Remote mode fails on Windows ARM64 (win_arm64) — cryptography/cffi build error

[Ekqrd]

Running Windows 11 on ARM64 (Snapdragon). Remote mode is configured correctly
(Sandbox ID + API Key filled in), but the extension keeps trying to build
cryptography and cffi locally, which fails with:

Unsupported platform: win_arm64

The extension should NOT need local Python builds when running in remote mode.
Please add ARM64 support or skip local builds entirely when mode is set to "remote".

[Jeomon]

Let me check

[Jeomon]

@Ekqrd
I have pushed the changes plz clone the repo and if all goes well i will make a new release

[Ekqrd]

Hi @Jeomon , thank you for the quick response!

I cloned the repo and tested with the latest changes, but unfortunately the issue persists. Both the extension version and the manually configured version (pointing to C:\Users\david\Windows-MCP) still fail with the same error:

Python reports SOABI: cp313-win_arm64
Unsupported platform: win_arm64

Failed to build cryptography==45.0.4
Failed to build cffi==1.17.1

The root cause seems to be that even in remote mode, the code still tries to build cryptography/cffi locally from source, which requires ARM64 wheels or Rust — neither of which are available on win_arm64 with Python 3.13.

Possible fixes:

1. Skip the cryptography/authlib dependency entirely when MODE=remote (since authentication is handled server-side)
2. Pin cryptography to a version that has pre-built ARM64 wheels
3. Replace authlib with an ARM64-compatible alternative

System info: Windows 11 ARM64 (Snapdragon), Python 3.13.12 cp313-win_arm64, uv latest via winget.

Happy to test any new fix!

[Jeomon]

Can pull the changes and try again

[Ekqrd]

Still the same error after git pull. The cryptography dependency still fails on win_arm64.
Looking forward to a proper fix when ready!

[Jeomon]

@JezaChen I tried to fix it, but it didn't work, is there any other alternate approaches

[JezaChen]

I don't have a Windows ARM machine on hand at the moment😆. I'll try to set up an ARM virtual machine to reproduce the issue and look for a solution.

[JezaChen]

I tested this on an ARM virtual machine and confirmed that cryptography and cffi fail to install on native ARM Python. This happens because these upstream libraries lack ARM64 wheels for Windows, leading to Windows-MCP build failures. So, for Windows ARM64 users, please use x64 Python (cpython-3.13.12-windows-x86_64-none) instead of native ARM Python (cpython-3.13.12-windows-aarch64-none) to install Windows-MCP. Windows on ARM handles x64 emulation well, and the x64 ecosystem has full library support.