nextjs-i18n

nextjs-i18n is a skill for Claude Code, Codex from fusengine/agents. It costs 35 tokens per session (1,529 once invoked), scanned A, original, MIT.

A guide to adding multiple languages to Next.js 16 applications. It covers language-based URLs, translated navigation, date and number formatting, right-to-left languages, and search-engine language metadata.

In plain words
What is it for?
Use it when building language switches, translated routes, localized dates or currencies, right-to-left layouts, or multilingual SEO.
Why use it?
It removes the need to design language routing and translation behavior from scratch. It helps pages, links, errors, and metadata stay consistent across languages.

Skill for Claude CodeCodex

Part of the fuse-nextjs plugin — 11 skills, 1 agent shipped together

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 skills/fusengine/agents/nextjs-i18n
Any agent
npx skills add fusengine/agents --skill nextjs-i18n
Clone the repo
git clone --depth 1 https://github.com/fusengine/agents

Made for: Claude Code, Codex.

Or install fuse-nextjs, the plugin that ships this one along with the rest of its 11 skills, 1 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-i18n

README.md
[![agentmods](https://agentmods.dev/badge/skills/fusengine/agents/nextjs-i18n.svg)](https://agentmods.dev/skills/fusengine/agents/nextjs-i18n)
Your own site
<a href="https://agentmods.dev/skills/fusengine/agents/nextjs-i18n"><img src="https://agentmods.dev/badge/skills/fusengine/agents/nextjs-i18n.svg" alt="Measured on agentmods" height="20"></a>
Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,529 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 $0.00035 $0.01529
Opus 5 $0.00017 $0.00764
Sonnet 5 $0.00007 $0.00306
Haiku 4.5 $0.00003 $0.00153

Measured yesterday against content hash eee5eafd4568, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nextjs-i18n 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-expert/skills/nextjs-i18n/SKILL.md · 167 lines

How it starts

The opening of the file, as written. The whole thing — 167 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Covers [locale]-prefixed routing, localized navigation components (Link, redirect, usePathname, useRouter), date/number/currency/relative-time formatting, RTL language support, SEO hreflang tags, and localized special files ([locale]/error.tsx, [locale]/not-found.tsx, global-error.tsx). This is the Next.js-specific i18n skill (App Router routing, proxy.ts integration) — for plain React apps without Next.js see react-i18n, and for Astro see astro-i18n.

Next.js 16 Internationalization

Complete i18n solution with next-intl or DIY dictionary approach.

Agent Workflow (MANDATORY)

Before ANY implementation, use TeamCreate to spawn 3 agents:

  1. fuse-ai-pilot:explore-codebase - Analyze existing i18n setup and message files
  2. fuse-ai-pilot:research-expert - Verify latest next-intl docs via Context7/Exa
  3. mcp__context7__query-docs - Check locale config and patterns

After implementation, run fuse-ai-pilot:sniper for validation.


Overview

When to Use

  • Building multilingual Next.js 16 applications
  • Need locale-based routing with [locale] dynamic segment
  • Implementing language switcher and URL localization
  • Formatting dates, numbers, currencies, and relative times per locale
  • SEO optimization with hreflang tags and localized metadata
  • Supporting right-to-left (RTL) languages

Why next-intl

Feature Benefit
App Router native Full Server Components support
Type-safe messages TypeScript autocompletion for keys
ICU MessageFormat Pluralization, gender, select expressions
Async message loading Load translations on-demand per locale
proxy.ts compatible Works with Next.js 16 proxy pattern
Rich formatting Dates, numbers, lists, relative time

Read the full file on GitHub · 167 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 · 167 lines · 35 tokens per session scan A eee5eafd4568

Subscribe to this mod's changes

nextjs-i18n is a skill published in the GitHub repository fusengine/agents (25 stars, last pushed 1mo ago), licensed MIT. It adds 35 tokens to every session and 1,529 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 2026-09-03.

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