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Claude for Microsoft 365

Claude for Microsoft 365 is Anthropic's official addin for Word, Excel, PowerPoint, and Outlook. By pointing it at a running Tresor instance, you can keep the Anthropic client experience while hot-switching the underlying model between Anthropic, DeepSeek, MiniMax, a local llama.cpp server, or any other configured downstream — all from the web UI.

No need to worry about the different API format underlying model is using, Tresor will auto-translate between the Anthropic API (Claude Desktop) to other API formats (e.g., gpt-5.5 using OpenAI Responses).

This page shows how to wire Claude for Microsoft 365 to Tresor.

✅ Prerequisites​

1. Configure Tresor​

There are two ways to prepare Tresor:

1.1 Option 1: via Web UI​

Web UI is more intuitive, but require more manual operations.

  1. In "Downstreams" tab

    • Click + Add Provider to add the LLM provider you are about to use.

  2. In "Aliases" tab

    • Click + New Alias Group

      • Input Model ID: claude-opus.*
      • Checked "Regex Pattern"
      • Select the Downstream and Output Model IDs you added previously.

    • Repeat the above add new alias group process to add claude-sonnet.* and claude-haiku.*

    • Click + Add Name:

      • For alias claude-opus.*: Add announced name claude-opus
      • For alias claude-sonnet.*: Add announced name claude-sonnet
      • For alias claude-haiku.*: Add announced name claude-haiku

      WARNING: Unlike Claude Code's setup guide, announced names are required to allow Claude for Microsoft 365 to detect available models!

  3. In "Settings" tab

    • Click + Add API Key under "Proxy Authentication" section (e.g, sk-proxy-123). Copy it, and we are about to fill it into ANTHROPIC_AUTH_TOKEN in the following section.

1.2 Option 2: via config.yaml​

Editing yaml is less intuitive, but require less manual operations.

The following example config.yaml uses 3 downstream providers. Replace them based on your actual providers.

~/.config/tresor/config.yaml
bind_addr: 127.0.0.1:11510
proxy_api_keys:
  - sk-proxy-123
... # Omitted showing other settings here
downstreams:
    - id: llama-cpp
      name: llama.cpp
      base_url: http://127.0.0.1:3000 # change to your actual llama.cpp listening port
      api_formats:
        - openai
        - anthropic
      output_model_ids:
        - qwen3.6:27b-mtp-coder
        - qwen3.6:27b-mtp:instruct
    - id: deepseek
      name: DeepSeek
      base_url: https://api.deepseek.com/anthropic
      api_formats:
        - anthropic
      output_model_ids:
        - deepseek-v4-flash
        - deepseek-v4-pro
    - id: minimax
      name: MiniMax
      base_url: https://api.minimaxi.com/anthropic
      api_formats:
        - anthropic
      output_model_ids:
        - MiniMax-M2.5
        - MiniMax-M2.7
        - MiniMax-M3
aliases:
    - input_model_id: claude-opus.*
      is_regex: true
      announced_names:
        - claude-opus
        - claude-opus-5
      options:
        - id: alias-minimax-m3
          downstream_id: minimax
          output_model_id: MiniMax-M3
        - id: alias-deepseek-pro
          downstream_id: deepseek
          output_model_id: deepseek-v4-pro
    - input_model_id: claude-sonnet.*
      is_regex: true
      announced_names:
        - claude-sonnet
        - claude-sonnet-5
      options:
        - id: alias-llama-cpp-qwen-instruct
          downstream_id: llama-cpp
          output_model_id: qwen3.6:27b-mtp:instruct
        - id: alias-deepseek-flash
          downstream_id: deepseek
          output_model_id: deepseek-v4-flash
        - id: alias-minimax-m2-7
          downstream_id: minimax
          output_model_id: MiniMax-M2.7
    - input_model_id: claude-haiku.*
      is_regex: true
      announced_names:
        - claude-haiku
        - claude-haiku-4-5
      options:
        - id: alias-minimax-m2-5
          downstream_id: minimax
          output_model_id: MiniMax-M2.5

If a not-announced name like claude-opus-4-8 requests Tresor, the most precisely matched alias will still handle it (in this case, claude-opus.*). Optional announced names does not limit the capability of regex alias group's model name matching.

Restart Tresor to apply the changes in yaml.

2. Configure Claude for Microsoft 365​

Launch one of the office apps (Word, Excel, PowerPoint, or Outlook), click Cloud provider or gateway

In Gateway section:

FieldValue
Gateway URLhttp://127.0.0.1:11510
TokenOne of your Tresor API key in proxy_api_keys field (e.g., sk-proxy-123)

Click Continue. It will test the connectivity of all models that starts with `claude-, so make sure they are reachable. Once succeeded:

All other office apps will synchronize this setting, so you don't need to configure others one by one.

3. Hot-switch from the web UI​

Open http://127.0.0.1:11510 in a browser, go to the Aliases tab, and click any sibling option card to make it active. Claude for Microsoft 365's next request will be routed to the new downstream — no restart of either Tresor or Claude for Microsoft 365 is required. 🎉

For example, flip claude-sonnet from deepseek-v4-flash to MiniMax-M2.7 with a single click, and the agent immediately starts using MiniMax on the following turn.

📚 See also​