Imported from ERP-PreFg-Admin/ERP-Prefg-Tool (erp_project/AGENTS.md). Install upstream with npx skills add ERP-PreFg-Admin/ERP-Prefg-Tool --skill erp_project. Copyright stays with the author.

ERP Project Agent Instructions

Next.js 16 App Router + React 19 + TypeScript + Tailwind CSS v4, on MySQL 8.0 (AWS RDS) via mysql2. Prisma 7 is present but schema-only.

CLAUDE.md is the detailed reference. This file is the short version; where the two disagree, CLAUDE.md wins.

What matters here

• Keep changes aligned with the App Router structure in app/ and the SQL in lib/queries/.
• Database access goes through query / execute / pool from lib/db.ts. Prisma Client is never used at runtime — there is no Prisma singleton.
• Do not edit generated files under app/generated/prisma/.
• Table names were renamed in 2026-08 and prisma/schema.prisma was not updated. Check lib/queries/*.ts for the real name, or the mapping in CLAUDE.md — never the Prisma schema.
• API routes live under app/api/v1/. /api/auth and /api/health stay unversioned; external systems address them by URL.

Commands to use

• npm run dev — start the app
• npm run build — verify production build
• npm run lint — full ESLint (~220 pre-existing problems)
• npm run lint:changed — ESLint on changed files only; this is the gate
• npm test — unit tests (node:test, no DB, no credentials)
• npm run test:db — DB tests, each rolled back

Two gotchas worth knowing before you trust a green check:

• npx tsc --noEmit can report clean on a file npm run build then rejects — tsconfig.json has "incremental": true and a stale tsconfig.tsbuildinfo skips it. Use --incremental false when it matters.
• npm run build refuses to start while npm run dev is running; Next 16 takes a single lock on .next.
• A unit test may only import pure modules. Anything reaching lib/db, lib/s3 or lib/mail/mailer throws at import without credentials, which is why logic worth testing gets extracted (lib/po-split.ts, lib/invoice/invoice-merge.ts, lib/invoice/invoice-mail-step.ts, lib/mail/recipients.ts, lib/mail/mail-limits.ts, lib/po/po-rules.ts, lib/masters/kit-sku.ts, lib/masters/variant-rm-lock.ts, app/po-tracking/mfg-overview/mapping-state.ts).

There is no db:test / db:generate / db:migrate / db:push / db:seed npm alias, despite older docs referencing them. Prisma is invoked as raw npx prisma …, and migrations in practice are the hand-written prisma/*.sql files applied directly to RDS.

Working conventions

• Prefer TypeScript and existing Next.js patterns over ad-hoc scripts.
• Verify a table or column name against lib/queries/ before using it — the rename left four columns deliberately spelled bom_*.
• Keep database access centralized in lib/db.ts; never import from app/generated/prisma/client in application code.
• DB config comes from DB_HOST / DB_USER / DB_PASSWORD / DB_NAME_TEST | DB_NAME_PROD (see lib/env.ts), not DATABASE_URL.

This project uses a newer Next.js stack than older training examples. If you encounter unexpected behavior, consult the local Next.js docs in node_modules/next/dist/docs/ before making assumptions.