I checked out William Vincent’s The Secret Prompts in GitHub Copilot CLI tonight, and I wanted to share a few tips and what stood out to me. GitHub Copilot CLI uses Claude Sonnet 4.5 by default No luck other than confirming it is using Claude models by default. Apparently, you can change the underlying model, for example, to ChatGPT 5, by updating the environment variable COPILOT_MODEL=gpt-5; however, we will work with the defaults here. You can Copilot CLI’s default model via the /model ...
