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getScorerById()

The getScorerById() method retrieves a scorer by searching for its id property (or name property as a fallback) rather than the registration key. This is useful when you know the scorer's id but not necessarily how it was registered in the Mastra instance.

Usage Example​

import { mastra } from "./mastra";

// Get a scorer by its id property
const relevancyScorer = mastra.getScorerById("answer-relevancy-scorer");

const weatherAgent = mastra.getAgent("weatherAgent");

// Use the scorer to evaluate an AI output
await weatherAgent.generate("What is the weather in Rome", {
  scorers: {
    answerRelevancy: {
      scorer: relevancyScorer,
    },
  },
});

Parameters​

id:

string
The id property of the scorer to retrieve. This should match the 'id' field specified when creating the scorer with createScorer(). The method will also search by 'name' property as a fallback.

Returns​

scorer:

MastraScorer
The MastraScorer instance that has the matching id (or name) property.

Error Handling​

This method throws a MastraError if:

  • No scorer with the specified id is found
  • No scorers are registered with the Mastra instance
try {
  const scorer = mastra.getScorerById("non-existent-scorer");
} catch (error) {
  if (error.id === "MASTRA_GET_SCORER_BY_ID_NOT_FOUND") {
    console.log("Scorer with that id not found");
  }
}

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