AGENTS.md Editor

AGENTS.md tells AI coding agents how to work with your project. It's the most important file in your repo that nobody talks about.

What Goes in AGENTS.md

Basically everything an AI needs to know about your project:

• Tech stack and architecture
• Coding conventions
• Things to avoid
• Common commands
• File structure

Different tools call it different things:

• AGENTS.md or CLAUDE.md for Claude Code
• .cursorrules for Cursor
• .github/copilot-instructions.md for Copilot

Same idea. Markdown file with instructions for the AI.

Why I Use markjason for This

I edit my agent instructions constantly. Like, dozens of times a day when tuning a new project.

Three things matter:

Speed. Opens in 0.3 seconds. I'm not waiting for VS Code to load just to add a line.

Token count. ⇧⌘I shows tokens. Every word in AGENTS.md is a word that's not available for actual code context. Keep it tight.

Live sync. Sometimes my agent modifies its own instructions. I see those changes instantly without refreshing.

Quick Tips

Be specific, not verbose.

Bad: "Please always remember to use TypeScript for all code in this project because it provides type safety..."

Good: "Use TypeScript. No exceptions."

Show examples. A code snippet beats a paragraph of explanation.

Update often. Your agent instructions should evolve with your project.