Developer Built Lumi with Claude Code: a Free AI-Powered Spotlight for Mac and Windows

Developer AlbertS15 set out to solve one problem: having to either open Spotlight on Mac to find a file, or dig into a browser to ask an AI. Two apps for one action. They wanted a single hotkey for everything. The result is Lumi, a free, open-source app for macOS and Windows.

How it works

A hotkey (⌥ Ё on Mac, Alt+Ё on Windows) opens the search bar. Type a filename and you get results through the OS's built-in index. Type a question and Lumi offers to ask an AI. The app figures out on its own what you're looking for. If you need the AI after files have already turned up, hit Cmd+Return on Mac or Ctrl+Enter on Windows.

Mac uses the Spotlight index, Windows uses Windows Search. There's no custom indexer, so the disk isn't being hammered.

Supported services

Built-in integrations (via official CLIs, no API keys needed): • Claude via Claude Code • ChatGPT via Codex CLI • Gemini via Gemini CLI

OpenAI-compatible: OpenRouter, OpenAI, DeepSeek, Groq, Mistral. Russian services: YandexGPT, GigaChat. Local models: Ollama, LM Studio (free, no internet required).

The interface is available in Russian, English, German, Spanish, and French.

Free options

OpenRouter. Sign up at openrouter.ai, create an API key. Models with :free are free to use: google/gemma-4-31b-it:free, nvidia/nemotron-3-super-120b-a12b:free.

Ollama. Install it locally, download a model, connect it to Lumi. Everything runs on your own machine.

In Russia, Ollama, GigaChat, and YandexGPT all work.

Technical architecture

Mac: Swift + AppKit + SwiftUI, built with a single swiftc call. Windows: C# + WPF + .NET 8. Electron was avoided — speed and memory efficiency were priorities.

The search window (an NSPanel on Mac) doesn't steal focus. On Windows, the hotkey is handled via scan code 0x29. Responses stream in via JSON (Claude, Codex, Gemini) or Server-Sent Events (OpenAI). Keys are stored in the system keychain (Keychain on Mac, DPAPI on Windows).

Building it with Claude Code

All the code was written by Claude Code, an AI assistant. AlbertS15 explained what was needed in plain language: merge Spotlight and a search bar, support different models, add Windows, add languages. Then they used the builds themselves and decided what to change. Claude wrote the code and set up GitHub Actions.

The key point: real users matter more than anything. The most useful fixes came from friends. For instance, Lumi would say "Claude Code not found" when a friend wanted a different model. On a 403 error, it would say "invalid key," even though requests were actually being blocked by country. AlbertS15 wouldn't have caught that alone.

Plans and links

Question history, asking questions about a screenshot, quick commands ("translate this," "explain this code").

github.com/AlbertS15/Lumi (MIT license), Telegram channel. The app isn't signed with Apple or Microsoft certificates, but the code is fully open — anyone can check it or build it themselves.