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Claude for Office is Anthropic’s Microsoft 365 add-in that brings Claude directly into Word, Excel, PowerPoint, and Outlook. By routing Claude for Office through Bifrost, you get governance features like virtual keys, budget controls, rate limits, and built-in observability for all office-based AI usage across your organization. Claude for Office with Bifrost

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Setup

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1. Install the Add-in

Install the Claude for Office add-in from the Microsoft AppSource marketplace within any Office application (Word, Excel, PowerPoint, or Outlook). Organization admins can also deploy it centrally via the Microsoft 365 admin center.

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2. Log in and Select Enterprise Gateway

Open the Claude for Office add-in and log in to your account. On the login screen, select Enterprise Gateway as your connection method.

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3. Configure the API Endpoint

Enter your Bifrost endpoint as the Base URL: 
https://bifrost.example.com/anthropic
For local development: 
http://localhost:8080/anthropic

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4. Set Your API Key

Enter your Bifrost virtual key or Anthropic API key in the API Key field.

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5. Whitelist Required Headers

If your Allowed Headers are already set to *, you can skip this step.
Claude for Office requires the following headers to be in the Allowed Headers list. Go to Settings > Client Settings and add them as a comma-separated list: 
anthropic-dangerous-direct-browser-access, anthropic-version, content-type, user-agent, x-api-key, x-stainless-arch, x-stainless-helper-method, x-stainless-lang, x-stainless-os, x-stainless-package-version, x-stainless-retry-count, x-stainless-runtime, x-stainless-runtime-version, x-stainless-timeout
You’re all set — Claude for Office will now route all requests through Bifrost.

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How It Works

Claude for Office uses the Anthropic Messages API natively. Bifrost exposes a fully compatible Anthropic API at the /anthropic path, so the add-in works without any additional configuration beyond pointing it at your Bifrost instance. Bifrost automatically handles:
  • Model routing — requests are routed to the correct provider based on the model name
  • Tool stripping — server-side tools like code_execution, web_search, and web_fetch are automatically stripped to prevent API conflicts
  • Model metadata — token limits and capabilities are returned in list models responses for proper model selection in the add-in

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Using Virtual Keys

Bifrost Virtual Keys can be used as the API key in Claude for Office. This lets you:
  • Enforce per-user or per-team budgets and rate limits
  • Control which models and providers each user can access
  • Track usage and costs across your organization
  • Rotate credentials without updating every user’s add-in configuration
For organization-wide deployments, create separate virtual keys for each team or department to manage AI spend independently.

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Observability

All Claude for Office requests through Bifrost are logged. Monitor them at http://localhost:8080/logs — filter by provider, model, or search through conversation content to track usage patterns across your organization.

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Next Steps