WinSCP has its own Agent forwarding setting, which overrides the PuTTY default:
https://winscp.net/eng/docs/ui_login_authentication

I have no problems using agent auth with Pageant from Putty launched with Ctrl+P from WinSCP.

However, it looks like there's more to your command line there - what is the full command? I notice a '!' at the end there?

Also it might be worth it to try to add -A to enable Agent forwarding although it's not really the same thing
https://the.earth.li/~sgtatham/putty/latest/htmldoc/Chapter3.html#using-cmdline-agent

Try to enable some debugging in Putty to see what goes on underneath.

I am using
Windows7x64
Winscp 5.9.4
Putty 0.68
Pageant 0.68

I configured a host which can be successfully connected via SFTP.
winscp works like it should.

For this host I want putty (which I open via "open putty session" from winscp) to activate "agent forwarding".
So I adjusted the Putty default settings to use "agent forwaring".

when opening the session via putty (_not_ initiated via winscp), the default settings work for me and also the "agent forwarding" is active.
when doing the same in a putty session which was opened from winscp, it doesnt work.


I did some "debugging":
- loading the "WinSCP temporary session" from standalone putty, after I used it in winscp before shows me that the temporary session does not use "agent forwarding".

does this mean winscp does not take this setting from the putty defaults?