# Custom Stack FT Lab: Repo-Tuned Model on Mid-Size Repo (~50K LoC)

> Source: https://sukruyusufkaya.com/en/learn/fine-tuning-cookbook/ftc-custom-stack-repo-tuned-model
> Updated: 2026-05-14T14:42:55.752Z
> Category: Fine-Tuning Cookbook (Model-by-Model)
> Module: Part VIII — Code Models & Repo-Level FT
**TLDR:** FT for company internal codebase: 50K LoC Python+TypeScript repo. File hierarchy preservation, internal symbol awareness, test file pairing, commit history mining (good/bad code), 7B model 4-6h FT on RTX 4090.