Claude Agent Skill · by Wshobson

Llm Evaluation

You know those moments when you deploy an LLM change and wonder if you just made things better or worse? This helps you actually measure that with real numbers.

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Terminal · npx
$npx skills add https://github.com/wshobson/agents --skill llm-evaluation
Works with Paperclip

How Llm Evaluation fits into a Paperclip company.

Llm Evaluation drops into any Paperclip agent that handles this kind of work. Assign it to a specialist inside a pre-configured PaperclipOrg company and the skill becomes available on every heartbeat — no prompt engineering, no tool wiring.

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---name: llm-evaluationdescription: Implement comprehensive evaluation strategies for LLM applications using automated metrics, human feedback, and benchmarking. Use when testing LLM performance, measuring AI application quality, or establishing evaluation frameworks.--- # LLM Evaluation Master comprehensive evaluation strategies for LLM applications, from automated metrics to human evaluation and A/B testing. ## When to Use This Skill - Measuring LLM application performance systematically- Comparing different models or prompts- Detecting performance regressions before deployment- Validating improvements from prompt changes- Building confidence in production systems- Establishing baselines and tracking progress over time- Debugging unexpected model behavior ## Core Evaluation Types ### 1. Automated Metrics Fast, repeatable, scalable evaluation using computed scores. **Text Generation:** - **BLEU**: N-gram overlap (translation)- **ROUGE**: Recall-oriented (summarization)- **METEOR**: Semantic similarity- **BERTScore**: Embedding-based similarity- **Perplexity**: Language model confidence **Classification:** - **Accuracy**: Percentage correct- **Precision/Recall/F1**: Class-specific performance- **Confusion Matrix**: Error patterns- **AUC-ROC**: Ranking quality **Retrieval (RAG):** - **MRR**: Mean Reciprocal Rank- **NDCG**: Normalized Discounted Cumulative Gain- **Precision@K**: Relevant in top K- **Recall@K**: Coverage in top K ### 2. Human Evaluation Manual assessment for quality aspects difficult to automate. **Dimensions:** - **Accuracy**: Factual correctness- **Coherence**: Logical flow- **Relevance**: Answers the question- **Fluency**: Natural language quality- **Safety**: No harmful content- **Helpfulness**: Useful to the user ### 3. LLM-as-Judge Use stronger LLMs to evaluate weaker model outputs. **Approaches:** - **Pointwise**: Score individual responses- **Pairwise**: Compare two responses- **Reference-based**: Compare to gold standard- **Reference-free**: Judge without ground truth ## Quick Start ```pythonfrom dataclasses import dataclassfrom typing import Callableimport numpy as np @dataclassclass Metric:    name: str    fn: Callable     @staticmethod    def accuracy():        return Metric("accuracy", calculate_accuracy)     @staticmethod    def bleu():        return Metric("bleu", calculate_bleu)     @staticmethod    def bertscore():        return Metric("bertscore", calculate_bertscore)     @staticmethod    def custom(name: str, fn: Callable):        return Metric(name, fn) class EvaluationSuite:    def __init__(self, metrics: list[Metric]):        self.metrics = metrics     async def evaluate(self, model, test_cases: list[dict]) -> dict:        results = {m.name: [] for m in self.metrics}         for test in test_cases:            prediction = await model.predict(test["input"])             for metric in self.metrics:                score = metric.fn(                    prediction=prediction,                    reference=test.get("expected"),                    context=test.get("context")                )                results[metric.name].append(score)         return {            "metrics": {k: np.mean(v) for k, v in results.items()},            "raw_scores": results        } # Usagesuite = EvaluationSuite([    Metric.accuracy(),    Metric.bleu(),    Metric.bertscore(),    Metric.custom("groundedness", check_groundedness)]) test_cases = [    {        "input": "What is the capital of France?",        "expected": "Paris",        "context": "France is a country in Europe. Paris is its capital."    },] results = await suite.evaluate(model=your_model, test_cases=test_cases)``` ## Automated Metrics Implementation ### BLEU Score ```pythonfrom nltk.translate.bleu_score import sentence_bleu, SmoothingFunction def calculate_bleu(reference: str, hypothesis: str, **kwargs) -> float:    """Calculate BLEU score between reference and hypothesis."""    smoothie = SmoothingFunction().method4     return sentence_bleu(        [reference.split()],        hypothesis.split(),        smoothing_function=smoothie    )``` ### ROUGE Score ```pythonfrom rouge_score import rouge_scorer def calculate_rouge(reference: str, hypothesis: str, **kwargs) -> dict:    """Calculate ROUGE scores."""    scorer = rouge_scorer.RougeScorer(        ['rouge1', 'rouge2', 'rougeL'],        use_stemmer=True    )    scores = scorer.score(reference, hypothesis)     return {        'rouge1': scores['rouge1'].fmeasure,        'rouge2': scores['rouge2'].fmeasure,        'rougeL': scores['rougeL'].fmeasure    }``` ### BERTScore ```pythonfrom bert_score import score def calculate_bertscore(    references: list[str],    hypotheses: list[str],    **kwargs) -> dict:    """Calculate BERTScore using pre-trained model."""    P, R, F1 = score(        hypotheses,        references,        lang='en',        model_type='microsoft/deberta-xlarge-mnli'    )     return {        'precision': P.mean().item(),        'recall': R.mean().item(),        'f1': F1.mean().item()    }``` ### Custom Metrics ```pythondef calculate_groundedness(response: str, context: str, **kwargs) -> float:    """Check if response is grounded in provided context."""    from transformers import pipeline     nli = pipeline(        "text-classification",        model="microsoft/deberta-large-mnli"    )     result = nli(f"{context} [SEP] {response}")[0]     # Return confidence that response is entailed by context    return result['score'] if result['label'] == 'ENTAILMENT' else 0.0 def calculate_toxicity(text: str, **kwargs) -> float:    """Measure toxicity in generated text."""    from detoxify import Detoxify     results = Detoxify('original').predict(text)    return max(results.values())  # Return highest toxicity score def calculate_factuality(claim: str, sources: list[str], **kwargs) -> float:    """Verify factual claims against sources."""    from transformers import pipeline     nli = pipeline("text-classification", model="facebook/bart-large-mnli")     scores = []    for source in sources:        result = nli(f"{source}</s></s>{claim}")[0]        if result['label'] == 'entailment':            scores.append(result['score'])     return max(scores) if scores else 0.0``` ## LLM-as-Judge Patterns ### Single Output Evaluation ```pythonfrom anthropic import Anthropicfrom pydantic import BaseModel, Fieldimport json class QualityRating(BaseModel):    accuracy: int = Field(ge=1, le=10, description="Factual correctness")    helpfulness: int = Field(ge=1, le=10, description="Answers the question")    clarity: int = Field(ge=1, le=10, description="Well-written and understandable")    reasoning: str = Field(description="Brief explanation") async def llm_judge_quality(    response: str,    question: str,    context: str = None) -> QualityRating:    """Use Claude to judge response quality."""    client = Anthropic()     system = """You are an expert evaluator of AI responses.    Rate responses on accuracy, helpfulness, and clarity (1-10 scale).    Provide brief reasoning for your ratings."""     prompt = f"""Rate the following response: Question: {question}{f'Context: {context}' if context else ''}Response: {response} Provide ratings in JSON format:{{  "accuracy": <1-10>,  "helpfulness": <1-10>,  "clarity": <1-10>,  "reasoning": "<brief explanation>"}}"""     message = client.messages.create(        model="claude-sonnet-4-6",        max_tokens=500,        system=system,        messages=[{"role": "user", "content": prompt}]    )     return QualityRating(**json.loads(message.content[0].text))``` ### Pairwise Comparison ```pythonfrom pydantic import BaseModel, Fieldfrom typing import Literal class ComparisonResult(BaseModel):    winner: Literal["A", "B", "tie"]    reasoning: str    confidence: int = Field(ge=1, le=10) async def compare_responses(    question: str,    response_a: str,    response_b: str) -> ComparisonResult:    """Compare two responses using LLM judge."""    client = Anthropic()     prompt = f"""Compare these two responses and determine which is better. Question: {question} Response A: {response_a} Response B: {response_b} Consider accuracy, helpfulness, and clarity. Answer with JSON:{{  "winner": "A" or "B" or "tie",  "reasoning": "<explanation>",  "confidence": <1-10>}}"""     message = client.messages.create(        model="claude-sonnet-4-6",        max_tokens=500,        messages=[{"role": "user", "content": prompt}]    )     return ComparisonResult(**json.loads(message.content[0].text))``` ### Reference-Based Evaluation ```pythonclass ReferenceEvaluation(BaseModel):    semantic_similarity: float = Field(ge=0, le=1)    factual_accuracy: float = Field(ge=0, le=1)    completeness: float = Field(ge=0, le=1)    issues: list[str] async def evaluate_against_reference(    response: str,    reference: str,    question: str) -> ReferenceEvaluation:    """Evaluate response against gold standard reference."""    client = Anthropic()     prompt = f"""Compare the response to the reference answer. Question: {question}Reference Answer: {reference}Response to Evaluate: {response} Evaluate:1. Semantic similarity (0-1): How similar is the meaning?2. Factual accuracy (0-1): Are all facts correct?3. Completeness (0-1): Does it cover all key points?4. List any specific issues or errors. Respond in JSON:{{  "semantic_similarity": <0-1>,  "factual_accuracy": <0-1>,  "completeness": <0-1>,  "issues": ["issue1", "issue2"]}}"""     message = client.messages.create(        model="claude-sonnet-4-6",        max_tokens=500,        messages=[{"role": "user", "content": prompt}]    )     return ReferenceEvaluation(**json.loads(message.content[0].text))``` ## Human Evaluation Frameworks ### Annotation Guidelines ```pythonfrom dataclasses import dataclass, fieldfrom typing import Optional @dataclassclass AnnotationTask:    """Structure for human annotation task."""    response: str    question: str    context: Optional[str] = None     def get_annotation_form(self) -> dict:        return {            "question": self.question,            "context": self.context,            "response": self.response,            "ratings": {                "accuracy": {                    "scale": "1-5",                    "description": "Is the response factually correct?"                },                "relevance": {                    "scale": "1-5",                    "description": "Does it answer the question?"                },                "coherence": {                    "scale": "1-5",                    "description": "Is it logically consistent?"                }            },            "issues": {                "factual_error": False,                "hallucination": False,                "off_topic": False,                "unsafe_content": False            },            "feedback": ""        }``` ### Inter-Rater Agreement ```pythonfrom sklearn.metrics import cohen_kappa_score def calculate_agreement(    rater1_scores: list[int],    rater2_scores: list[int]) -> dict:    """Calculate inter-rater agreement."""    kappa = cohen_kappa_score(rater1_scores, rater2_scores)     if kappa < 0:        interpretation = "Poor"    elif kappa < 0.2:        interpretation = "Slight"    elif kappa < 0.4:        interpretation = "Fair"    elif kappa < 0.6:        interpretation = "Moderate"    elif kappa < 0.8:        interpretation = "Substantial"    else:        interpretation = "Almost Perfect"     return {        "kappa": kappa,        "interpretation": interpretation    }``` ## A/B Testing ### Statistical Testing Framework ```pythonfrom scipy import statsimport numpy as npfrom dataclasses import dataclass, field @dataclassclass ABTest:    variant_a_name: str = "A"    variant_b_name: str = "B"    variant_a_scores: list[float] = field(default_factory=list)    variant_b_scores: list[float] = field(default_factory=list)     def add_result(self, variant: str, score: float):        """Add evaluation result for a variant."""        if variant == "A":            self.variant_a_scores.append(score)        else:            self.variant_b_scores.append(score)     def analyze(self, alpha: float = 0.05) -> dict:        """Perform statistical analysis."""        a_scores = np.array(self.variant_a_scores)        b_scores = np.array(self.variant_b_scores)         # T-test        t_stat, p_value = stats.ttest_ind(a_scores, b_scores)         # Effect size (Cohen's d)        pooled_std = np.sqrt((np.std(a_scores)**2 + np.std(b_scores)**2) / 2)        cohens_d = (np.mean(b_scores) - np.mean(a_scores)) / pooled_std         return {            "variant_a_mean": np.mean(a_scores),            "variant_b_mean": np.mean(b_scores),            "difference": np.mean(b_scores) - np.mean(a_scores),            "relative_improvement": (np.mean(b_scores) - np.mean(a_scores)) / np.mean(a_scores),            "p_value": p_value,            "statistically_significant": p_value < alpha,            "cohens_d": cohens_d,            "effect_size": self._interpret_cohens_d(cohens_d),            "winner": self.variant_b_name if np.mean(b_scores) > np.mean(a_scores) else self.variant_a_name        }     @staticmethod    def _interpret_cohens_d(d: float) -> str:        """Interpret Cohen's d effect size."""        abs_d = abs(d)        if abs_d < 0.2:            return "negligible"        elif abs_d < 0.5:            return "small"        elif abs_d < 0.8:            return "medium"        else:            return "large"``` ## Regression Testing ### Regression Detection ```pythonfrom dataclasses import dataclass @dataclassclass RegressionResult:    metric: str    baseline: float    current: float    change: float    is_regression: bool class RegressionDetector:    def __init__(self, baseline_results: dict, threshold: float = 0.05):        self.baseline = baseline_results        self.threshold = threshold     def check_for_regression(self, new_results: dict) -> dict:        """Detect if new results show regression."""        regressions = []         for metric in self.baseline.keys():            baseline_score = self.baseline[metric]            new_score = new_results.get(metric)             if new_score is None:                continue             # Calculate relative change            relative_change = (new_score - baseline_score) / baseline_score             # Flag if significant decrease            is_regression = relative_change < -self.threshold            if is_regression:                regressions.append(RegressionResult(                    metric=metric,                    baseline=baseline_score,                    current=new_score,                    change=relative_change,                    is_regression=True                ))         return {            "has_regression": len(regressions) > 0,            "regressions": regressions,            "summary": f"{len(regressions)} metric(s) regressed"        }``` ## LangSmith Evaluation Integration ```pythonfrom langsmith import Clientfrom langsmith.evaluation import evaluate, LangChainStringEvaluator # Initialize LangSmith clientclient = Client() # Create datasetdataset = client.create_dataset("qa_test_cases")client.create_examples(    inputs=[{"question": q} for q in questions],    outputs=[{"answer": a} for a in expected_answers],    dataset_id=dataset.id) # Define evaluatorsevaluators = [    LangChainStringEvaluator("qa"),           # QA correctness    LangChainStringEvaluator("context_qa"),   # Context-grounded QA    LangChainStringEvaluator("cot_qa"),       # Chain-of-thought QA] # Run evaluationasync def target_function(inputs: dict) -> dict:    result = await your_chain.ainvoke(inputs)    return {"answer": result} experiment_results = await evaluate(    target_function,    data=dataset.name,    evaluators=evaluators,    experiment_prefix="v1.0.0",    metadata={"model": "claude-sonnet-4-6", "version": "1.0.0"}) print(f"Mean score: {experiment_results.aggregate_metrics['qa']['mean']}")``` ## Benchmarking ### Running Benchmarks ```pythonfrom dataclasses import dataclassimport numpy as np @dataclassclass BenchmarkResult:    metric: str    mean: float    std: float    min: float    max: float class BenchmarkRunner:    def __init__(self, benchmark_dataset: list[dict]):        self.dataset = benchmark_dataset     async def run_benchmark(        self,        model,        metrics: list[Metric]    ) -> dict[str, BenchmarkResult]:        """Run model on benchmark and calculate metrics."""        results = {metric.name: [] for metric in metrics}         for example in self.dataset:            # Generate prediction            prediction = await model.predict(example["input"])             # Calculate each metric            for metric in metrics:                score = metric.fn(                    prediction=prediction,                    reference=example["reference"],                    context=example.get("context")                )                results[metric.name].append(score)         # Aggregate results        return {            metric: BenchmarkResult(                metric=metric,                mean=np.mean(scores),                std=np.std(scores),                min=min(scores),                max=max(scores)            )            for metric, scores in results.items()        }```