Prompt Routing for Engineers
Prompt routing is a process that guides how tasks or requests are directed to different models or strategies within an LLM system. It ensures that each prompt is handled by the most suitable model or pathway, improving efficiency and safety.
This guide explains the concept of prompt routing, its components, and how it can be implemented using OpenSmartRoute. It covers the routing strategies, policy layers, and decision mechanisms involved in prompt routing.
What is Prompt Routing?
Prompt routing involves directing prompts or user requests to specific models, agents, or strategies based on predefined policies, confidence scores, or contextual information. It is essential for managing multiple models, enforcing security policies, and optimizing performance.
Prompt routing can be simple, such as selecting a model based on language, or complex, involving multiple decision layers and confidence calibration. It helps in reducing costs, improving response quality, and maintaining safety standards.
Components of Prompt Routing
Routing Policies
Routing policies define the rules for directing prompts. These include allow/deny lists, region restrictions, data boundary considerations, and safety checks. Policies run before scoring and are never traded off.
Scoring and Evaluation
After policies are applied, prompts are scored based on utility metrics like quality, cost, and latency. An ensemble of models and strategies can produce a confidence estimate for each prompt.
Decision Layers
The decision layer, often called a routing strategy, evaluates scores and confidence levels to select the best model or to abstain if no safe option exists. Calibration can be used to adjust scores for better accuracy.
Generative Routing
Generative routing employs an LLM as a judge or router, formatted with templates like PROMPT. The LLMJudgeStrategy class allows for flexible routing decisions based on generated scores.
Implementing Prompt Routing with OpenSmartRoute
OpenSmartRoute provides tools to implement prompt routing effectively. The SDK supports strategies, policies, and calibration, enabling engineers to build robust routing pipelines.



