Agent Skills for TypeScript & Next.js Developers: Install, Use, and Create Custom Skills (2026)

4. Create a Custom Skill for Your Stack

Highest ROI skills encode patterns your team already fights about.

Step 1 — Create the directory

mkdir -p .agents/skills/nextjs-prisma-dal

Step 2 — Write SKILL.md

---
name: nextjs-prisma-dal
description: Enforce the Data Access Layer pattern for Next.js + Prisma. Use when writing Server Actions, API routes, Prisma queries, or ownership checks.
---

# Next.js + Prisma Data Access Layer

## Non-negotiable architecture
- Prisma client lives only in lib/prisma.ts (singleton).
- All database access goes through data/ modules marked server-only.
- Server Actions stay thin: validate, auth, DAL, map to DTO.

## Ownership
Every query that returns user data must include the authenticated user id in the WHERE clause.

## Example
// data/projects.ts
import "server-only"
import { prisma } from "@/lib/prisma"

export async function getProjectForUser(projectId: string, userId: string) {
  return prisma.project.findFirst({
    where: { id: projectId, ownerId: userId },
    select: { id: true, name: true, updatedAt: true },
  })
}

Step 3 — Verify triggering

Restart the agent and ask it to add a create-project Server Action. A well-written description should cause the skill to load automatically.