@yao thanks for reply
the bletool from linked GitHub repo is exactly what I used. I actually had to remove the gl-bletool-api (which I believe is used by the Admin Panel) to make the Bletool work.
So it can discover, list local address etc but somehow it does not connect to the device.
Any hints on what to use to troubleshoot the connection issue?
In meantime I used the Admin Panel cgi endpoints to connect to the device. Will it be considered safe choice to rely on the cgi api instead?