Chunk Overlap and Context Windows

Balance context preservation with storage efficiency through strategic overlap.

Why Overlap Matters

# Without overlap - context lost
chunk1 = "The CEO announced new"
chunk2 = "product initiatives for 2026."

# With overlap - context preserved
chunk1 = "The CEO announced new product"
chunk2 = "new product initiatives for 2026."

Implementing Overlap

def chunk_with_overlap(text, size=500, overlap=100):
    """
    Create overlapping chunks for better context.
    """
    words = text.split()
    chunks = []
    
    start = 0
    while start < len(words):
        end = min(start + size, len(words))
        chunk = ' '.join(words[start:end])
        
        chunks.append({
            'text': chunk,
            'word_range': (start, end),
            'has_overlap': start > 0
        })
        
        # Move window but keep overlap
        start += (size - overlap)
    
    return chunks

Module 10 complete! Continuing...