Feature request: i18n / localization for CLI UI strings

Summary

The Claude Code CLI UI is currently English-only. While the assistant can respond in any language, the surrounding harness chrome stays in English, which feels jarring for non-English-speaking users.

Examples of UI strings that aren''t localized

• Status spinner with whimsical words: ✻ Sautéed for 19s · 1 shell still running, Pondering..., Cooking..., etc.
• Permission prompts ("Allow Claude to run this command?")
• Error messages from the harness
• Slash command help text
• Onboarding / first-run messages

Proposed solution

• Add a locale setting, e.g. CLAUDE_LANG=ru env var or "locale": "ru" in ~/.claude/settings.json
• Auto-detect from LANG / system locale as default
• Start with translation files for the most user-visible strings (status indicator, permission prompts, errors)
• Community-driven translations (similar to how VS Code handles language packs)

Why it matters

Russian-speaking users (and presumably users of other languages) configure Claude to respond in their language, but the CLI chrome around responses stays English. A consistent localized experience would lower the friction for international users.

Environment

• Claude Code CLI on Windows 11 (Git Bash)
• Version: latest as of 2026-05-01