RAG over a codebase: why retrieving code needs a different chunking strategy

Chunking code by token count the same way you'd chunk prose breaks function boundaries and destroys context. A code-aware retrieval pipeline needs a different approach.

At a formal campus event
At a formal campus event

Chunking a codebase by a fixed token count, the same way you'd chunk an article, routinely splits a function in half — and a half-function chunk is nearly useless for a 'how does X work' question.

Chunk by structure, not by token count

  • Parse the code (using the language's AST or a simple structural parser) and chunk by function or class boundary, not by arbitrary token windows.
  • Include a function's signature and docstring even when the body is chunked separately, so retrieval has something to match against beyond raw logic.
  • Index file paths and import relationships as metadata — 'where is this function called from' is a common real question retrieval alone can't answer without that structure.

What this enables

A code-aware RAG assistant that retrieves whole, coherent functions answers 'how does X work' meaningfully better than one retrieving arbitrary fifty-line windows that cut across logic.

See RAG chunking strategies, a guide.

RAGCode retrievalChunking
Pranjul Rathour
Pranjul Rathour
GenAI Engineer · Kanpur, Uttar Pradesh, India

GenAI engineer and AI product builder with 2+ years shipping production-grade AI systems: RAG pipelines, fine-tuned LLMs, hybrid retrieval and multi-modal apps across vision, speech and OCR, architected end to end from ingestion to deployment. Leads engineering for SCULT INDIA's 14-member team, founded the 500+ member TechVerse Enclave community and has mentored 200+ students. Three hackathon first prizes: Changethon 2025 (IIT Roorkee), Product Genesis at Vividhotsava 2025 (CSJMU Kanpur) and BYTEBATTLE (MeetKats).

Open to GenAI roles, hackathon judging, mentorship sessions and guest talks at colleges. Email pranjulrathour41@gmail.com.

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Pranjul Rathour, GenAI engineer in Kanpur