Cai

Select any text or image. Get smart actions.

A privacy-first clipboard assistant powered by local AI.
Your data never leaves your machine.

Website · Download · Extensions

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Cai is a native macOS menu bar app that detects what's on your clipboard and offers smart, context-aware actions. Copy a meeting invite and it creates a calendar event. Copy an address and it opens Maps. Copy a screenshot and it extracts the text. Copy any text and ask your local AI to summarize, translate, or do anything you want — all without leaving your keyboard.

No cloud. No telemetry. No accounts.

How It Works

1. Select text or copy an image anywhere on your Mac
2. Press ⌥C (Option+C)
3. Cai detects the content type and shows relevant actions
4. Pick an action with arrow keys or ⌘1–9
5. Result is auto-copied to your clipboard — just ⌘V to paste

Examples:

• Select "serendipity" → Define, Explain, Translate, Search
• Select "Let's meet Tuesday at 3pm at Starbucks" → Create calendar event, Open in Maps
• Select an email in Mail → Reply, Summarize, Translate
• Select any text → Ask AI: "Extract ingredients for 2 people"
• Copy a screenshot → Image to Text (OCR), then Summarize, Translate, or any action
• Select a project name → Custom action: search in Google Drive (https://drive.google.com/drive/search?q=%s)

Features

• Smart detection of content types (word, text, image, meeting, address, URL, JSON) with context-aware actions
• Image to Text — copy a screenshot or image and Cai extracts the text via on-device OCR (Apple Vision), then run any action on it
• Built-in AI — ships with Ministral 3B, downloaded on first launch. Also compatible with Apple Intelligence (macOS 26+), LM Studio, Ollama, or any OpenAI-compatible server
• Built-in chat — ask follow-up questions with Tab, or press ⌘N to start a new chat without clipboard content
• Ask AI (⌘1) — free-form prompt to do anything: improve writing, create email replies, translate, count words
• Custom actions — save reusable prompts and URL templates, access them by typing to filter
• Output destinations — send results to Mail, Notes, Reminders, or custom webhooks, URL schemes, AppleScript, and shell commands
• Clipboard history — search, pin, and reuse your last 100 clipboard items with ⌘0
• App-aware — Cai knows which app you're in (Mail, Slack, Safari…) and adapts AI responses to match the context
• About You — set personal context (profession, tone, preferences) so AI responses are tailored to you
• Type-to-filter — start typing to filter actions and destinations by name
• Keyboard-first — navigate and execute everything without touching the mouse
• Privacy-first — no internet required, no data leaves your machine

Keyboard Shortcuts

Shortcut	Action
⌥C	Trigger Cai (global hotkey)
↑ ↓	Navigate actions
↵	Execute selected action
⌘1–9	Jump to action by number
⌘0	Open clipboard history (searchable, with pinning)
⌘N	New chat (ask anything, without clipboard content)
⌘↵	Submit custom prompt / Copy result
Tab	Ask a follow-up question on the result
A–Z	Type to filter actions
Esc	Clear filter / Back / Dismiss

Installation

Download

1. Download the .dmg from the latest release
2. Open the DMG and drag Cai.app to your Applications folder
3. Open the app and grant Accessibility permission (see below)
4. Cai will download a small AI model (~2 GB) on first launch — or skip if you already use LM Studio / Ollama

First Launch Setup

On first launch, Cai needs Accessibility permission to use the global hotkey (⌥C) and simulate ⌘C to copy your selection.

Step 1 — Open Cai. It will ask for Accessibility permission. Click Open System Settings.

Step 2 — Toggle Cai on in the Accessibility list.

You're all set! Press ⌥C with any text selected to start using Cai.

Build from Source

git clone https://github.com/clipboard-ai/cai.git
cd cai/Cai
open Cai.xcodeproj

In Xcode:

1. Select the Cai scheme and My Mac as destination
2. Product → Run (⌘R)

Note: The app requires Accessibility permission and runs without App Sandbox (required for global hotkey and CGEvent posting).

LLM Setup

Built-in (zero config)

Cai ships with a bundled AI engine (llama.cpp). On first launch it downloads Ministral 3B (~2 GB) and runs everything locally — no external server needed.

Models are stored in ~/Library/Application Support/Cai/models/. The engine starts automatically on launch and stops when you quit Cai.

Custom models: Drop any .gguf file into the models folder and select it from the model picker in Settings or the action window footer. Cai will restart the engine with your chosen model.

Apple Intelligence

On Macs with an M1 chip or later running macOS 26+, Cai can use Apple Intelligence as a built-in model provider — no download needed. If available, Cai will offer it during first launch setup.

External providers

Cai works with LM Studio, Ollama, or any OpenAI-compatible endpoint (local or cloud). Auto-detects running providers on launch.

AI is optional — system actions (Maps, Calendar, Search, Pretty Print JSON) work without it. API keys are stored in the macOS Keychain.

Custom Actions

Save frequently used prompts and URL templates as custom actions. They appear when you type to filter the action list.

• Prompt — sends clipboard text + your prompt to the LLM (e.g., "Rewrite as email reply")
• URL — opens a URL with clipboard text substituted via %s (e.g., https://reddit.com/search/?q=%s)

Create them in Preferences → Custom Actions.

Output Destinations

Send results to an output destination instead of just copying to clipboard.

Built-in: Email (Mail.app), Save to Notes, Create Reminder.

Custom destinations: Webhook, AppleScript, Deeplink, Shell Command — use {{result}} as a placeholder for your text.

Create them in Preferences → Output Destinations. Enable "Show in action list" for direct-access workflows.

Community Extensions

Browse and install extensions from the cai-extensions repo.

Install: Copy an extension's YAML → press ⌥C → "Install Extension" → review and confirm.

Cai shows a trust confirmation before installing — you'll see the extension name, type, author, and where it sends data (if applicable). AppleScript and shell extensions are blocked from clipboard install for security.

Create your own: Fork the repo, add a YAML file, and open a PR. See the extension guide for details.

Requirements

• macOS 13.0 (Ventura) or later
• Apple Silicon (M1 or later) for the built-in AI engine
• ~2.5 GB disk space for the bundled model (downloaded on first launch)
• Accessibility permission (for global hotkey ⌥C)

Troubleshooting

macOS blocks Cai from opening (building from source) Remove the quarantine flag: xattr -cr /Applications/Cai.app

Global shortcut ⌥C doesn't work

• Check System Settings → Privacy & Security → Accessibility — make sure Cai is listed and enabled
• If still not working, remove Cai from the list and re-add it
• Make sure no other app is using ⌥C (e.g., Raycast, Alfred)

LLM not connecting

• Verify your server is running: curl http://127.0.0.1:1234/v1/models
• Ollama uses port 11434, LM Studio uses 1234 — make sure you selected the right provider

Tech Stack

• SwiftUI + AppKit (native macOS, no Electron)
• Bundled llama.cpp for local LLM inference (ARM64 macOS, Metal GPU)
• Actor-based services for thread-safe async/await
• HotKey (SPM) for global keyboard shortcut

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Built as a side project with Claude Code's help

License

MIT