The 5-File AI Project Setup That Saves Me Hours Every Week

Every time I start a new project with an AI assistant, I used to spend the first 20 minutes re-explaining everything: the tech stack, the coding style, the project structure, what we tried yesterday. Then I started keeping 5 files at the root of every project. Now my assistant is productive in under a minute. The 5 Files 1. PROJECT.md — What This Thing Is A one-paragraph summary plus the current state: # Widget Dashboard React + TypeScript frontend, Express API, PostgreSQL. Currently: MVP is deployed. Working on user auth (OAuth2 via Google). Last session: finished the login flow, need to add refresh tokens. This replaces the "okay so this is a React app and we're building..." preamble. The assistant reads it and knows where we are. 2. STACK.md — Versions and Dependencies - Node 20.11, TypeScript 5.3 - React 18.2, Vite 5.1 - Express 4.18, Prisma 5.8 - PostgreSQL 16 - Testing: Vitest + Playwright - Formatting: Prettier (2-space indent, no semicolons) This prevents the assistant from gen