# State machine, agent or multi-agent? (cheat sheet)

> Pick the simplest architecture that fits.

Source: https://conversationalaidesign.com/cheatsheets/architecture-chooser.html. Author: Nelson Abacherli Kawakami. Reviewed October 27, 2026.

## Compare
|  | State machine | Single agent | Multi-agent |
|---|---|---|---|
| Control | Highest | Medium | Lowest |
| Flexibility | Low | High | Highest |
| Cost and latency | Lowest | Medium | Highest |
| Testability | Easiest | Moderate | Hardest |
| Best for | Regulated, defined steps | Open tasks with tools | Distinct permissions or parallel work |

## Decide in order
- 1. Defined process and high stakes? State machine
- 2. Unknown steps, few tools? Single agent with limits
- 3. Different permissions, domains or parallel work? Multi-agent
- 4. Only questions about content? Plain RAG

## Hybrid default
- Code owns the what: states, guards, confirmations
- The model owns the language: extraction and phrasing
- Router with confidence thresholds: clarify, RAG, flow, agent, human
- Budgets for steps, tokens and cost

Related modules: Orchestration: state machines, agents and multi-agent systems (https://conversationalaidesign.com/modules/09-orchestration.html)