Outlook add-in

The Outlook add-in brings the AI colleague into the inbox as a side pane. The open message serves as the context. This page describes the feature set, how attachments are handled, the sign-in and the route for distribution inside the company.

The add-in is our own development.

What it can do

• Summarize the open mail, including long threads.
• Write a draft reply that lands in the normal Outlook reply window.
• Pull tasks and deadlines out of a message.
• Read files and attachments along the way, see below.
• Adopt your writing style on request, if the admin has set that up.

It runs in Outlook for Windows, for Mac, on the web and in the new Outlook.

It never sends automatically

The add-in delivers text. The draft lands in the native reply window, and you are the one who sends it. There is no automatic sending, and the corresponding Microsoft permission to send is deliberately not requested.

It is not a side route around the platform

Behind the pane, a real agent runs on your server, in the same instance as the web chat. That has three consequences for administrators:

Permissions	The same roles and the same rules for connectors apply as in the web chat
Usage	Every turn is metered and appears in usage and billing
Log	Connector calls appear in the audit log, as everywhere else

No model traffic runs past the platform.

Files and attachments

The pane reads files itself and only sends on the text. The file does not leave your machine.

Format	What is read
PDF	Text per page, no OCR
Word .docx	Paragraphs including table cells and line breaks
Excel .xlsx	Sheet name and rows, gaps between columns are preserved
Text .txt .md .csv .tsv .json .log .yml .xml	raw text
Images JPEG and PNG	as an image attachment, scaled down before sending

Upper limits for number, size and amount of text apply per message. When a limit is reached, the pane tells you instead of silently leaving something out.

Not read are the old binary formats .doc, .xls and .ppt, PowerPoint, archives, cloud attachments (only a link arrives there) and attached emails. In these cases too the pane names the reason.

Files reach the conversation in three ways: through the menu in the input field, by dragging onto the chat area and, for images, through the clipboard.

Scanned attachments need a text layer

A scanned PDF without a text layer contains no readable text. The pane reports that explicitly instead of producing an empty summary.

Attachments of the open mail

The attachments of the open message are never read unasked. If the mail has attachments, a card halts the process after sending and lets you choose individually what may be read. On request the pane remembers the choice for this one email.

For that the Outlook client needs a sufficiently recent version of the mailbox interface. If it is too old, the card says so and the process continues without attachments.

Personal instructions

The settings of the pane contain a field for personal specifications, for example “immer Sie, nie Gedankenstriche, Grussformel Freundliche Grüsse” (always the formal address, never dashes, closing Freundliche Grüsse). These specifications sit at the very top of the hierarchy: they beat skills, the writing style profile and the instructions of the agent.

They are formed fresh from the settings on every send and are not stored in the history. If you change them in the middle of a conversation, the new version applies immediately.

Sign-in without a password

The pane does not ask for a password. Instead, sign-in runs through a device code:

1. In the pane press “Anmelden” (sign in). A short code appears.

2. “Im Browser fortfahren” (continue in the browser). A confirmation page opens there on your own chat domain, showing the same code.

3. Click “Verbinden” (connect). The page uses your existing browser sign-in. If you are not signed in in the browser, the page offers the login and the code stays valid.

4. The pane completes the connection itself.

The process expires after a short time. At the end the pane receives exactly one value: your personal key named “Outlook-Add-in”. It is valid for a limited period and can be revoked at any time, in the settings of the web chat under “API-Schlüssel für Agenten” (API keys for agents).

The advantage of this route: two factor sign-in and, later, Entra sign-in work without extra effort, because the browser login already covers it.

One limit you should know about

Answers from the pane do not appear in the web chat

What you discuss in the Outlook pane does not show up in the history of the web chat. The history lives in the pane. That is a known limitation of the interface through which external clients are connected.

Usage metering and logging still apply in full. So there is no gap in cost and traceability, there is simply no second conversation history.

For admins: prerequisites

Prerequisite	Detail
Publicly valid TLS	Office loads publicly trusted HTTPS only. An internal certificate authority is not enough, the pane would stay empty
Mailboxes on Exchange Online	POP3, IMAP and on premises Exchange are not supported by the add-in platform. There is no way around this
Admin rights in Microsoft 365	Role “Global Administrator” or “Exchange Administrator”
Reachable chat domain	The pane addresses the same domain as the web chat

Answers have to be streamed continuously

If the response stream is buffered instead of sent continuously, the Outlook display window aborts after a short time with “no connection”, even though everything on the server side is running correctly. What is affected is exactly the long, tool heavy answers you want the add-in for in the first place. The default is set correctly; it should not be changed.

For admins: setup

1. Provide the add-in so that it is served under your chat domain.

2. Create the agent. Create an agent in the chat, for example with the name Outlook-Assistent, with the customer’s default model and initially without connectors.

3. Grant the agent remote access. Without that grant the interface refuses access. In addition the role permission “Remote-Agenten” (remote agents) has to be set for the roles that are meant to use the add-in.

4. Store the default agent so that nobody has to select it in the pane.

5. Check the manifest. It must no longer contain a placeholder.

Distribution in the Microsoft 365 admin center

1. Open admin.microsoft.com, then Settings → Integrated apps.

2. Upload custom apps, then Office Add-In and Upload manifest file.

3. Assign to Just me for testing, to individual Users/groups for a pilot or to the Entire organization for the rollout. Confirm permissions and deploy.

Count on 24 hours

According to Microsoft it takes up to 24 hours until the add-in appears in the ribbon for all users. Classic Outlook has a local cache on top of that.

For a pilot, the route through aka.ms/olksideload is considerably faster. It works per mailbox and takes effect immediately on all clients of that mailbox.

For updates, increase the version number in the manifest and update it under Integrated apps. The GUID always stays the same. A new GUID counts as a different add-in and would appear a second time in the ribbon.

Optional: adopting the writing style

If the pane should learn your personal writing style from sent mail, it needs its own app registration in Entra with a delegated read permission on the mailbox. Without this step the add-in works completely, only the style adoption is missing. The access token stays in the client and does not go to your server. A permission to send is deliberately not requested.

Troubleshooting

Symptom	Cause and solution
Add-in does not appear in the ribbon	Distribution takes up to 24 hours. Test immediately through sideload. Restart classic Outlook
Pane stays white	Check the certificate. It needs a publicly valid one, not an internal certificate authority
Pane empty only in Outlook on the web	The pane must not be blocked by framing headers
Access to the agent is refused	The remote access grant for the agent is missing, or the role permission is off
Sign-in demanded while chatting	The personal key has expired. Sign out in the pane and sign in again
Abort on long answers	The response stream is buffered instead of being sent continuously
Add-in missing for individual people	Their mailbox is not on Exchange Online

Errors from the pane additionally land in the admin panel under “Logs”, tab “Client-Fehler” (client errors). The technical cause is listed there with person, platform and file name, never a file content. The entries are removed automatically once the retention period has passed.