Exacto Variant

Exacto is a virtual model variant that explicitly applies quality-first provider sorting. When you add :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.

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import { OpenRouter } from '@openrouter/sdk';
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const openRouter = new OpenRouter({
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  apiKey: process.env.OPENROUTER_API_KEY,
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});
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const completion = await openRouter.chat.send({
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  model: "moonshotai/kimi-k2-0905:exacto",
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  messages: [
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    {
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      role: "user",
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      content: "Draft a concise changelog entry for the Exacto launch.",
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    },
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  ],
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  stream: false,
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});
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console.log(completion.choices[0].message.content);

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 and evaluation data as it becomes available

Providers with strong track records are moved toward the front of the list. Providers with limited data are kept behind well-established performers, and providers with poor quality signals are deprioritized further.

Exacto vs. Auto Exacto

• Auto Exacto runs automatically on tool-calling requests and requires no model suffix.
• :exacto is the explicit shortcut when you want to request the Exacto sorting mode directly on a specific model slug.

If you explicitly sort by price, throughput, or latency, that explicit sort still takes precedence.

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