Tero is a native macOS assistant that lives behind one shortcut. It reads what you've selected, suggests the actions that fit, and runs them in place: correct a sentence, reply to a message, turn a date into a calendar event, rename a file or save a video. It's free, works without an account, and uses your own AI provider, or a model running on your Mac.
Features
| |
|---|
| Writing | Correct, Rewrite (natural, professional, casual), Adjust tone, Simplify, Improve prompt, Translate (12 languages), Clean formatting, Change case |
| Reading | Explain, Key points, Extract tasks, Check a claim (with sources), Ask anything (with web answers) |
| Replies | Three suggested intents for the message you selected, then a draft in its language |
| Planning | Create Reminders or Calendar events from a message, always reviewed before saving |
| Numbers & places | Calculate, convert units, currencies and time zones, open in Maps or get directions |
| Files | Rename and batch rename with AI suggestions, move to a folder, summarize images, PDFs and Office documents |
| Videos | Download a YouTube link as MP4 or MP3 into the folder you choose (uses your installed yt-dlp) |
| Clipboard | Local, searchable clipboard history with pins, files, images and links |
| Your own actions | Describe a habit in plain words and Tero turns it into a reusable action |
Everything is keyboard first: arrows to choose, Return to run, Esc to step back. Every action can have its own global shortcut.
Bring your own AI
Tero doesn't resell AI. Add a key in Settings → AI and requests go straight from your Mac to the provider you chose. Your key is stored in the macOS Keychain and never reaches Tero's servers.
| Provider | Protocol | Web answers & claim checks |
|---|
| OpenAI | Responses API | ✓ |
| Anthropic (Claude) | Messages API | ✓ |
| OpenRouter | OpenAI-compatible | ✓ |
| Grok (xAI), Google Gemini, Mistral, Groq, DeepSeek | OpenAI-compatible | — |
| Ollama, LM Studio | Local, OpenAI-compatible | — |
| Any OpenAI-compatible endpoint | OpenAI-compatible | — |
Optionally add a Typesafe key in Settings → AI → Recommendations: Jev then orders the suggested actions, called straight from your Mac like your AI provider. Without it, Tero uses local rules.
Prefer not to manage keys? Tero Pro is an optional subscription with AI included, available from the website.
Install
Download the latest notarized build from Releases, drag Tero to Applications, then grant Accessibility access when asked so Tero can read your selection. Tero updates itself with Sparkle.
To download videos, install the tools once:
brew install yt-dlp ffmpeg
Build from source
Requirements: macOS 14 or later, Xcode 26 or later with Swift 6, Node.js 24 (for the gateway tests).
git clone https://github.com/aymenn8/tero.git
cd tero
open Tero.xcodeproj # scheme "Tero Dev"
The project is set up for the maintainer's Apple team. To run it yourself, select the Tero target → Signing & Capabilities, choose your own team, and change the bundle identifier if Xcode asks. The Tero Dev scheme builds a separate development app with its own settings and Keychain items.
From the command line:
xcodebuild -project Tero.xcodeproj -scheme 'Tero Dev' -destination 'platform=macOS' build
Tests
swift test # core logic (Swift Testing + XCTest)
make check # account and ranking gateway checks (Node)
python3 Scripts/test-byok.py # bring-your-own-key engine against a synthetic provider
UI fixtures such as Scripts/test-panel-layout.py briefly open real panels on your Mac and use synthetic data only.
How it works
Selection (Accessibility, Finder) ──► Recommendations ──► Action bubbles ──► Action
│ │
local rules, optional own AI key ──► provider
Jev ranking (Pro or your own Typesafe key) Tero Pro ──► Supabase gateway
| Path | What lives there |
|---|
Sources/Core | Pure, testable logic (the TeroCore Swift package): action catalogue, recommendations, parsers, file workflows |
Sources/Panel | The floating panel controller and keyboard routing |
Sources/Selection | Accessibility capture and revalidation of the selected text, range and app |
Sources/AI | LocalGateway and AIProviderClient for your own key, and the Tero Pro gateway client |
Sources/UI, Sources/Settings | SwiftUI views, the shared action bubbles and Settings |
Sources/Clipboard, Sources/Habits, Sources/Planning | Clipboard history, personal actions, Reminders and Calendar |
Resources/AI/Prompts.json | The prompts used for every AI action |
supabase/functions | Tero Pro backend: tero-correct, tero-rank, tero-shop, tero-account, tero-events |
supabase/migrations | Database schema for accounts, usage, prompts and the action catalogue |
The app ships pointing to the hosted Tero backend, which only serves Tero Pro accounts. With your own key, Tero works fully without it.
Privacy
- Clipboard history and your personal actions stay on your Mac (personal actions sync only if you sign in).
- With your own key, the content an action needs is sent only to your provider. With a local model, nothing leaves your Mac.
- Tero never logs selected text, prompts or clipboard content.
More in the privacy policy.
Contributing
Issues and pull requests are welcome. Please read CONTRIBUTING.md first, and report security issues privately as described in SECURITY.md.
License
Tero is released under the MIT License. Bundled third-party components keep their own licenses: Sparkle (Resources/Sparkle-LICENSE.txt), Inter (Assets/Fonts/Inter-OFL.txt), Lobe Icons (Resources/LobeIcons-LICENSE.txt) and Beautiful UI (Notices/BeautifulUI.txt).
