Show HN: Cai – Local AI Action Layer for macOS (Free, MIT, MLX)

+ Press ⌥C to run custom AI prompts and scripts anywhere. Send results to GitHub, Linear or any API. "You did in a very short time what Apple Intelligence failed to deliver." @nemuro87 on r/LocalLLM Cai is a free, open-source AI action layer for macOS. Select any text or image, press ⌥C, and instantly run custom actions: AI prompts, terminal scripts, URL shortcuts, summaries, translations, OCR, GitHub issues via MCP, Linear tickets. Unlike clipboard managers, Cai acts on your selection, not just stores it. Unlike AI chat apps, it works inline without app switching. Ships with a built-in local AI model (Ministral 3B via MLX). No API key, no account, no setup. Also supports Apple Intelligence on macOS 26+, LM Studio, Ollama, and cloud APIs. Local by default. Cloud optional. MIT licensed. Three steps. One shortcut. Zero app switching. Highlight text in any app. An error in terminal, a Slack message, a screenshot, a draft email... Press ⌥C. See your list of actions. No tabs, no distractions. Pick an action, done. Summarize, create a ticket, run a script or route it anywhere. Cai reads what you selected (meetings, addresses, code, images) and surfaces the right actions automatically. Build your own actions with custom prompts, shell scripts, URL searches. Route results anywhere. Your own action library Save any AI prompt, shell script, or URL shortcut as a one-keystroke action. Your library grows with you. $ lsof -ti :{{selected text}} | xargs kill -9 $ gh pr list --search "{{selected text}}" ✦ Translate to a git command: {{selected text}} → "undo last 2 commits" → git reset --soft HEAD~2 Stay in flow. Stay private. Make it yours. Create issues and tickets with AI from any selected text or screenshot. Results appear right where you are. No tabs, no copy-paste loops. Select a screenshot or error image. Cai extracts the text, then runs any action on it. All processing stays on your machine. Want a cloud provider? Your choice. Search, pin, and reuse your last 100 clipboard items. Replace your selection inline, or send results to Slack, Notion, or any app via custom destinations. Use our built-in model, load any model from the HuggingFace MLX community, connect to a local server, or use a cloud provider like OpenRouter. Select some text, let Cai do the rest. Use AI without switching apps. Yes. Cai is free and open source — no subscription, no trial, no account required. If you choose to use a cloud model (like OpenAI or OpenRouter), you'll need their API key, but the app itself is free. Clipboard managers store and organize what you copy; Cai acts on it. And unlike ChatGPT or other AI tools that need you to switch to a separate app, Cai runs directly on your selected text in any app, without breaking your flow. Connect GitHub or Linear, then create issues or tickets without leaving what you're doing. It's a custom-action layer that runs locally on your Mac by default. Detailed comparisons: vs Maccy, vs ChatGPT, vs Raycast, vs Bolt AI, vs Alter. Yes. The built-in models, Apple Intelligence, and local LLM providers all run on-device — everything works without internet. Cloud providers need internet, but that's optional. Yes. By default, Cai runs locally on your Mac and nothing leaves the device. If you connect a cloud model, your selected text is sent only to that provider. The choice is yours. Cai ships with Ministral 3B, Qwen 2.5 7B, Apple Intelligence on macOS 26+, local servers (LM Studio, Ollama) and cloud APIs like OpenRouter. You can also load any MLX model from the HuggingFace MLX community. More info in our docs. You can create custom actions and destinations using AI prompts, URL templates, shell scripts, webhooks, deeplinks, and more. Open Cai's settings → Custom Actions to start. Full guide in the docs. Browse community-shared actions at cai-extensions. Open Cai's settings → Connectors, paste a GitHub personal access token or Linear API key, and test the connection. "Create GitHub Issue" and "Create Linear Ticket" then appear in your action list. Step-by-step guide in the docs. Cai uses the system hotkey ⌥C to copy your selected text via a simulated ⌘C. macOS requires Accessibility access for apps that interact with system-level keyboard commands. This is what lets Cai work in every app, from Safari to Slack to Terminal. To enable it, open System Settings → Privacy & Security → Accessibility and toggle Cai on.