Install Office LLM Assistant

Self-hosted add-in for Word, Excel, PowerPoint, and Outlook

Windows installer

Download the installer and run it. The installer downloads the add-in manifest, registers it for the selected Office app, and appears in Installed Apps so it can be uninstalled later.

Download llm-assistant-setup.exe Download manifest.xml only

First time only — SmartScreen: Because the installer is downloaded from the internet, Windows may show a SmartScreen warning. Click More info, then Run anyway. No administrator rights are required.

The installer shows a page where you can choose which Office apps receive the add-in. All four (Word, Excel, PowerPoint, Outlook) are selected by default. You can also run the installer silently from Command Prompt or PowerShell with parameters like /SILENT /TASKS="installword,installexcel", or quietly with /VERYSILENT /NORESTART. To uninstall, use Settings → Apps → Installed apps (the entry is named “Office LLM Assistant”) — or from a command line, find the uninstall string under HKCU\Software\Microsoft\Windows\CurrentVersion\Uninstall\ and run it with /SILENT.

The installer stores the add-in in your personal profile (%LOCALAPPDATA%\OfficeAddins\OfficeLLM) and does not create Start Menu or Desktop shortcuts.

macOS installer

Open Terminal and run this one command — it installs the add-in for Word, Excel, PowerPoint, and Outlook in a single step (no need to pick an app):

curl -fsSL /llm-assistant-setup-mac.sh | bash

The script downloads the manifest(s), installs them into each Office app's sideload folder, clears the web cache, and launches the apps. No chmod or administrator rights required. To install for a single app only, add the app name: ... | bash -s -- word (or excel, powerpoint, outlook).

Download the script instead

Advanced: manual download, uninstall, force reinstall

Manual download: Download the script, make it executable, and run it:

chmod +x ~/Downloads/llm-assistant-setup-mac.sh
~/Downloads/llm-assistant-setup-mac.sh

Uninstall (removes from all four apps):

curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- --uninstall

Force reinstall (even if the version is the same):

curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- --force

The installer copies the manifest into ~/Library/Containers/com.microsoft.Word/Data/Documents/wef/ (and the Excel/PowerPoint/Outlook equivalents). Word/Excel/PowerPoint use the TaskPaneApp manifest (manifest.xml); Outlook uses a separate MailApp manifest (manifest-outlook.xml). The script auto-detects the server origin and trusts the server's certificate if needed (dev servers only).

Manual install (Windows)

Close all Office applications.
Download manifest.xml and save it to %LOCALAPPDATA%\OfficeAddins\OfficeLLM\manifest.xml.
Delete the Office cache folder: %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\
Register the manifest by creating the flat registry value (used by Word, Excel, and PowerPoint):
```
reg add "HKCU\Software\Microsoft\Office\16.0\WEF\Developer" /v "5c6e7f8a-9b0c-1d2e-3f4a-5b6c7d8e9f0c" /t REG_SZ /d "%LOCALAPPDATA%\OfficeAddins\OfficeLLM\manifest.xml" /f
```
The same value is read by Word, Excel, and PowerPoint; there is no per-host subkey.
Open Word/Excel/PowerPoint. The Office LLM group should appear on the Home tab.

Outlook (optional): Outlook uses a separate MailApp manifest. Download manifest-outlook.xml to %LOCALAPPDATA%\OfficeAddins\OfficeLLM\manifest-outlook.xml and register it under its own Id:

reg add "HKCU\Software\Microsoft\Office\16.0\WEF\Developer" /v "e7f8a9b0-1c2d-3e4f-5a6b-7c8d9e0f1a2b" /t REG_SZ /d "%LOCALAPPDATA%\OfficeAddins\OfficeLLM\manifest-outlook.xml" /f

Classic Outlook (OUTLOOK.EXE): loads the add-in from this registry entry — no bootstrap document needed. Open Outlook and look for the Office LLM group when reading or composing an email.

New Outlook for Windows (olk.exe): The registry method does not work — the new Outlook (Microsoft.OutlookForWindows appx) syncs add-ins from your Exchange mailbox, not the registry. The installer detects it and opens the Add-Ins for Outlook dialog automatically. In the dialog: My add-ins → Custom Addins → Add from File → select manifest-outlook.xml. You can also open the dialog manually via https://aka.ms/olksideload.

Which Office app?

Windows: run llm-assistant-setup.exe and keep Word selected. macOS: curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- word. After running, open Word and look for the Office LLM → New Chat button on the Home tab.

Windows: run llm-assistant-setup.exe and keep Excel selected. macOS: curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- excel. After running, open Excel and look for the Office LLM → New Chat button on the Home tab.

Windows: run llm-assistant-setup.exe and keep PowerPoint selected. macOS: curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- powerpoint. After running, open PowerPoint and look for the Office LLM → New Chat button on the Home tab.

Windows: run llm-assistant-setup.exe and keep Outlook selected. macOS: curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- outlook. Outlook uses a separate MailApp manifest (manifest-outlook.xml, different add-in Id) and does not need a bootstrap document — it loads the add-in directly from the registry (Windows) or the wef folder (macOS). After running, open Outlook and look for the Office LLM group on the Home/Message tab when reading or composing an email.

New Outlook for Windows (olk.exe): The registry/wef method works for classic Outlook only. If the installer detects the new Outlook (Microsoft.OutlookForWindows appx), it automatically opens the Add-Ins for Outlook dialog (https://aka.ms/olksideload) in your browser. There, choose My add-ins → Custom Addins → Add from File and select manifest-outlook.xml. The add-in syncs to your Exchange mailbox and appears in both new and classic Outlook after a restart. See the official sideload guide.

Troubleshooting

Add-in does not appear (macOS): Close all Office apps and re-run curl -fsSL /llm-assistant-setup-mac.sh | bash -s -- --force — the --force flag re-installs and clears the web cache.
Add-in does not appear (Windows): Close all Office apps, delete the Wef cache folder (%LOCALAPPDATA%\Microsoft\Office\16.0\Wef\), and run the installer again.
Certificate warning (dev servers only): If you see a certificate warning, ensure you are accessing this page via the correct HTTPS URL (the one in your browser's address bar). Production uses a Let's Encrypt certificate. Dev servers use a self-signed certificate — the macOS installer and Windows installer both trust it automatically.
SmartScreen warning: Click More info, then Run anyway. The installer is not signed with a public code-signing certificate, so Windows Defender SmartScreen may prompt the first time.
Need to reinstall after an update: Re-run the installer. The manifest version is bumped on every release.
Add-in does not appear in the new Outlook (olk.exe): The new Outlook for Windows (Microsoft.OutlookForWindows appx) does not read the Wef\Developer registry. Sideload via the Add-Ins for Outlook dialog instead: go to https://aka.ms/olksideload → My add-ins → Custom Addins → Add from File → select manifest-outlook.xml. The installer does this automatically if it detects the new Outlook and opens the dialog in your browser.
Dev + prod coexist (macOS): The dev macOS installer writes office-llm-dev.xml / office-llm-outlook-dev.xml into the wef folder; the prod installer writes office-llm-assistant.xml / office-llm-outlook.xml. They use different manifest Ids, so both can be installed side by side.