Kognito is a research assistant developed by me for personal documents. You upload PDFs, websites, or notes you’ve written into a notebook and ask questions about them. Each statement in an answer has a footnote. A click on it jumps to the point in the document from which it originated. From a selection of sources, six formats can be generated: briefing, FAQ, timeline, mind map, flashcards, and a narrated audio overview. The most complex part was dealing with large amounts of text. What fits in the prompt goes in completely. What is too large is broken down into passages and searched through embeddings. Each passage remembers its character position in the original; otherwise, the footnotes would point to nowhere. Technologies: Next.js 16, React 19, TypeScript, Tailwind CSS, PostgreSQL, Drizzle ORM, AI SDK, Better Auth, Vitest, and Playwright Infrastructure: Vercel, Neon, Vercel Blob, and AI Gateway.