Model Routing Is the Hidden System Behind Reliable AI Applications

Most AI applications are not powered by a single model handling every request the same way.

Behind the interface, routing logic determines which model, tool, workflow, or fallback should handle each task.

In Episode 13 of System Prompt, Val and Peter examine model routing and why it has such a major impact on the reliability, cost, consistency, and security of AI systems.

The conversation covers deterministic routing, regular expressions, model selection, tracing, silent reroutes, fallback behavior, and the incremental improvements that turn a basic AI workflow into a dependable product.

WHAT WE DISCUSS

• What model routing is

• Why AI applications use multiple routes

• Different types of routing systems

• Deterministic routing compared with model-based routing

• Using regular expressions and rules to classify requests

• Routing work to different mod