I built this in about 30 minutes of aggregate effort over the course of an evening while yelling at people about zoning reform.

• It renders Markdown. This is a totally solved problem in computer science and I used gonzalezreal/swift-markdown-ui to do it here.

• It keeps a durable history of the Markdown files you've viewed.

• You can associate it with the .md file type so it comes up with you click a Markdown file. So far so good here with the features, right?

• It supports TEXT SEARCH TECHNOLOGY. This is a feature that other Markdown viewers on the App Store don't support. I may patent it.

• It renders a TOC navigator as a sidebar.

• It has color/display themes because I am a frustrated and untalented graphic designer and couldn't resist spending 30 minutes having Claude and GPT 5.5 argue back and forth with me about typography.

• Bookmarks, across all files, the first 5 of which are hotkeyed CMD-[1-5], and a transient in-memory CMD-0 placeholder. Every program must evolve until it manages bookmarks.

• It may do other things I've forgotten about.

Type make.

(Or download a release from Github.)

Install this macOS UI skill I found.

Build me a Markdown viewer, in Swift, as a native macOS app. It should include a sidebar history of all the Markdown files I've viewed. Get it running with xcodebuild and use the computer-use MCP to make sure it's actually working.

Use https://github.com/gonzalezreal/swift-markdown-ui to render Markdown.

Write a PLAN.md and PROGRESS.md for all of this. [ed: I'm not showing them to you, they're embarassing].

Does the markdown render look right to you? [reader: it did not] Evaluate it carefully, scroll it up and down too.

Rebuild, iterate until it's actually using the markdownui stuff.

/macos-design clean up the UI; use computer-use MCP to verify your changes. Make it real nice.

Does history survive restart? It should. I should be able to slide left to reveal a delete button for history items.

Ok I need text search, standard macOS pattern, I only need normal text search nothing fussy.

My big complaint is that it doesn't highlight the token or the line it found the match on, so it's hard to see where it is.

Render a clickable table of content nav based on h1/h2/h3 headers in the markdown, as an additional, collapsible sidebar. use the macos-design skill to make it look good, and test with computer-use.

Can I associate markdown files with this app so when i click them they come up in the viewer?

Then some boring packaging stuff, and also Claude figured out how to make the icon work.

Note: this log is less authentic now since Josh & I fell into a hole of trying to (and succeeding at) building the best conceivable Markdown viewer. But those prompts alone did get us to a Markdown viewer that was better than anything on the app store.

I make it look real nice like.