Open a repo and feel lost, and the README is usually the first file to read. It’s less a technical spec than an orientation.
Think about walking into an office building. A good lobby has a directory, a reception desk, and a sign for which floor each company is on; without it, you’re wandering hallways and guessing. A README is the lobby for a repository. Every repository should have one, and it can cover technical setup, but the better frame is orientation: Who’s this for? What’s in here? How do I run it? How do I change it safely?
How it shows up
In a code repo, a README may explain the app, the install steps, the commands, and the deployment flow; in a skills repo, it might explain what skills live there, who owns them, and how updates get reviewed. Most are written in markdown, which is why they’re easy to read in GitHub and easy for agents to parse: the .md file is just structured text with headings, links, and lists. For agent work, a README acts like lightweight project instructions for humans and AI, telling a new person or a fresh session how to start without asking ten setup questions. That’s why a good README isn’t a dumping ground: it answers the first questions a serious reader asks and connects to a knowledge base, acting as the doorway that points to the deeper docs rather than carrying every detail.
Why you care
A repo without a useful README wastes attention, since every new person and every new AI session has to rediscover the same basics. A good README makes the first five minutes of understanding cheap.