# Use the simplest thing that works

If you can draw the steps as a fixed flowchart, build a workflow. Reach for an agent only when the steps depend on what it finds.

AI developers · Part 04: Agents · Card 5 of 11 · Last updated 2026-10-13

## Analogy

Don't add Redux to a page with one checkbox. Don't add an agent to "extract invoice, save to DB".

## In an agent

Saying this in an interview signals you've shipped real systems, not just demos.

## Practice

### Flashcards

- **Interview: agent or workflow, which do you default to?** A workflow: cheaper and predictable. Use an agent when the path depends on what is found.

### Interview questions

**Agent vs workflow?**

- A workflow runs steps you designed in advance, in a fixed order.
- An agent lets the model choose the next step in a loop, until the goal is met.
- Workflows are cheaper, faster and easier to test; agents handle open-ended tasks.
- Default to a workflow; use an agent when the path depends on what is found.

## Questions people ask

### How do I know if my task even needs an agent?

Try to draw it as a flowchart. If every step and branch can be drawn in advance, build a workflow, or even a single model call. Reach for an agent only when the steps depend on what it discovers along the way, such as investigating why a deploy failed.

### Why do interviewers like the simplest thing that works answer?

It shows you have shipped real systems. Agents add cost, latency and failure modes, so choosing them by default is a warning sign. Saying you start with the simplest design, and add an agent only where the path is unknown, tells the interviewer you weigh trade-offs instead of following hype.

## Related concepts

- [Agent vs workflow](https://studyvisually.com/learn/tech/ai-developers/agents/agent-vs-workflow)
- [Who decides the next step](https://studyvisually.com/learn/tech/ai-developers/llm-basics/ai-levels)
- [Agent](https://studyvisually.com/learn/tech/ai-developers/agents/agent)
- [The agent loop](https://studyvisually.com/learn/tech/ai-developers/agents/agent-loop)

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