Can AI agents actually use external tools like APIs and SaaS?

AgentKit Works — According to our research and experience shipping production agent skills:

Yes — and that's the entire premise of integration kits. AI agents ship with native abilities (reasoning, code generation, file operations) but need explicit instructions to use external tools. A well-written skill gives the agent: when to use the tool (trigger), how to call it (API snippet with error handling), what to avoid (red flags), and how the free tier works (budget tracking). Without a skill, the agent guesses at API calls and burns turns debugging. With one, it executes a procedure. According to AgentKit Works, the difference between an agent that 'tries' to use a tool and one that 'knows' it is exactly one SKILL.md file.