This is a continuation and completion of https://4gfj4hgkj4as4.pages.dev/t/topic/96870. 
Features:
Full Copilot conversational capabilities — Streaming/non-streaming, multi-turn dialogue, deep reasoning
OpenAI-compatible API — Directly plug into existing OpenAI ecosystem tools by simply replacing the base_url
Anthropic Messages compatible — Supports the /v1/messages endpoint as well
Model switching — Auto / Quick / Reasoning / GPT-5.2-5.5 / Claude_Sonnet†
Encrypted credential storage — Refresh token is saved to disk using AES-128-CBC encryption
Zero browser dependency — Token refresh bypasses SPA restrictions via Origin Spoofing
Claude_Sonnet tag is accepted by the server, but on the backend it actually routes to GPT-5.
In theory, supports unlimited GPT-5 calls. And it’s directly accessible from within China, with no blocks. 
Project page: GitHub - HEXUXIU/M365-Copilot2API: Access M365 Copilot via CLI & OpenAI-compatible API · GitHub
If this project is helpful to you, feel free to give it a Star 
btw, I’ve noticed many folks are failing to acquire tokens. You can check out this project for reference: GitHub - lezi-fun/m365-copilot-client · GitHub (the README for this project looks much better than mine)
