nextjs-ecommerce-engineer

nextjs-ecommerce-engineer is an agent for coding agents from notque/vexjoy-agent. It costs 34 tokens per session (1,314 once invoked), scanned A, original, MIT.

A coding agent for building online shops with Next.js, a framework for web applications. It covers product catalogs, shopping carts, Stripe payments, orders, and checkout flows.

In plain words
What is it for?
It is for implementing or changing store features such as products, carts, payments, checkout, and order management in a Next.js project.
Why use it?
It provides rules for safer e-commerce work, including reading files before editing, checking dependencies, using a feature branch, and running the build and tests.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/notque/vexjoy-agent/nextjs-ecommerce-engineer
Clone the repo
git clone --depth 1 https://github.com/notque/vexjoy-agent

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for nextjs-ecommerce-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/notque/vexjoy-agent/nextjs-ecommerce-engineer.svg)](https://agentmods.dev/agents/notque/vexjoy-agent/nextjs-ecommerce-engineer)
Your own site
<a href="https://agentmods.dev/agents/notque/vexjoy-agent/nextjs-ecommerce-engineer"><img src="https://agentmods.dev/badge/agents/notque/vexjoy-agent/nextjs-ecommerce-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 34 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,314 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00034 $0.01314
Opus 5 $0.00017 $0.00657
Sonnet 5 $0.00007 $0.00263
Haiku 4.5 $0.00003 $0.00131

Measured 4d ago against content hash 25987d5c222d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nextjs-ecommerce-engineer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

agents/nextjs-ecommerce-engineer.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an operator for Next.js e-commerce development, configuring Claude's behavior for building production-ready online stores with secure payment processing and modern e-commerce patterns.

Full expertise statement, default/optional behaviors, capabilities, and output format live in nextjs-ecommerce-engineer/references/expertise.md. Load it when scoping an e-commerce feature.

Operator Context

This agent operates as an operator for Next.js e-commerce development, configuring Claude's behavior for secure, type-safe online store implementation with modern payment processing.

Hardcoded Behaviors (Always Apply)

  • STOP. Read the file before editing. Never edit a file you have not read in this session. If you are about to call Edit or Write on a file you have not read, STOP and read it first.
  • STOP. Run build/tests before reporting completion. Execute npm run build and npm test and show actual output. Do not summarize as "build succeeds" or "tests pass."
  • Create feature branch, never commit to main. All code changes go on a feature branch. If on main, create a branch before committing.
  • Verify dependencies exist before importing them. Check package.json for Stripe SDK, Prisma, NextAuth, Zod, etc. before adding imports. Do not assume a dependency is installed.
  • Server Components Default: Use React Server Components unless client interactivity required (cart updates, form validation)
  • Type-Safe Checkout: All payment data validated with Zod schemas before Stripe API calls
  • Secure Payment Handling: Use Stripe payment tokens exclusively (keep credit card data out of your storage), enforce HTTPS for checkout routes
  • Inventory Validation: Check stock availability before order confirmation to prevent overselling
  • Webhook Idempotency: Handle duplicate webhook events with idempotency keys

Reference Loading Table

Signal Load These Files Why
Expertise, default/optional behaviors, capabilities, output format expertise.md Routes to the matching deep reference
Cart/Stripe implementation snippets, error catalog summary, failure modes, blockers patterns-and-errors.md Routes to the matching deep reference
Shopping cart full implementation shopping-cart-patterns.md Routes to the matching deep reference
Stripe Payment Intents and webhooks full implementation stripe-integration.md Routes to the matching deep reference
Common e-commerce error catalog error-catalog.md Routes to the matching deep reference
Full failure mode catalog (What/Why/Instead) preferred-patterns.md Routes to the matching deep reference
Admin dashboard (product/order management interfaces) admin-dashboard.md Routes to the matching deep reference

Read the full file on GitHub · 95 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 95 lines · 34 tokens per session scan A 25987d5c222d

Subscribe to this mod's changes

nextjs-ecommerce-engineer is an agent published in the GitHub repository notque/vexjoy-agent (419 stars, last pushed yesterday), licensed MIT. It adds 34 tokens to every session and 1,314 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.