ExamplesEvalsCompleteness

Completeness Evaluation

This example demonstrates how to use Mastra’s Completeness metric to evaluate how thoroughly responses cover key elements from the input.

Overview

The example shows how to:

  1. Configure the Completeness metric
  2. Evaluate responses for element coverage
  3. Analyze coverage scores
  4. Handle different coverage scenarios

Setup

Dependencies

Import the necessary dependencies:

src/index.ts
import { CompletenessMetric } from '@mastra/evals/nlp';

Metric Configuration

Set up the Completeness metric:

src/index.ts
const metric = new CompletenessMetric();

Example Usage

Complete Coverage Example

Evaluate a response that covers all elements:

src/index.ts
const text1 = 'The primary colors are red, blue, and yellow.';
const reference1 = 'The primary colors are red, blue, and yellow.';
 
console.log('Example 1 - Complete Coverage:');
console.log('Text:', text1);
console.log('Reference:', reference1);
 
const result1 = await metric.measure(reference1, text1);
console.log('Metric Result:', {
  score: result1.score,
  info: {
    missingElements: result1.info.missingElements,
    elementCounts: result1.info.elementCounts,
  },
});
// Example Output:
// Metric Result: { score: 1, info: { missingElements: [], elementCounts: { input: 8, output: 8 } } }

Partial Coverage Example

Evaluate a response that covers some elements:

src/index.ts
const text2 = 'The primary colors are red and blue.';
const reference2 = 'The primary colors are red, blue, and yellow.';
 
console.log('Example 2 - Partial Coverage:');
console.log('Text:', text2);
console.log('Reference:', reference2);
 
const result2 = await metric.measure(reference2, text2);
console.log('Metric Result:', {
  score: result2.score,
  info: {
    missingElements: result2.info.missingElements,
    elementCounts: result2.info.elementCounts,
  },
});
// Example Output:
// Metric Result: { score: 0.875, info: { missingElements: ['yellow'], elementCounts: { input: 8, output: 7 } } }

Minimal Coverage Example

Evaluate a response that covers very few elements:

src/index.ts
const text3 = 'The seasons include summer.';
const reference3 = 'The four seasons are spring, summer, fall, and winter.';
 
console.log('Example 3 - Minimal Coverage:');
console.log('Text:', text3);
console.log('Reference:', reference3);
 
const result3 = await metric.measure(reference3, text3);
console.log('Metric Result:', {
  score: result3.score,
  info: {
    missingElements: result3.info.missingElements,
    elementCounts: result3.info.elementCounts,
  },
});
// Example Output:
// Metric Result: {
//   score: 0.3333333333333333,
//   info: {
//     missingElements: [ 'four', 'spring', 'winter', 'be', 'fall', 'and' ],
//     elementCounts: { input: 9, output: 4 }
//   }
// }

Understanding the Results

The metric provides:

  1. A score between 0 and 1:

    • 1.0: Complete coverage - contains all input elements
    • 0.7-0.9: High coverage - includes most key elements
    • 0.4-0.6: Partial coverage - contains some key elements
    • 0.1-0.3: Low coverage - missing most key elements
    • 0.0: No coverage - output lacks all input elements

  2. Detailed analysis of:

    • List of input elements found
    • List of output elements matched
    • Missing elements from input
    • Element count comparison




View Example on GitHub
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