Workflow automation is usually deterministic: when this happens, do that. An AI agent can make flexible decisions about what to do next based on instructions, context, and tool results.
In practice
Automation is best for repeatable processes with clear rules. Agents are useful when inputs are messy, language-heavy, or require judgment before choosing the next step.
What to watch
Agents should not replace simple automation when rules are stable. A predictable workflow is often cheaper, faster, and easier to audit.