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My notes on Gemini CLI, including poking around in their system prompt which I've extracted into a more readable rendered Gist simonwillison.net/2025/Jun/25/...

simonwillison.netGemini CLIFirst there was Claude Code in February, then OpenAI Codex (CLI) in April, and now Gemini CLI in June. All three of the largest AI labs now have their own …

25/6/25, 5:55 pm11 reposts81 likes

Christian Ströbele

@cstroebele.bsky.social

25 June 2025

very cool indeed. and (cf. gemini-cli/docs/core/tools-api.md: define a `toolDiscoveryCommand` in `settings.json`...) we can even bring our own tools!

Miguel Carvalho

@miguelcarvalho.xyz

25 June 2025

"- **Websites (Frontend):** React (JavaScript/TypeScript) with Bootstrap CSS, incorporating Material Design principles for UI/UX." Not sure how I feel about this. It's probably it's a good advice since Bootstrap has for sure more training data than something like Shadcn.. but still!?!

Simon Willison

@simonwillison.net

25 June 2025

Here's that system prompt - Gemini CLI is Apache 2 licensed so this is a neat open source example of a prompt for one of these terminal agents gist.github.com/simonw/9e5f1...

gist.github.comgemini-cli.mdGitHub Gist: instantly share code, notes, and snippets.

Nimo 🏳️‍🌈

@nimobeeren.com

25 June 2025

I also don’t fully get why agent CLIs are so popular. Can they do anything that agent IDEs can’t? The only benefit I can think of is using them for automation in scripts, but that seems pretty niche. Surely the richer UI of IDEs outweighs that?

Nimo 🏳️‍🌈

@nimobeeren.com

25 June 2025

One thing I will add is that I can see the appeal of a more focused/constrained tool for development. My IDE already feels a little overloaded with multiple windows, panels, sidebars and a million keyboard shortcuts. Partly my choice, but a window with a text box might serve me better in some cases.

Alastair McDermott is typing…

@alastairmcdermott.bsky.social

26 June 2025

I love my command line interface. Might be a UNIX thing.

Fran Litterio

@fpl9000.bsky.social

26 June 2025

Gemini CLI can modify its own instructions to remember things. Here, I tell it to remember to run commands on my Windows system using Cygwin Bash instead of cmd.exe.