what is lattice-reader fr?

Lattice Reader is a browser tool for reading papers and long documents one piece at a time, instead of getting a summary of the whole thing dumped on you. You select a snippet of text and ask about just that piece, with the rest of the document available as context. There are two explanation modes: Basic, which restates the selected text in plain English using analogies and examples, and Define, which pulls out every technical term or symbol in the selection and explains it in light of the document around it. Each snippet you ask about becomes its own conversation thread that you can keep following up on, and you can also ask a general question without selecting any text first. A toggle lets you switch between Document mode, where the document is sent along as context, and General mode, where you get a plain assistant with no document attached. You can also highlight and annotate passages, invert PDF colors for dark mode reading, choose from several reading themes, and narrow which pages count as context so a long paper with a big appendix does not waste tokens. The tool can hold several documents at once, each in its own separate session. Lattice Reader is bring your own key: you connect your own account with Google Gemini, which has a free tier and needs no credit card, Anthropic Claude, OpenAI, OpenRouter, or a fully local Ollama setup. The whole app is static files with no server, so your key never passes through anyone else's backend, though it is still stored in the browser, which any script on the page could read. To run it yourself you need Node and npm: install dependencies and run the dev script locally, or deploy the built static files to GitHub Pages, Render, Netlify, or Vercel. It is built with JavaScript. The README also documents some internal design choices, like using prompt caching to cut repeat costs on Anthropic and rebuilding two column PDF text into proper reading order, aimed at people who might want to modify the code themselves.