kitio.aiAdded Nov 5, 2026
Butterfish
FreeOpen-source shell wrapper that adds AI prompts to bash and zsh
What is Butterfish?
Butterfish is an MIT-licensed command-line tool that adds AI prompting to your normal bash or zsh shell. Starting a line with a capital letter sends it to an OpenAI-compatible model, which can see your recent shell history and answer questions like why a command failed.
You run butterfish shell, keep working as usual, and ask for commands, explanations or general answers inline without copying and pasting. Commands the AI suggests show up as autocomplete, and a goal mode prefixed with an exclamation mark lets it run and debug commands as an agent.
It installs through Homebrew on macOS or with go install, runs on macOS and Linux, and asks for an OpenAI API key on first launch. There is also a Neovim plugin, and the project welcomes outside contributions on GitHub.
Features
- AI prompts inside bash and zsh
- Shell history as context
- Command autocomplete from AI
- Goal mode agent
- Neovim plugin
Tags
Releases
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Organization
Peter Bakkum
Listed by kitio.ai · unverified owner
Pricing
- Pricing model
- Free
- Paid options from
- 100% free
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Pros and cons
Pros
- Free and MIT licensed
- No copy and paste between tools
- Keeps your existing shell setup
Cons
- Needs your own OpenAI-compatible API key
- No Windows support
- Agent mode can run commands on your system
Prompts & results
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Reviews
Q&A
What is Butterfish?
Butterfish is an MIT-licensed command-line tool that adds AI prompting to your normal bash or zsh shell. Starting a line with a capital letter sends it to an OpenAI-compatible model, which can see your recent shell history and answer questions like why a command failed.
Which shells and systems does Butterfish support?
It wraps bash and zsh and runs on macOS and Linux.
Does Butterfish work with models other than OpenAI?
It is built for the OpenAI API and also accepts OpenAI-compatible APIs.
How much does Butterfish cost?
Butterfish is 100% free.
Is there a free version of Butterfish?
Yes. Butterfish is completely free to use.
What are the main features of Butterfish?
AI prompts inside bash and zsh, Shell history as context, Command autocomplete from AI, Goal mode agent, Neovim plugin.
Who makes Butterfish?
Butterfish is made by Peter Bakkum.
What are the best alternatives to Butterfish?
Popular alternatives include mini-SWE-agent, Stakpak, Marmot.