
(Open Source) I built a second brain app where AI agents help you think — but you review every change before it happens
Most second brain apps stop at storage. You capture a note, tag it, link it, and hope you find it again someday. NeverWrite is built around the idea that your second brain should actually help you think, not just hold your thoughts. It's a local-first desktop app for macOS and Windows where your notes are plain Markdown files on your machine. No cloud sync, no account required, no telemetry. Your vault is yours.
The part I'm most excited about is the AI layer. NeverWrite supports agents powered by Claude, Codex, Gemini and Kilo, that work directly inside your vault. You can ask an agent to help you synthesize notes on a topic, find connections you missed, or draft a new note from your existing material. The key thing is that agents propose edits and you review them before anything changes, it has inline review hunks like modern code editors. The AI helps you process and connect your knowledge; it never rewrites your vault behind your back. That felt like the only honest way to build this.
If you've been frustrated by second brain tools that are great at capture but useless at synthesis, or by AI tools that feel like a black box you can't trust, NeverWrite is trying to solve both at once. Happy to answer any questions about how the agent review flow works or anything else.
Also, is open source ;)
https://github.com/jsgrrchg/NeverWrite
Have fun with your vaults!