GreenField

Ship a Next.js + Android product on Firebase without spending your first week deciding auth, quotas, billing and CI.

GreenField is an operating manual for AI coding agents: 104 notes of prescriptive standards, 22 decision records, and 61 copy-ready configuration files. You point an agent at it; the agent builds the product.

The problem

Starter kits hand you a running page and leave every expensive decision open:

• How does auth work across a browser and an Android app, from one user record?
• Where are model provider keys allowed to exist, and who enforces the spend limit?
• What happens when a billing webhook is delivered twice?
• Which side owns the schema when the web app and the Android app disagree?
• What has to be true before the Play Store lets you publish at all?

You answer these under deadline pressure, once per product, usually wrong the first time. An AI agent asked to answer them will invent something plausible and different every run.

GreenField answers them once, in writing, and hands the answers to the agent as a contract.

What GreenField is

Not a demo app. Not a one-click starter that pretends to ship a finished product.

It is a manual with a materializer: locked architectural decisions, runbooks whose order matters, and templates that write your repository's configuration contract.

What actually lands in your repository

Materialization writes 61 files. No application source — configuration, contracts, and the agent's instructions:

my-product/
├── AGENTS.md                     the contract your agent must obey
├── package.json                  pnpm workspace + Turborepo pipeline
├── packages/contracts/           Zod + JSON Schema — cross-platform source of truth
├── apps/web/                     Next.js: middleware, Vitest, Playwright, App Hosting
│   ├── apphosting.yaml           production back