3.agenix/doc/overriding-age-binary.md

Overriding age binary

The agenix CLI uses age by default as its age implemenation, you can use the rage implementation with Flakes like this:

{
  pkgs,
  lib,
  agenix,
  ...
}:
{
  environment.systemPackages = [
    (agenix.packages.x86_64-linux.default.override { ageBin = lib.getExe pkgs.rage; })
  ];
}

Please note that the behavior of alternative implementations may not match that required for agenix to function, and the agenix team does not plan to provide support for bugs encountered when using agenix with nondefault implementations.