbox, or sign that one in again.
• Save this workflow as a draft first, then connect the account. Click Save draft, then Connect.
• Failed to start Outlook connection. Centrus could not open Microsoft. Try Connect again.
• The action is not supported in per-user mode. The agent is on Per-user, and the step is not Send email or Create draft. Switch Integration mode to Agent-level, or change the step to one of those two actions. The message names an internal action id. You can ignore the id and use the action's name from Actions.
• This run has no triggering user. Per-user was left on, and a schedule or Email received started the run. Set Agent-level. The control is greyed out on those triggers, so if you cannot change it, put a Chat Trigger on the canvas for a moment, switch the mode, then put the original trigger back.
• This step needs your own Outlook connected. In Per-user, the person who started the run has not connected Microsoft Outlook on the Integrations page. They connect it there, then run again. Check my own connection on the step tells you whether yours is connected.
• An empty reply was not sent. Reply body is required. Paste the text, or a reference to an earlier step.
• Message not found or has been deleted. Get message could not open that id. The message may have been moved, which changes its id. Use the id from the step that just fetched it, or Find emails again.
• No actions selected. The step has no action yet. Choose one under Actions.
• Create draft has nowhere to type the address. Those boxes only appear for Send email. Use Send email, or attach Create draft to an Intelligence step as a tool.
• An email never starts the agent. Email received must be the trigger, the agent must be published, Provider must be Outlook, and Folder must be the folder the mail actually lands in. Check the filters in Start an agent when an email arrives.
• A list stops early. Read email stops at 50, Find emails at 100, Get conversation at 100. Narrow the folder or the time window rather than expecting the whole mailbox.

The Outlook step has 10 actions. Five read the mailbox and five change it. They call Microsoft Graph at https://graph.microsoft.com/v1.0, as the mailbox you connected on the agent, or, for Send email and Create draft in Per-user mode, as the person who started the run. Reply all uses POST /me/messages/{id}/replyAll instead of the reply path below.