And I've had a brief try myself. The interface, /help and even copilot --help show nothing about which model you're using or how to switch between them. There's no /model command. Thankfully Simon describes that. The fact that you can't switch to a model that Copilot normally offers unlimited usage of, such as GPT-4.1, is very disappointing. (I tried it and it didn't work, doesn't even print an error for invalid model ID.)
It seems that they wrote this from scratch as it's missing the features you'll find in any other CLI tool such as opencode, crush, Claude Code, etc. It's a little bit bare. The interface is somewhat different and better or worse in some ways. It's good that it uses normal terminal scroll-back instead of hiding it, but you can still expand/collapse tool outputs. Really wish I could expand a single one though. Viewing outputs of running tools live glitches up the terminal UI, at least in xfce4-terminal.
Instead of showing you how much of the context window remains like some other CLIs, it shows how many requests you have remaining this month.
> By default, copilot utilizes Claude Sonnet 4. We also support GPT-5 via an environment variable. Run COPILOT_MODEL=gpt-5 copilot to launch in GPT-5 mode. Or on Windows, run set COPILOT_MODEL=gpt-5 before running copilot.
Has anybody actually tried it yet?
Yes: https://simonwillison.net/2025/Sep/25/github-copilot-cli/
And I've had a brief try myself. The interface, /help and even copilot --help show nothing about which model you're using or how to switch between them. There's no /model command. Thankfully Simon describes that. The fact that you can't switch to a model that Copilot normally offers unlimited usage of, such as GPT-4.1, is very disappointing. (I tried it and it didn't work, doesn't even print an error for invalid model ID.)
It seems that they wrote this from scratch as it's missing the features you'll find in any other CLI tool such as opencode, crush, Claude Code, etc. It's a little bit bare. The interface is somewhat different and better or worse in some ways. It's good that it uses normal terminal scroll-back instead of hiding it, but you can still expand/collapse tool outputs. Really wish I could expand a single one though. Viewing outputs of running tools live glitches up the terminal UI, at least in xfce4-terminal.
Instead of showing you how much of the context window remains like some other CLIs, it shows how many requests you have remaining this month.
Nobody ever reads the docs lol
> By default, copilot utilizes Claude Sonnet 4. We also support GPT-5 via an environment variable. Run COPILOT_MODEL=gpt-5 copilot to launch in GPT-5 mode. Or on Windows, run set COPILOT_MODEL=gpt-5 before running copilot.