Your first agent workflow starts as one careful prompt, a few tools, and a developer who knows how it should behave. Then the product grows. Support wants a refund workflow. Sales wants a CRM updater. Ops wants report generation. Engineering adds MCP tools, browser actions, retries, and approvals.
Soon, the “agent” is not one system. It is a pile of copied prompts, hidden rules, one-off tool descriptions, old runbooks, and Slack-thread decisions that nobody can safely reuse.
That is prompt sprawl. It makes your AI product messy. It makes production behavior hard to test, hard to review, and hard to roll back.
An AI agent skill registry gives you a cleaner unit of reuse: a versioned, testable package that says what the agent can do, what tools it may use, what inputs it needs, what evidence proves success, and what must never happen.
This guide shows how to build one without turning your small team into a platform team.
