A Complete Practical Guide to Building a Domain-Specific BJJ AI Coach

The author details a complete engineering pipeline for training a specialized Brazilian Jiu-Jitsu model, bjj-coach-7b-v3, and a reranker on a single GPU using video and document libraries. The system uses Whisper for transcription error correction and prepends context headers to enrich data, integrates knowledge graph logic with Qwen2.5-VL-7B to extract silent action frames, and fine-tunes bge-reranker with a 5-way listwise loss before exporting it as an ONNX service.