Marginal-style PDF deep reading workbench

Annotate dense math/CS textbook PDFs sentence by sentence

Problem

Reading dense technical PDFs, there is no frictionless way to reason word-by-word, sentence-by-sentence, line-by-line while recording thoughts; existing note apps force whole-paragraph excerpts or break reading rhythm.

Solution

A native Mac app where you select a sentence or line in a PDF and immediately write your reasoning; annotations are anchored to the exact location and reviewable as a chain of thought per chapter; local storage, no signup, focused on technical books.

Users

Math/CS students, researchers, self-taught programmers

MVP

PDF rendering; sentence/line selection triggers annotation input; anchored annotations with jump-back; chapter-level review of thought chain; local storage and Markdown export.

Revenue

One-time purchase or subscription via Mac App Store or Lemon Squeezy, with student discount

Why now

LLMs make technical learning denser but deep-reading tools have not changed in a decade; AI-assisted coding lets indie devs ship a native Mac niche app fast