Verification Report

The English locale should behave as a first-class locale for supported content and as unavailable for unsupported books.

Expected Behavior

• /en renders the English home page.
• /en lists only English-localized handbooks.
• /en/books/claude-code-advanced renders English content.
• /en/books/claude-code-command-master renders English content.
• /en/books/codex-advanced does not fall back to Korean content.
• The preview chapter API receives a locale parameter.
• Sitemap generation includes English URLs only for English pages.

Local Checks

Run the focused handbook checks after changing locale routing or content availability:

yarn workspace handbook typecheck
yarn workspace handbook lint
yarn workspace handbook build
yarn workspace handbook test:e2e

If an E2E test fails, inspect whether it is asserting Korean-only copy or a route that is now locale-specific.

Content Checks

• Every English page has English frontmatter.
• Internal links use /en/books/....
• Korean-only books are not registered in content/books/en/meta.json; translated books are.
• The home catalog uses localized availability from the MDX source.
• Language links appear only when the same page exists in more than one locale.
• Claude Code content uses the 2026-06-25 check baseline: v2.1.190 (latest) and v2.1.179 (stable) from npm dist-tags, plus the official changelog through v2.1.190.
• The v2.1.181~v2.1.190 refresh covers sandbox credentials, destructive-command sandbox auto-approval, Windows PowerShell sandbox fixes, MCP login/logout, MCP idle timeout, model restrictions, deprecated-model warnings, nested-agent/background stability, Korean paste handling, and non-interactive fallback fixes.
• The v2.1.170 content remains valid for Fable 5, Opus 4.8, current model aliases, Agent View, background sessions, dynamic workflows, and the command surface.
• Fable-specific details include 30-day data retention, ZDR unavailability, always-on adaptive thinking, DISABLE_PROMPT_CACHING_FABLE, classifier fallback, and availability fallback chains.
• Recent operating notes include /cd session relocation, --safe-mode, bundled skill/workflow disabling, self-hosted runner post-session hooks, and the v2.1.170 transcript persistence fix.

Source Baseline

• Claude Code Changelog: https://code.claude.com/docs/en/changelog
• Model configuration: https://code.claude.com/docs/en/model-config
• Commands: https://code.claude.com/docs/en/commands
• Agent View: https://code.claude.com/docs/en/agent-view
• Claude Fable 5 and Claude Mythos 5: https://platform.claude.com/docs/en/about-claude/models/introducing-claude-fable-5-and-claude-mythos-5
• Claude models overview: https://platform.claude.com/docs/en/about-claude/models/overview
• Opus 4.8 announcement: https://www.anthropic.com/news/claude-opus-4-8
• npm package: https://www.npmjs.com/package/@anthropic-ai/claude-code

Residual Risk

The English locale now has multiple localized handbooks. Shared pages such as About and Graph have English UI labels, but deeper editorial polish should be handled as a separate content pass.