catatz: Skill for Codex

.agents/skills/nextjs-turbopack/SKILL.md

nextjs-turbopack is a skill for Codex from kupzed/catatz. It costs 39 tokens per session (517 once invoked), scanned A, a copy of nextjs-turbopack, MIT.

A guide to using Turbopack, Next.js’s Rust-based bundler, for faster local development and incremental builds.

In plain words
What is it for?
It covers Next.js development, file-system caching, hot updates, production builds, and when to use webpack instead.
Why use it?
It helps developers choose between Turbopack and webpack and diagnose slow startup, hot updates, or bundle work in Next.js projects.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: installed under .agents/ (shared by several agents).

This is kupzed/catatz's own configuration. It tells Codex how to work on catatz itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything catatz configures →

Reuse

Borrowing it

Nothing to install: this file belongs to kupzed/catatz. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/kupzed/catatz/master/.agents/skills/nextjs-turbopack/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/kupzed/catatz

Made for: Codex.

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-turbopack

README.md
[![agentmods](https://agentmods.dev/badge/skills/kupzed/catatz/nextjs-turbopack/github.svg)](https://agentmods.dev/skills/kupzed/catatz/nextjs-turbopack)
Your own site
<a href="https://agentmods.dev/skills/kupzed/catatz/nextjs-turbopack"><img src="https://agentmods.dev/badge/skills/kupzed/catatz/nextjs-turbopack/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for nextjs-turbopack

Your own site · 80×15
<a href="https://agentmods.dev/skills/kupzed/catatz/nextjs-turbopack"><img src="https://agentmods.dev/badge/skills/kupzed/catatz/nextjs-turbopack.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 517 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 100% copy Near-identical to another mod 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 5.1 $0.00039 $0.00517
Opus 5 $0.00019 $0.00259
Sonnet 5 $0.00008 $0.00103
Haiku 4.5 $0.00004 $0.00052

Measured 7d ago against content hash e35a6a043017, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

nextjs-turbopack 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 7d 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.

Origin

This is a copy

100% identical to nextjs-turbopack — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/nextjs-turbopack/SKILL.md · 44 lines

What it actually says

Next.js and Turbopack

Next.js 16+ uses Turbopack by default for local development: an incremental bundler written in Rust that significantly speeds up dev startup and hot updates.

When to Use

  • Turbopack (default dev): Use for day-to-day development. Faster cold start and HMR, especially in large apps.
  • Webpack (legacy dev): Use only if you hit a Turbopack bug or rely on a webpack-only plugin in dev. Disable with --webpack (or --no-turbopack depending on your Next.js version; check the docs for your release).
  • Production: Production build behavior (next build) may use Turbopack or webpack depending on Next.js version; check the official Next.js docs for your version.

Use when: developing or debugging Next.js 16+ apps, diagnosing slow dev startup or HMR, or optimizing production bundles.

How It Works

  • Turbopack: Incremental bundler for Next.js dev. Uses file-system caching so restarts are much faster (e.g. 5–14x on large projects).
  • Default in dev: From Next.js 16, next dev runs with Turbopack unless disabled.
  • File-system caching: Restarts reuse previous work; cache is typically under .next; no extra config needed for basic use.
  • Bundle Analyzer (Next.js 16.1+): Experimental Bundle Analyzer to inspect output and find heavy dependencies; enable via config or experimental flag (see Next.js docs for your version).

Examples

Commands

next dev
next build
next start

Usage

Run next dev for local development with Turbopack. Use the Bundle Analyzer (see Next.js docs) to optimize code-splitting and trim large dependencies. Prefer App Router and server components where possible.

Best Practices

  • Stay on a recent Next.js 16.x for stable Turbopack and caching behavior.
  • If dev is slow, ensure you're on Turbopack (default) and that the cache isn't being cleared unnecessarily.
  • For production bundle size issues, use the official Next.js bundle analysis tooling for your version.
Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 7d ago First seen · 44 lines · 39 tokens per session scan A e35a6a043017

Subscribe to this mod's changes

nextjs-turbopack is a skill published in the GitHub repository kupzed/catatz (33 stars, last pushed 7d ago), licensed MIT. It adds 39 tokens to every session and 517 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to nextjs-turbopack, differing in 0 lines, and is treated as a copy.

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