Prompts, Workflows, Agents and Skills

Four words get used as if they mean the same thing. They do not, and mixing them up is the fastest way to build the wrong thing. A prompt is one request to a model. A workflow is a fixed sequence of steps, some of which call a model, where you decide the order. An agent is a model given a goal and a set of tools, which decides its own steps and keeps going until it thinks it's done. A skill is a packaged set of instructions, and sometimes files and scripts, that an agent loads when a task calls for it.

The real difference is who holds the plan. In a prompt, you do. In a workflow, you wrote it down ahead of time. In an agent, the model makes it up as it goes. In a skill, you wrote it down once, and the agent reaches for it when it fits.

A Worked Contrast

A fictional bookkeeper, Maya, wants to answer client questions faster. As a prompt, she pastes a client email into a chat and asks for a reply. As a workflow, an automation reads new emails, looks up the client in her sheet, drafts a reply and saves it as a draft. As an agent, she gives the system the goal 'answer the client' plus access to her inbox, sheet and calendar, and it decides what to look up. As a skill, she writes down how she answers late-invoice questions, and the agent loads that guide whenever the topic comes up.

Each is right in some place. The mistake is to jump to the most autonomous one because it sounds modern.

Exercise

• List five tasks from your last week.
• For each, write which of the four fits best and why.
• Circle the one where a fixed workflow would be enough.
• Pass condition: five tasks, each labeled with one of the four and a reason, and one circled.