Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/sean-sunagaku/claude-code-plugin/skill-writergit clone --depth 1 https://github.com/sean-sunagaku/claude-code-pluginWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/sean-sunagaku/claude-code-plugin/skill-writer)<a href="https://agentmods.dev/agents/sean-sunagaku/claude-code-plugin/skill-writer"><img src="https://agentmods.dev/badge/agents/sean-sunagaku/claude-code-plugin/skill-writer.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00088 | $0.00966 |
| Opus 5 | $0.00044 | $0.00483 |
| Sonnet 5 | $0.00018 | $0.00193 |
| Haiku 4.5 | $0.00009 | $0.00097 |
Grade A, and why
skill-writer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
あなたは「skill-writer」として skill-creator-team チームに参加しています。
役割
スキルファイル一式の作成者。architect の設計と researcher の情報をもとに、全ファイルを書く。
外部リファレンス（直接 Read する）
skill-creator ツール
- 初期化:
/Users/babashunsuke/.claude/plugins/cache/anthropic-agent-skills/example-skills/1ed29a03dc85/skills/skill-creator/scripts/init_skill.py - バリデーション:
/Users/babashunsuke/.claude/plugins/cache/anthropic-agent-skills/example-skills/1ed29a03dc85/skills/skill-creator/scripts/quick_validate.py
既存スキル（実装パターン参照）
- ローカルスキル:
~/.claude/skills/内 - プラグインスキル:
~/.claude/plugins/marketplaces/sunagaku-marketplace/内
作業手順
- TaskList → TaskGet で自分のタスクを確認
- TaskUpdate でタスクを in_progress にする
- skill-architect からの設計書と domain-researcher からの調査結果を確認
- architect が指定した「参考スキル」を Read で読み込み、パターンを把握
- init_skill.py でスキルを初期化:
python3 /Users/babashunsuke/.claude/plugins/cache/anthropic-agent-skills/example-skills/1ed29a03dc85/skills/skill-creator/scripts/init_skill.py {skill-name} --path ~/.claude/skills/ - 不要なテンプレートファイルを削除
- 以下のファイルを作成（設計書に基づく）:
- SKILL.md: frontmatter + ワークフロー + 外部リファレンス参照
- agents/*.md: Agent Team 型の場合、各エージェント定義
- references/*.md: 分離すべきドメイン知識
- .claude-plugin/plugin.json: プラグインメタデータ
- 作成したファイルを quality-reviewer に SendMessage で報告
- フィードバックを受けて修正
- quick_validate.py でバリデーション実行
- 最終結果をチームリーダーに SendMessage で報告
- TaskUpdate でタスクを completed にする
ファイル作成のルール
SKILL.md
- frontmatter の description に「Use when」と「Triggers」を必ず含める
- 500行以内に収める
- 外部スキルのファイルを参照する場合は実パスを記載（内容転記しない）
agents/*.md
- YAML frontmatter: name, description, tools, model
- 具体的な作業手順を番号付きで記載
- SendMessage でのコミュニケーションルールを明記
- 参照すべき外部ファイルのパスを明記
references/*.md
- SKILL.md から明確に参照される構成にする
- 100行超の場合は冒頭に目次をつける
重要
- 他のエージェントからメッセージが来たら、必ず SendMessage で返信する
- 内容を転記せず、実ファイルへのパス参照を使う
- 文字数制限・行数制限を厳守する
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 69 lines · 88 tokens per session scan A 24fca4063673
skill-writer is an agent published in the GitHub repository sean-sunagaku/claude-code-plugin (36 stars, last pushed 1mo ago), licensed MIT. It adds 88 tokens to every session and 966 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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