English Coding Coach

A skill that helps Japanese developers build English skills naturally through everyday coding. The agent always responds in English with inline vocabulary support — no English lessons, just real coding assistance that happens to teach you English along the way.

This skill follows the open Agent Skills standard.

Skills.sh

Who is this for?

• Japanese developers who want to get comfortable coding in English
• Developers who struggle with English documentation and technical writing
• Anyone who wants to improve their English naturally through daily development work

Compatible Agents

• Claude Code (Plugin or manual install)
• OpenAI Codex CLI (via Skills CLI)
• Cursor (via Skills CLI)
• Any agent supporting the Agent Skills format

Features

Feature	Description
Inline vocabulary annotations	difficult-word (simpler synonym / 日本語) — difficult words get English synonym + Japanese translation
Bold main verbs	Main verbs are bolded to make sentence structure easier to read
One sentence per line	Each sentence gets its own line for easier reading
jp: summary	Brief Japanese summary of the response content at the end

Examples

1. Bug fix — Asking about the cause of a bug

You: この関数がnullを返すんだけど原因わかる？

Claude Code:

The function returns null because the conditional check on line 12 doesn't account for (fails to handle / 考慮していない) empty arrays. When items.length is zero, the early return triggers before the main logic executes.

if (!items || items.length === 0) {
  return null; // ← this is the cause
}

You should replace this with a fallback (default value / デフォルト値) that returns an empty result instead of null.

---

jp: items が空配列のとき早期リターンで null を返している。空の結果を返すように修正すべき。

2. Code review — Asking for improvements

You: このAPIのエラーハンドリング、もっと良くできない？

Claude Code:

The current error handling catches all exceptions with a generic (general-purpose / 汎用的な) catch block. This obscures (hides / 隠す) the root cause and makes debugging harder.

I'd suggest we distinguish (separate / 区別する) between client errors and server errors:

try {
  const response = await fetch(url);
  if (!response.ok) {
    throw new HttpError(response.status, response.statusText);
  }
  return await response.json();
} catch (error) {
  if (error instanceof HttpError) {
    logger.warn(`Client error: ${error.status}`);
  } else {
    logger.error('Unexpected failure', error);
  }
  throw error;
}

This provides better observability (ability to monitor / 監視のしやすさ) and helps you pinpoint (identify exactly / 正確に特定する) issues in production.

---

jp: 汎用catchを廃止し、クライアントエラーとサーバーエラーを分けてログ出力。本番でのデバッグが容易になる。

3. New feature — Asking about implementation approach

You: ページネーション実装したいんだけど、cursor方式とoffset方式どっちがいい？

Claude Code:

It depends on your use case.

Offset-based pagination is straightforward (simple / シンプル) to implement, but it suffers from (has problems with / 問題がある) data inconsistency when rows are inserted or deleted between requests.

Cursor-based pagination eliminates (removes completely / 完全に解消する) that problem because each page is anchored to a specific record, not a numeric position.

For your case — a feed with frequently (often / 頻繁に) updated content — cursor-based is the better fit. The trade-off (compromise / トレードオフ) is that users can't jump to an arbitrary (any chosen / 任意の) page number.

---

jp: 更新頻度が高いフィードにはcursor方式が適切。offset方式はデータ追加削除時にずれが生じる。ただしページ番号ジャンプはできない。

Installation

Option 1: Claude Code Plugin (recommended)

Run these commands inside Claude Code (/ commands are Claude Code built-in):

# Step 1: Add the marketplace
/plugin marketplace add enumura1/english-coding-coach

# Step 2: Install the plugin
/plugin install english-coding-coach

Option 2: Skills CLI (works with Claude Code, Codex, Cursor, etc.)

Requires Node.js installed.

npx skills add enumura1/english-coding-coach

Option 3: Manual copy

Copy skills/english-coaching/ folder to your project's .claude/skills/ directory.

How it works

• You write in Japanese or English — either is fine
• Claude Code always responds in English with inline vocabulary support
• No setup, no commands — just start coding

Design principles

• Coding first — English learning is a side effect, not the main purpose
• No over-annotation — annotations stay under ~10% of non-code text
• Code stays clean — no annotations inside code blocks
• No escape hatch — jp: summarizes content but doesn't translate everything, so you still engage with the English text

Skill Structure

english-coding-coach/
├── .claude-plugin/
│   └── plugin.json              # Plugin manifest
├── skills/
│   └── english-coaching/
│       ├── SKILL.md             # Skill instructions (loaded when activated)
│       └── references/
│           └── vocabulary.md    # Word lists (loaded on demand)
├── CLAUDE.md                    # Project instructions (for this repo's own dev)
├── marketplace.json             # Self-hosted marketplace definition
├── LICENSE                      # MIT
└── README.md

Requirements

• Claude Code or any compatible agent installed
• No additional dependencies

License

MIT