Chunking Quality Evaluator

Build an evaluation system for chunking strategy quality.

## Document Corpus
{{corpus_description}}

## Chunking Strategies
{{chunking_strategies}}

## Evaluation Criteria
{{evaluation_criteria}}

Implement evaluation:

```python
class ChunkingEvaluator:
    def evaluate_coherence(self, chunks: List[str]) -> float:
        """Score semantic coherence within chunks"""
        pass
    
    def evaluate_completeness(self, chunks: List[str], queries: List[str]) -> float:
        """Score information completeness for queries"""
        pass
    
    def evaluate_boundary_quality(self, chunks: List[str]) -> float:
        """Score chunk boundary appropriateness"""
        pass
    
    def run_retrieval_eval(self, chunks: List[str], qa_pairs: List[QAPair]) -> RetrievalMetrics:
        """End-to-end retrieval evaluation"""
        pass
```

Metrics:
- Intra-chunk coherence
- Cross-chunk information preservation
- Retrieval effectiveness
- Token efficiency

Include automated comparison framework.