Hi HN, I'm sushi. I built ParkourNote, a personal knowledge management app that currently focuses on research: finding papers, reading PDFs, asking AI about them, and writing.

A few things it does:

Describe a topic, and an agent creates a project, searches arXiv, and imports relevant papers The PDF reader previews citations on hover, overlays translations on the page, and shows original and translated text side by side The agent sees the page you're reading and your selection; you can also connect Claude or ChatGPT via MCP A block editor with math support that compiles LaTeX / Typst to PDF

Demo (7 min): https://youtu.be/yZs2nQJtgkg

ParkourNote is just me. I built it in about a month: the web app, a Flutter mobile app, and a Chrome extension. It isn't even my full-time job. I work on it for an hour or two in the morning before work, plus evenings and weekends.

Two things surprised me along the way:

- The web app uses BlockNote for Notion-style editing, but I wanted Flutter for mobile. I asked Claude to implement a compatible editor in Flutter. It took about a day, and it works: documents round-trip between web and mobile. - In high school I worked as a video editor for MarginNote. Back then, a single 5-minute video took about a month, from scripting to recording, editing, and animation. For ParkourNote, I made launch videos for the Chinese, English, Japanese, and Korean markets in one weekend, plus a second Chinese version cut for portrait viewing. I didn't open a video editor once. It was all done with Claude Opus 5.5.

PG recently posted something along the lines of: in the AI era, you want to be either very close to the users or very close to the intelligence. That resonated with me, but honestly, building this left me a bit lost. I find it hard to think of a consumer software feature that current AI can't build. So if anyone can build anything, where is the moat? I'm genuinely unsure.

The other side of it is exciting, though. Running ParkourNote alone, I feel less like a solo developer and more like a CEO of a small company: I manage product, engineering, marketing, and operations, and somehow it's all manageable. A one-person company feels genuinely possible now, in a way it didn't a few years ago.

Signup is required since the AI features cost money to run; new accounts get 100 free credits after email verification.

Happy to answer questions about the product, the workflow, or the moat question. I'd genuinely like to hear how others are thinking about it.