Why I Built an Editor for AI Coding

I use Claude Code in the terminal. The AI writes code. I don't need an IDE open anymore. But I still need to read and edit markdown files constantly.

The Problem

My workflow looks like this:

• Claude Code runs in terminal
• I tell it what to build
• It writes the code
• I review diffs in the terminal

No IDE. No VS Code. Just terminal + AI.

But I constantly need to check files:

• AGENTS.md with agent instructions
• CLAUDE.md with project context
• .env with API keys
• mcp.json with tool configs

Opening VS Code for this felt absurd. 3+ seconds to load an IDE just to read a markdown file? Plus 500MB of RAM sitting there?

I don't need syntax highlighting for 47 languages. I need to read three file types.

The Solution

I built markjason. Native macOS app that only does .md, .json, and .env.

Opens in 0.3 seconds. Uses about 100MB RAM. That's it.

Live Sync Changes Everything

The feature I didn't know I needed: live file sync.

I keep AGENTS.md open in markjason while Claude Code works. When the agent updates the file, I see it instantly. No refresh button. No "file changed on disk" dialog. Just live updates.

It's like watching the AI think.

Token Counting

When you're writing prompts, you need to know if they're getting too long. Hit ⇧⌘I and markjason shows you the token count. Simple.

Who This Is For

You might like markjason if you:

• Use Claude Code, Codex, or Aider in terminal
• Don't keep an IDE open all day
• Find yourself opening VS Code just to check one file
• Want something faster than TextEdit but simpler than an IDE

Who This Is NOT For

If you already have VS Code or Cursor open all day, you don't need this. Your IDE can handle markdown just fine. markjason is for people who've moved past the IDE.

Try It

Free download. No account. No tracking.

Set it as default for .md, .json, and .env files. Double-click opens instantly.