"promptfoo for golang" - A flexible, embeddable evaluation framework for LLM applications

Evalaf is a comprehensive evaluation framework for testing and monitoring LLM applications, including RAG systems, agents, and general LLM outputs. Built as a reusable Go module, it can be embedded in any Go project or used as a standalone CLI tool.

• Embeddable: Use as a library in your Go projects
• Extensible: Plugin-based architecture for custom evaluators
• Flexible: Evaluate RAG, agents, LLMs, or any system
• Configurable: YAML/JSON configuration with runtime customization
• Parallel: Concurrent evaluation for fast execution
• Multiple Output Formats: JSON, YAML, Markdown, HTML
• LLM-as-Judge: Use LLMs to evaluate LLM outputs (via Genkit integration)
• Production-Ready: Extract and evaluate production traces

go get github.com/antflydb/anteval

package main

import (
    "context"
    "github.com/antflydb/anteval/eval"
)

func main() {
    ctx := context.Background()

    // Create dataset
    dataset := eval.NewJSONDatasetFromExamples("test", []eval.Example{
        {Input: "What is 2+2?", Reference: "4"},
    })

    // Create evaluators
    evaluators := []eval.Evaluator{
        eval.NewExactMatchEvaluator("exact_match"),
    }

    // Define target function (your LLM/RAG/agent)
    target := func(ctx context.Context, example eval.Example) (any, error) {
        // Call your system here
        return "4", nil
    }

    // Run evaluation
    runner := eval.NewRunner(eval.DefaultConfig(), evaluators)
    report, _ := runner.RunWithTarget(ctx, dataset, target)

    // Print results
    report.Print()
}

# Run evaluation with config file
evalaf run --config evalaf.yaml

# List available metrics
evalaf metrics list

# Validate dataset
evalaf datasets validate testdata/datasets/rag_quality.json

• eval/: Core evaluation library (minimal dependencies)

  • Dataset loading and management
  • Evaluator interface and built-in metrics
  • Evaluation runner and reporting
  • Configuration management

• genkit/: Genkit integration for LLM-as-judge

  • LLM-based evaluators (faithfulness, relevance, safety)
  • Support for multiple models (Ollama, OpenAI, Gemini, Claude)
  • Streaming evaluation support

• rag/: RAG-specific evaluators

  • Faithfulness (answer grounded in documents)
  • Relevance (answer addresses query)
  • Citation accuracy
  • Retrieval metrics (NDCG, MRR, Precision@k, Recall@k)

• agent/: Agent-specific evaluators

  • Query classification accuracy
  • Tool selection correctness
  • Reasoning quality

• ui/: UI embedding helpers

  • Result formatting for dashboards
  • Visualization data structures

• cmd/evalaf/: CLI tool

• Exact Match: Output exactly matches reference
• Regex: Output matches regex pattern
• Contains: Output contains substring
• Fuzzy Match: Levenshtein distance-based similarity

• Faithfulness: Answer grounded in retrieved documents (LLM-as-judge)
• Relevance: Answer addresses the query (LLM-as-judge)
• Citation Accuracy: Validates citation references like [doc_id X]
• NDCG@k: Retrieval ranking quality
• MRR: Mean Reciprocal Rank
• Precision@k / Recall@k: Retrieval effectiveness

• Classification Accuracy: Correct query classification
• Tool Selection: Appropriate tool chosen
• Reasoning Quality: Logical and coherent reasoning (LLM-as-judge)

Create a evalaf.yaml configuration file:

version: 1

evaluators:
  # LLM-as-judge evaluators
  faithfulness:
    type: genkit_llm_judge
    model: ollama/mistral
    temperature: 0.0

  relevance:
    type: genkit_llm_judge
    model: ollama/mistral
    temperature: 0.0

  # RAG evaluators
  citation_accuracy:
    type: rag_citation
    pattern: '\[doc_id\s+([^\]]+)\]'

  retrieval_ndcg:
    type: rag_retrieval_metric
    metric: ndcg
    k: 10

  # Simple evaluators
  exact_match:
    type: exact_match

  regex_check:
    type: regex
    pattern: "(?i)expected_pattern"

datasets:
  - name: rag_quality
    path: testdata/datasets/rag_quality.json
    type: json

output:
  format: json
  path: results/report.json
  pretty: true

execution:
  parallel: true
  max_concurrency: 10
  timeout: 5m

Datasets are JSON arrays of examples:

[
  {
    "input": "What is the capital of France?",
    "reference": "Paris",
    "context": [
      "France is a country in Europe",
      "Paris is the capital and largest city of France"
    ],
    "metadata": {
      "domain": "geography",
      "difficulty": "easy"
    }
  }
]

Evaluate Antfly's RAG system quality:

// Evaluate RAG endpoint
ragEndpoint := "http://localhost:3210/api/v1/rag"

target := func(ctx context.Context, example eval.Example) (any, error) {
    return callAntflyRAG(ragEndpoint, example.Input)
}

runner.RunWithTarget(ctx, dataset, target)

Monitor customer-specific prompts:

// Evaluate customer's configuration
customerDataset := loadCustomerDataset(customerID)
customerConfig := loadCustomerConfig(customerID)

runner := eval.NewRunner(customerConfig, evaluators)
report, _ := runner.Run(ctx, customerDataset)

// Embed in searchaf dashboard
dashboardData := ui.FormatForDashboard(report)

# In CI/CD pipeline
evalaf run --config ci_eval.yaml --dataset testdata/regression.json

# Fail if pass rate < 95%
if [ $(jq '.summary.pass_rate < 0.95' results.json) = "true" ]; then
  exit 1
fi

// Compare two prompt variations
reportA, _ := runEvaluation(promptA, dataset)
reportB, _ := runEvaluation(promptB, dataset)

// Compare results
if reportB.Summary.AverageScore > reportA.Summary.AverageScore {
    fmt.Println("Prompt B is better!")
}

See the examples/ directory for complete examples:

• examples/simple/: Basic evaluation example
• examples/antfly/: Antfly RAG and Answer Agent evaluation
• examples/searchaf/: searchaf integration example

evalaf/
├── eval/           # Core library
├── genkit/         # Genkit integration
├── rag/            # RAG evaluators
├── agent/          # Agent evaluators
├── ui/             # UI helpers
├── cmd/evalaf/     # CLI tool
├── examples/       # Usage examples
├── testdata/       # Test datasets
├── work-log/       # Design docs
└── docs/           # Documentation

cd examples/simple
go run main.go

go test ./...

This project uses the module path github.com/antflydb/anteval while living in the evalaf/ directory of the antfly repository. This is a nested Go module.

• Minimal dependencies: stdlib + gopkg.in/yaml.v3

• github.com/firebase/genkit/go/genkit
• github.com/firebase/genkit/go/ai

• github.com/spf13/cobra
• github.com/spf13/viper

• Core evaluation library
• Genkit integration (LLM-as-judge)
• RAG evaluators
• Agent evaluators
• CLI tool
• UI integration helpers
• Production trace extraction
• Web UI for evaluation management
• Continuous evaluation mode
• Multi-turn conversation evaluation

This project is part of the Antfly ecosystem. For contribution guidelines, see the main Antfly repository.

[Your license here]

• Antfly - Distributed key-value store and vector search engine
• Firebase Genkit - AI application framework
• promptfoo - Inspiration for this project

• Issues: GitHub Issues
• Documentation: See docs/ directory
• Design Docs: See work-log/PLAN.md