If it's useful, I recently open-sourced a simple GPT-4 TUI [1], which I use many times a day. And since this is a Kagi post, I might as well plug my (extremely simple) Kagi CLI [2], which uses their FastGPT API under the hood.
[1] https://git.sr.ht/~bsprague/gpt4-tui
[2] https://github.com/bcspragu/kagi