Butterfish Shell: AI-Powered Command Line Assistant

Butterfish Shell transforms your everyday terminal into an AI-augmented workspace by wrapping bash or zsh with LLM capabilities powered by OpenAI or compatible APIs. Instead of switching between a browser and your terminal to ask an AI for help, you can type natural language prompts directly into your shell session and get instant, context-aware suggestions, explanations, and command completions. Beyond simple autocompletion, Butterfish introduces Goal Mode, a feature that lets an AI agent autonomously execute a sequence of shell commands to accomplish a stated objective, with an 'Unsafe' variant for power users who want fewer guardrails. Combined with customizable prompt templates, this makes Butterfish a flexible tool for engineers who want to speed up repetitive command-line work, troubleshoot failures faster, or offload multi-step automation to an AI agent. Because it integrates at the shell level rather than as a separate chat interface, Butterfish keeps your workflow uninterrupted—you stay inside bash or zsh, and the AI simply becomes another capability of the environment you already use every day.

Install Butterfish using Homebrew (on macOS) or via `go install`. Launch an AI-enabled shell session by running `butterfish shell`. To prompt the AI, simply start a command with a capital letter. For automated task execution, prefix your command with `!` to enter Goal Mode, or `!!` for Unsafe Goal Mode where the agent executes commands with fewer restrictions. Prompt templates can be customized by editing the configuration file at `~/.config/butterfish/prompts.yaml`.