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')
  }
}

Related

• getScorer(): Get a scorer by its registration key
• listScorers(): Get all registered scorers
• createScorer(): Learn how to create scorers with ids