# Mixture of Experts Routing

> Route each request to one or more domain-expert agents, where each expert holds deep capability in a narrow area.

- **Category**: Agentic AI
- **Subcategory**: Routing & Composition
- **Canonical URL**: https://designpattern.fyi/patterns/mixture_of_experts_routing/

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## Description
**Intent**: Route each request to one or more domain-expert agents, where each expert holds deep capability in a narrow area.
**Context**: A team is building one agent that serves users across several substantially different professional domains — for example legal questions, medical questions, financial planning, and technical support. Each of these domains has its own vocabulary, its own authoritative sources, and its own conventions for what a good answer looks like. A single shared prompt cannot credibly carry deep expertise in all of them at once because the prompt budget and the model's attention are finite.
**Solution**: Define experts (specialised system prompts, tool palettes, possibly fine-tuned models). A router classifies queries by domain. Route to one expert (top-1) or to multiple experts whose outputs are aggregated. Distinct from standard routing by emphasising deep specialisation per expert.


## Use Cases
- Users in specialist domains feel under-served by a generalist agent.
- Domain experts can be defined with their own prompts, tools, or fine-tuned models.
- A router can classify queries by domain reliably enough to dispatch.





## Trade-offs


### Advantages

- Depth per domain.

- Independent expert evolution.




### Considerations & Drawbacks

- Domain count grows expert maintenance linearly.

- Cross-domain queries fall through cracks.







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**Reference**: [Original Source](https://www.agentpatternscatalog.org/patterns/mixture-of-experts-routing/)