Langevals Evaluator
The Langevals Evaluator is a comprehensive evaluation component that applies custom rules and criteria to assess language model outputs. It provides flexible evaluation capabilities through configurable rule sets and evaluation fields.

Langevals Evaluator interface and configuration
Usage Note: Configure evaluation rules carefully to match your specific use case. The evaluator's effectiveness depends on well-defined rules and appropriate field selections.
Component Inputs
- Output Text: The text to be evaluated
Example: "Text content for evaluation"
- Field To Evaluate: Specific field or aspect to evaluate
Example: "content", "style", "tone"
- Rule Type: Type of evaluation rule to apply
Example: "length", "complexity", "relevance"
- Rule Value: Specific value or threshold for the rule
Example: "minimum_length: 100", "max_complexity: 0.8"
Component Outputs
- Evaluation Result: Result of the rule evaluation
Example: true/false or score (0-1)
- Details: Detailed evaluation information
Specific metrics and measurements
- Recommendations: Suggested improvements
Actions to improve evaluation results
How It Works
The Langevals Evaluator processes text through configurable rule sets and evaluation criteria, providing detailed analysis and recommendations based on specified requirements.
Evaluation Process
- Rule configuration
- Field selection
- Content analysis
- Rule application
- Result compilation
- Recommendation generation
Use Cases
- Content Evaluation: Assess content quality and relevance
- Style Analysis: Evaluate writing style and tone
- Compliance Checking: Verify content meets requirements
- Quality Control: Maintain content standards
- Performance Monitoring: Track content quality metrics
Implementation Example
const langevalsEvaluator = new LangevalsEvaluator({
outputText: "Content to evaluate...",
fieldToEvaluate: "content",
ruleType: "complexity",
ruleValue: {
maxComplexity: 0.8,
minLength: 100
}
});
const result = await langevalsEvaluator.evaluate();
// Output:
// {
// result: true,
// details: {
// complexity: 0.6,
// length: 150,
// metrics: { ... }
// },
// recommendations: ["Content meets all criteria"]
// }
Additional Resources
Best Practices
- Define clear evaluation rules
- Choose appropriate fields
- Set realistic thresholds
- Monitor evaluation results
- Refine rules based on feedback