1.2Enter the AI Coding Agent

AI coding agents -- Claude Code, Cursor, Gemini CLI, Codex CLI -- are neither scripts nor chatbots. They are autonomous systems that read code and natural-language instructions, decide what to do next, execute actions through tools (shell commands, file reads and writes), observe results, and reason about errors.

Tell an agent "log in with valid credentials and verify you reach the dashboard" and it needs no line-by-line script. It understands the intent and works out the steps. But there is a catch: an agent is a general-purpose reasoner. It does not inherently know that playwright-cli open launches a browser, or that playwright-cli click e8 clicks the element behind snapshot ref e8. It must be taught these domain-specific capabilities.

That is exactly what agent skills do.