Show HN: I built a native macOS Markdown viewer 100% with AI coding agents

I built Markdown Viewer because every Markdown app I found was either bloated (VS Code, Obsidian) or too bare-bones. Wanted something that loads instantly, renders Obsidian-style features cleanly, and weighs in at a few megabytes.

Built with Tauri 2 (Rust backend + webview frontend): - GitHub Flavored Markdown + Obsidian extensions (wikilinks, callouts, emoji, math, Mermaid diagrams) - Frontmatter rendered as a structured metadata bar above content - HTML sanitization via ammonia for security - No heavy dependencies, no Electron

What makes it interesting isn't so much the features — but how it was built. Every line of Rust, CSS, and JavaScript was written by AI coding agents (pi.dev/Qwen and Claude Code) without a single human writing code. No hand-holding, no "prompt then copy-paste" — just a high-level brief and iterative agent-driven development.

I've been using this project to hone into my pi.dev setup - am getting somewhere with pi.dev/Qwen3.6 with a small set of extensions. Trying to avoid Claude Code/Opus for this project - want to see what I can do with local LLM.

Key stats: - Instant load (no webview overhead, pure rendering) - ~few MB binary - Sanitized HTML via ammonia (XSS-safe) - Open source on GitHub

Open source at https://github.com/rajatarya/mdviewer