:exacto to a model slug, OpenRouter prefers providers with stronger tool-calling quality signals for that model instead of using the default price-weighted ordering.
Using the Exacto variant
Add:exacto to the end of any supported model slug. This is a shortcut for setting the provider sort to Exacto on that model.
What is the Exacto variant?
Exacto is a routing shortcut for quality-first provider ordering. Unlike standard routing, which primarily favors lower-cost providers, Exacto prefers providers with stronger signals for tool-calling reliability and deprioritizes weaker performers.Why use Exacto?
Why we built it
Providers serving the same model can vary meaningfully in tool-use behavior. Exacto gives you an explicit, request-level way to prefer higher-quality providers when you care more about tool-calling reliability than the default price-weighted route.Recommended use cases
Exacto is useful for quality-sensitive, agentic workflows where tool-calling accuracy and reliability matter more than raw cost efficiency.How Exacto works
Exacto uses the same provider-ranking signals as Auto Exacto, but applies them explicitly because you chose the:exacto suffix.
We use three classes of signals:
- Tool-calling success and reliability from real traffic (see How Tool-Calling Success Rate Is Measured for the underlying methodology)
- Provider performance metrics such as throughput and latency
- Benchmark data from OpenRouter’s benchmark harness (see What the Benchmark Harness Runs for the benchmarks and parameters, and Where to Find the Scores for the published results)
Exacto vs. Auto Exacto
- Auto Exacto runs automatically on tool-calling requests and requires no model suffix.
:exactois the explicit shortcut when you want to request the Exacto sorting mode directly on a specific model slug.
Supported models
Exacto is a virtual variant and is not backed by a separate endpoint pool. It can be used anywhere provider sorting is meaningful, especially on models with multiple compatible providers. In practice, Exacto is most useful on models that:- Support tool calling
- Have multiple providers available on OpenRouter
- Show meaningful provider variance in tool-use reliability
If you have feedback on the Exacto variant, please fill out this form:
https://openrouter.notion.site/2932fd57c4dc8097ba74ffb6d27f39d1?pvs=105