Feature Request: Localization / i18n support for built-in skill and command descriptions

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When pressing / in Claude Code, the command/skill picker shows descriptions for all built-in skills (e.g. anthropic-skills:docx, anthropic-skills:pdf, plugin skills like codex:*, cc-gemini-plugin:*). These descriptions are hardcoded in English and cannot be changed by the user.

Users who work in non-English languages (e.g. German, French, Spanish) have no way to get these descriptions in their native language. Custom commands in ~/.claude/commands/ do support localized descriptions via frontmatter, but built-in and plugin skills do not.

Proposed Solution

Two complementary approaches:

1. i18n / locale support: Claude Code reads the system locale (LANG env var or OS setting) and loads skill/command descriptions from locale-specific files (e.g. skill.de.md, skill.fr.md). Falls back to English if no translation exists.
2. User override via settings: Allow a descriptionLanguage setting in ~/.claude/settings.json that lets users specify their preferred language for skill descriptions. Plugin authors can ship translation files alongside their SKILL.md.

Either approach would allow non-English speakers to use the / command picker comfortably in their native language.

Alternative Solutions

Manually editing ~/.claude/commands/ descriptions works for custom commands, but not for built-in anthropic-skills:* or plugin skills — those files are either bundled in the binary or overwritten on plugin updates.

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

A German-speaking developer presses / to find the right skill for a task. All descriptions are in English, making it hard to quickly identify what each skill does. With locale support, the same menu would show German descriptions, e.g. anthropic-skills:docx showing "Word-Dokumente erstellen, lesen und bearbeiten" instead of the English text.

Additional Context

_No response_