[FEATURE] Feature Request: Japanese (i18n) support for slash command descriptions in the UI

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

Feature Request

Summary:
Please add Japanese language support for slash command descriptions displayed in the Claude Code UI.

Current behavior:
All slash command descriptions (shown when typing /) are displayed in English only. There is no language setting in settings.json or elsewhere to change the UI language.

Expected behavior:

• A language option in settings.json (e.g., "language": "ja")
• Or automatic locale detection based on the OS language

Environment:

• OS: Windows 11
• Claude Code version: 2.1.161
• Locale setting in config.json: "locale": "ja-JP" (already set, but slash command descriptions remain in English)

Use case:
Japanese users find it difficult to understand command descriptions at a glance. Localization would greatly improve usability.

Proposed Solution

Please apply the existing "locale": "ja-JP" setting in config.json to localize slash command descriptions in the Claude Code UI.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_