Archived. I've been using benpye/wsl-ssh-pageant.
Similar to benpye/wsl-ssh-pageant and NZSmartie/wsl-ssh-pageant, this allows Linux programs running under WSL to access PuTTY's Pageant SSH authentication agent, or some other compatible agent such as GPG4Win's gpg-agent (when configured with enable-putty-support).
The difference is this one is written in Rust and provides a similar command interface so it can be registered in your ~/.bash_profile the same as OpenSSH's ssh-agent:
if [ -z "$SSH_AUTH_SOCK" ] ; then
eval `<path to wsl-ssh-pageant> -s`
fi
Note: if you do not already have a ~/.bash_profile, you should include . ~/.bashrc in your profile or you will lose some of the default settings, at least on Ubuntu.
wsl-ssh-pageant-windows.exe must be placed in the same folder as wsl-ssh-pageant, and this folder must be on a drvfs mount such as /mnt/c so the Windows component can be executed.