// GLOSSARY -- AGENTIC AI

What is Semantic Routing?

1 min read Updated

Semantic routing is the technique of directing requests, queries, or tasks to the appropriate handler (agent, tool, or model) based on the semantic meaning of the input rather than exact keyword matching or fixed rules.

WHY IT MATTERS

Traditional routing uses rules: if the URL starts with /payments, go to the payment service. Semantic routing uses meaning: if the user's intent is about payments, route to the payment agent — regardless of how they phrased it.

This is typically implemented using embeddings. Requests are converted to vectors, compared against reference vectors for each possible route, and directed to the closest match. It's fast (vector comparison is sub-millisecond) and flexible (handles paraphrasing, different languages, and novel phrasings).

In agent systems, semantic routing determines which specialized agent handles a request, which model to use for a given query, or which tool is most appropriate for a task. It's a key component of multi-agent orchestration.

FREQUENTLY ASKED QUESTIONS

How is semantic routing different from intent classification?
They're closely related. Intent classification assigns a request to a predefined category. Semantic routing uses the classification to direct the request to a handler. In practice, the terms are often used interchangeably.
What are the limitations of semantic routing?
Ambiguous inputs can be misrouted. Edge cases near category boundaries are unreliable. And adversarial inputs can deliberately trigger wrong routes. Always have fallback handling for uncertain classifications.
Do I need embeddings for semantic routing?
Not necessarily. You can use LLM-based classification (ask the model which route to take), but this is slower and more expensive. Embedding-based routing is preferred for high-throughput, low-latency scenarios.

FURTHER READING

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