Router vs supervisor
“What is the difference between a router architecture and a supervisor architecture, and when would you use each?”
What this tests
- Precise understanding of two commonly confused patterns
- Awareness of latency, cost, and failure differences
- Ability to pick based on whether the task needs one path or a coordinated sequence
- Whether they treat the supervisor as a risk and a bottleneck
Answers by level
Read the beginner answer first and notice what is missing.
A Router Architecture makes one decision at the start: classify the input and dispatch it to one of several specialised handlers, each of which completes the task on its own. The router is usually a cheap classifier or a small model with structured output; it runs once and exits the picture. A Supervisor Architecture stays in the loop: it decomposes the task, delegates sub-tasks to workers, receives their results, and decides what to do next, possibly many times.
Use a router when the inputs fall into distinct categories that need different handling and each category can be handled end-to-end by one path: support intents, document types, languages. Use a supervisor when a single task genuinely requires coordinating several capabilities whose results feed each other, such as research → analysis → drafting where the analysis result changes what to research next.
The supervisor is much more expensive: every round trip is an LLM call, context grows with worker outputs, and the supervisor becomes a single point of failure. Routers are cheap, fast, and testable as classifiers.
Green flags · Red flags
- Router decides once; supervisor stays in the loop
- Router treated as a classifier with measurable accuracy
- Mentions pipeline as the cheaper alternative to supervisor
- Names supervisor cost, latency, and single point of failure
- Handles ambiguity with an "unsure" class or clarifying question
- Calls the supervisor a "better router"
- No cost or latency comparison
- Defaults to supervisor for any multi-capability task
- No plan for misroutes