Internationalization I18n Skill for Claude

Implements multi-language support using i18next, gettext, or Intl API with translation workflows and RTL support. Use when building multilingual applications, handling date/currency formatting, or supporting right-to-left languages.

2k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

202

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/secondsky/claude-skills --skill internationalization-i18n

The instruction itself

7 sections, as written by the author

Internationalization (i18n)

Implement multi-language support with proper translation management and formatting.

i18next Setup (React)

import i18n from 'i18next';
import { initReactI18next } from 'react-i18next';
import LanguageDetector from 'i18next-browser-languagedetector';

i18n
  .use(LanguageDetector)
  .use(initReactI18next)
  .init({
    fallbackLng: 'en',
    interpolation: { escapeValue: false },
    resources: {
      en: { translation: { welcome: 'Welcome, {{name}}!' } },
      es: { translation: { welcome: '¡Bienvenido, {{name}}!' } }
    }
  });

// Usage
const { t } = useTranslation();
<h1>{t('welcome', { name: 'John' })}</h1>

Pluralization

// Translation file
{
  "items": "{{count}} item",
  "items_plural": "{{count}} items",
  "items_zero": "No items"
}

// Usage
t('items', { count: 0 })  // "No items"
t('items', { count: 1 })  // "1 item"
t('items', { count: 5 })  // "5 items"

Date/Number Formatting

// Dates
new Intl.DateTimeFormat('de-DE', {
  dateStyle: 'long',
  timeStyle: 'short'
}).format(new Date());

// Numbers
new Intl.NumberFormat('en-US', {
  style: 'currency',
  currency: 'USD'
}).format(1234.56);  // "$1,234.56"

// Relative time
new Intl.RelativeTimeFormat('en', { numeric: 'auto' })
  .format(-1, 'day');  // "yesterday"

RTL Support

/* Use logical properties */
.container {
  margin-inline-start: 1rem;  /* margin-left in LTR, margin-right in RTL */
  padding-inline-end: 1rem;
}

/* Direction attribute */
html[dir="rtl"] .icon {
  transform: scaleX(-1);
}

Additional Frameworks

See references/frameworks.md for:

React-Intl (Format.js) complete implementation
Python gettext with Flask/Babel
RTL language support patterns
ICU Message Format examples

Best Practices

Extract all user-facing strings
Use ICU message format for complex translations
Test with pseudo-localization
Support RTL from the start
Never concatenate translated strings
Use professional translators for production

Other skills for the same job

different authors, same section of the catalogue

Changelog Generator

by frostant

×9

Automatically creates user-facing changelogs from git commits by analyzing commit history, categorizing changes, and transforming technical commits into clear, customer-friendly release notes. Turns hours of manual changelog writing into minutes of automated generation.

Use when the user asks to run Codex CLI (codex exec, codex resume) or references OpenAI Codex for code analysis, refactoring, or automated editing. Uses GPT-5.2 by default for state-of-the-art software engineering.

2k tokens

Memory Safety Patterns

by ComeOnOliver

×2

Implement memory-safe programming with RAII, ownership, smart pointers, and resource management across Rust, C++, and C. Use when writing safe systems code, managing resources, or preventing memory bugs.

Python/HTSlib workflows for genomic files. Use when reading, querying, filtering, or writing SAM/BAM/CRAM, VCF/BCF, FASTA/FASTQ, or tabix data with pysam, including pileup, coverage, indexing, and CRAM references.

34k tokens scripts

Scientific Critical Thinking

by K-Dense-AI

×1

Evaluate scientific claims and evidence quality. Use for assessing experimental design validity, identifying biases and confounders, applying evidence grading frameworks (GRADE, Cochrane Risk of Bias), or teaching critical analysis. Best for understanding evidence quality, identifying flaws. For formal peer review writing use peer-review.

Use when a user asks to debug or fix failing GitHub PR checks that run in GitHub Actions; use `gh` to inspect checks and logs, summarize failure context, draft a fix plan, and implement only after explicit approval. Treat external providers (for example Buildkite) as out of scope and report only the details URL.

8k tokens scripts

Declarative Agent Developer

by microsoft

vendor ×1

> Create, build, deploy, and localize declarative agents for M365 Copilot and Teams. USE THIS SKILL for ANY task involving a declarative agent — including localization, scaffolding, editing manifests, adding capabilities, and deploying. Localization requires tokenized manifests and language files that only this skill knows how to produce. "scaffold an agent", "new agent project", "add a capability", "add a plugin", "configure my agent", "deploy my agent", "fix my agent manifest", "edit my agent", "localize my agent", "add localization", "translate my agent", "multi-language agent", "add an API plugin", "add an MCP plugin", "add OAuth to my plugin", "review instructions", "improve instructions", "fix my instructions"

Documentation generation workflow covering API docs, architecture docs, README files, code comments, and technical writing.

1k tokens

How to use it

Copy the folder

Take secondsky/internationalization-i18n from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.