You can go look at his GitHub but it's a bewildering array of projects. I've had a bit of a poke around at a few of the seemingly more recent ones. Bit odd though as in one he's gone heavy on TS classes and another heavy on functions. Might be he was just contributing to one as it was under a different account.
And a lot of them seem to be tools that wrap a lot of cli tools. There is a ton of scaffolding code, to handle a ton of cli options. A LOT of logger stmts, one file I randomly opened was a logger stmt every other line.
So it's hard to judge, I found it hard to wade through the code as it's basically just a bunch of option handling for tool calls. It didn't really do much. But necessary, probably?
Just very different code than I need to write.
And there are some weird tells that make it hard to believe.
For example, he talks about refactoring for useEffect in React but I KNOW GPT5 is really rubbish at it.
Some code it's given me recently was littered with useEffect and useMemo when it wasn't needed. Then when challenged it got rid of some, then changed other stuff to useEffect when again, it wasnt needed.
And then got all confused and basically blew it's top.
Yet this person says he can just chuck a basic prompt at his codex cli, running GPT5 and it magically refractors the bad useEffects?
How are we getting such different results?