Hybrid Search & Chunk Stitching: Advanced RAG with Custom-GPT Actions in Go
Custom GPT Actions let us expose an API that ChatGPT calls on behalf of users. We build the backend — ChatGPT handles the frontend: web, mobile, voice, message history, auth. But a production-grade RAG backend needs more than basic vector search. This article covers building a high-performance Custom GPT in Go, along with the interesting parts: hybrid search with Reciprocal Rank Fusion, chunk stitching for contiguous context, query-focused summarization with SLMs, and decoupled embedding strategies for A/B testing. ...