Install

Whichever way you install it, keep one agent per session: disable the polkit agent the session started before.

With home-manager

The flake exports a home-manager module, for NixOS or any other distribution with nix:

{
  inputs.lys-polkit.url = "github:stubbedev/lys-polkit";

  # in the home-manager configuration
  imports = [inputs.lys-polkit.homeManagerModules.default];
  services.lys-polkit.enable = true;
  # one agent per session: drop the one it replaces
  services.hyprpolkitagent.enable = false;
}

It installs the package and the lys-polkit.service user unit, wanted by graphical-session.target.

On NixOS, security.polkit.enable = true provides polkitd and polkit 127's helper socket, which lys-polkit uses. On another distribution polkit 127's socket is used too, and an older polkit's setuid helper is found at /usr/lib/polkit-1/polkit-agent-helper-1.

Without nix

You need the Go version go.mod declares. Build, install the binary and the user unit, and enable it for the graphical session:

git clone https://github.com/stubbedev/lys-polkit
cd lys-polkit
go build -ldflags "-X main.version=$(git describe --always)" -o lys-polkit .
install -Dm755 lys-polkit ~/.local/bin/lys-polkit
mkdir -p ~/.config/systemd/user
sed "s|@bindir@|$HOME/.local/bin|" dist/lys-polkit.service.in > ~/.config/systemd/user/lys-polkit.service
systemctl --user daemon-reload
systemctl --user enable --now lys-polkit.service

Then check that it works.