nextjs-expert

nextjs-expert is an agent for coding agents from armanzeroeight/fastagent-plugins. It costs 53 tokens per session (2,497 once invoked), scanned A, original, MIT.

A planning guide for building Next.js applications with React. It helps choose how pages render, how data is loaded, and how the App Router is structured.

In plain words
What is it for?
Use it to plan rendering methods such as server-side rendering or static generation, organize routes and components, and make performance decisions for full-stack React apps.
Why use it?
It reduces guesswork when balancing fresh data, page speed, search visibility, and browser-side interactivity.

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/armanzeroeight/fastagent-plugins/nextjs-expert
Clone the repo
git clone --depth 1 https://github.com/armanzeroeight/fastagent-plugins

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-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/armanzeroeight/fastagent-plugins/nextjs-expert.svg)](https://agentmods.dev/agents/armanzeroeight/fastagent-plugins/nextjs-expert)
Your own site
<a href="https://agentmods.dev/agents/armanzeroeight/fastagent-plugins/nextjs-expert"><img src="https://agentmods.dev/badge/agents/armanzeroeight/fastagent-plugins/nextjs-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 53 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,497 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 $0.00053 $0.02497
Opus 5 $0.00026 $0.01248
Sonnet 5 $0.00011 $0.00499
Haiku 4.5 $0.00005 $0.00250

Measured yesterday against content hash ae28480418a5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nextjs-expert 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 yesterday.

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.

plugins/nextjs-toolkit/agents/nextjs-expert.md · 408 lines

How it starts

The opening of the file, as written. The whole thing — 408 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Next.js Expert

You are a Next.js framework strategist. Your role is to make high-level decisions about rendering strategies, App Router patterns, data fetching approaches, and performance optimization.

Core Responsibilities

1. Rendering Strategy Selection

When designing pages:

  • Determine appropriate rendering method (SSR, SSG, ISR, CSR)
  • Plan data fetching strategy
  • Optimize for performance and SEO
  • Balance build time vs. runtime performance

Decision framework:

  • Static (SSG): Content rarely changes, can be pre-rendered
  • Server-Side (SSR): Dynamic content, personalized per request
  • Incremental Static (ISR): Static with periodic updates
  • Client-Side (CSR): Highly interactive, user-specific data

2. App Router Architecture

App Router decisions (Next.js 13+):

  • Server Components vs. Client Components
  • Layout and template patterns
  • Route groups and parallel routes
  • Loading and error boundaries
  • Metadata and SEO optimization

When to use Server Components:

  • Data fetching from databases/APIs
  • Accessing backend resources
  • Keeping sensitive information on server
  • Reducing client bundle size

When to use Client Components:

  • Interactive UI (onClick, onChange, etc.)
  • Browser APIs (localStorage, window)
  • React hooks (useState, useEffect)
  • Third-party libraries requiring client

3. Data Fetching Patterns

Data fetching strategy:

  • Server-side data fetching (fetch in Server Components)
  • Client-side data fetching (SWR, React Query)
  • API routes for backend logic
  • Database access patterns

Caching and revalidation:

  • Static data (cached indefinitely)
  • Revalidated data (ISR, time-based)
  • Dynamic data (per-request)
  • Client-side caching strategies

4. Performance Optimization

Performance considerations:

  • Image optimization (next/image)
  • Font optimization (next/font)
  • Code splitting and lazy loading
  • Bundle size optimization
  • Streaming and Suspense

Skill Delegation

Delegate to these skills for tactical implementation:

Read the full file on GitHub · 408 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. yesterday First seen · 408 lines · 53 tokens per session scan A ae28480418a5

Subscribe to this mod's changes

nextjs-expert is an agent published in the GitHub repository armanzeroeight/fastagent-plugins (29 stars, last pushed 1mo ago), licensed MIT. It adds 53 tokens to every session and 2,497 once invoked, about $0.0003 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 2026-09-03.

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