Does it pass the Turing test?
that would be a reasonable definition of AGI if everyone agree upon the specifics of the test, but that has never happened. Turing test is very much out of style, but I think that's because no one could even agree what the test was. I personally like the Kurzweil-Kapor version of the test and that is still unsettled: https://longbets.org/1/
Depending on the proctor, ELIZA passes a Turing test. The Turing test is an interesting thought experiment, but isn't really a good measure.