AI article
LangChain chunk_overlap=200: 2,181 of 4,155 Chunks Got No Overlap
Community description: LangChain chunk_overlap is a ceiling, not a guarantee: 52% of seams in my 452 posts had 0 overlap. The cause, plus 2 measured fixes.
Dev.to | Nov 6, 2026 | jidonglab
Automated excerpt
At chunk_size=1000, chunk_overlap=200, 2,181 of 4,155 seams (52.5%) had 0 characters of overlap. Why does LangChain chunk_overlap produce no overlap? Pieces are paragraphs by default, so any seam whose last paragraph exceeds 200 characters gets no overlap, silently.
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