Skills and Reusable Instructions
Package your best workflows into skills, commands, and templates that any agent can load on demand.
You've probably written a great prompt at least once: the one that finally got release notes in exactly your team's format, or a code review that catches the things you care about. Then you lost it in a chat history, or pasted slightly different versions into a dozen sessions, each one a little worse than the original.
Your best workflows deserve better than copy-paste. This lesson shows you how to package them as skills, commands, and templates: reusable instruction bundles that agents load exactly when they're needed. You'll learn how skills keep context lean through progressive loading, how to write the one line that decides whether a skill ever gets used, and how to build, test, and share a complete skill. By the end you'll have turned one of your own repeated workflows into something any agent on your team can run.
The problem with putting everything in one file
The obvious place for reusable instructions is your project instruction file (CLAUDE.md, AGENTS.md, or a custom GPT's instructions). That works for a while. Then the file grows to include release procedures, the code review checklist, database migration steps, the brand style guide, and how to write incident reports.
Now every session pays for all of it. The agent fixing a typo carries the whole incident-report procedure in context. As you learned in From Prompt Engineering to Context Engineering, irrelevant instructions aren't free: they cost tokens and dilute attention.
The fix is to separate instructions by when they're needed:
| Kind of instruction | When it applies | Where it belongs |
|---|---|---|
| Always-true facts and rules | Every session | Project instruction file |
| A workflow for a specific kind of task | Only when doing that task | Skill |
| A procedure you trigger by hand | When you decide to run it | Command (or a skill you invoke by name) |
| A fill-in-the-blanks prompt | When you paste it | Template |