Cai

About Cai

Cai is a free, open-source AI action layer for macOS that sits between a text selection and whatever you want done with it. Select text or an image anywhere in the system, press Option-C, and a list of actions appears: AI prompts, terminal scripts, URL shortcuts, summaries, translations, OCR, opening a GitHub issue over MCP, filing a Linear ticket. The distinction the project draws is precise and worth repeating — a clipboard manager stores your selection, and a chat app requires you to switch to it and paste; Cai acts on the selection inline, where it already is. Actions are composable rather than one-shot: you can save chains that pipe a selection through an AI prompt, then a script, then a destination such as Slack, a webhook, AppleScript or an Apple Shortcut, all behind a single keystroke. It reads what was selected — a meeting invite, an address, a code block, a screenshot — and surfaces the relevant actions automatically instead of showing a fixed menu. A local model, Ministral 3B running through MLX, ships built in, so there is no API key, account or setup step before first use; Apple Intelligence on macOS 26 and later, LM Studio, Ollama and cloud APIs are all supported as alternatives. MIT licensed, installable through Homebrew.

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