Lum Select — explain any selection

Select text on any page, click ✦ What's this? and the AI answer streams right beside it. Ask follow-up questions in place.

Select a word, a phrase, a piece of code or part of an AI chat reply, and a small toolbar appears above it: ✦ What's this? · Simpler · Example · Deeper · Ask… Click it and a card opens right next to the selection, with the answer streaming in as it is generated. Keep the conversation going: ask a follow-up question right in the card. Click outside the card to close it. What it's for: • reading docs and articles in a foreign language or an unfamiliar field • making sense of commands, configs and logs right on GitHub, Stack Overflow or a wiki • understanding replies from AI chats and coding agents without copy-pasting them into a new window How to use it: • select text with the mouse and the toolbar appears on its own • Shift+Z on a selection gives an answer in your default mode • Alt+Z (⌥Z on Mac) works even where a site captures key presses • right-click → ✦ Lum, including in PDFs (the answer opens in the side panel) • the side panel has a box where you can paste any text Settings: • interface in English or Russian • answer language: same as the interface, same as the selected text, or always English / Russian • default answer mode: What's this?, Simpler, Example or Deeper • works with your own API key for the AI service you choose, any OpenAI-compatible server, or a local model with no key; pick the model from the list available to your key Privacy: • a request is sent only when you trigger it • what is sent: the selected text, part of the surrounding paragraph and the page title; sending the page address can be turned off • keys are stored only in this browser and are never synced • no servers of our own, no analytics, no tracking: requests go straight to the provider you chose You need your own API key or a locally running model.