This article covers the second layer of the full-stack architecture: the Chunking Service. Chunking strategy sets the ceiling for retrieval quality — no matter how good upstream parsing is, if chunking is wrong, nothing downstream can fix it. Core engineering insight: chunking is not a parameter tuning problem. It's a judgment problem about what constitutes the minimum semantic unit of a document.
0. The Pain Point
The first version of the system used a single chunking strategy across all documents:
Fixed 512-character chunks for everything.
Miss rate: 15%. Retrieval kept returning semantically incomplete chunks — the content was there, but only half of it.






