codex-harness: Skill for Claude Code

.codex/skills/auth/SKILL.md

auth is a skill for Claude Code, Codex from Chachamaru127/codex-harness. It costs 56 tokens per session (880 once invoked), scanned A, original, MIT.

A skill for adding user login, identity checks, and payments with Clerk, Supabase Auth, and Stripe.

In plain words
What is it for?
Use it when implementing authentication, subscriptions, or Stripe payments, including secure session handling and payment-flow checks.
Why use it?
It guides security checks for sensitive areas such as password storage, sessions, payment data, webhooks, and error messages.

Skill for Claude CodeCodex

Written for Claude Code and Codex: allowed-tools in frontmatter, but also installed under .codex/.

This is Chachamaru127/codex-harness's own configuration. It tells Claude Code and Codex how to work on codex-harness itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything codex-harness configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Chachamaru127/codex-harness. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Chachamaru127/codex-harness/main/.codex/skills/auth/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Chachamaru127/codex-harness

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for auth

README.md
[![agentmods](https://agentmods.dev/badge/skills/chachamaru127/codex-harness/auth/github.svg)](https://agentmods.dev/skills/chachamaru127/codex-harness/auth)
Your own site
<a href="https://agentmods.dev/skills/chachamaru127/codex-harness/auth"><img src="https://agentmods.dev/badge/skills/chachamaru127/codex-harness/auth/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for auth

Your own site · 80×15
<a href="https://agentmods.dev/skills/chachamaru127/codex-harness/auth"><img src="https://agentmods.dev/badge/skills/chachamaru127/codex-harness/auth.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 880 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00056 $0.00880
Opus 5.5 $0.00022 $0.00352
Sonnet 5.5 $0.00011 $0.00176
Haiku 4.5 $0.00006 $0.00088

Measured 1mo ago against content hash 23baefa8d531, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

auth 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 1mo 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.

.codex/skills/auth/SKILL.md · 84 lines

What it actually says

Auth Skills

認証と決済機能の実装を担当するスキル群です。

機能詳細

機能 詳細
認証機能 See references/authentication.md
決済機能 See references/payments.md

実行手順

  1. 品質判定ゲート(Step 0)
  2. ユーザーのリクエストを分類(認証 or 決済)
  3. 上記の「機能詳細」から適切な参照ファイルを読む
  4. その内容に従って実装

Step 0: 品質判定ゲート(セキュリティチェックリスト)

認証・決済機能は常にセキュリティリスクが高いため、作業開始前に必ず以下を表示:

🔐 セキュリティチェックリスト

この作業はセキュリティ上重要です。以下を確認してください:

### 認証関連
- [ ] パスワードはハッシュ化(bcrypt/argon2)
- [ ] セッション管理は安全か(HTTPOnly Cookie)
- [ ] CSRF 対策は実装されているか
- [ ] レート制限(ブルートフォース対策)

### 決済関連
- [ ] 機密情報(カード番号等)をサーバーに保存しない
- [ ] Stripe/決済プロバイダの SDK を正しく使用
- [ ] Webhook の署名検証
- [ ] 金額改ざん防止(サーバー側で金額を確定)

### 共通
- [ ] エラーメッセージが詳細すぎないか(情報漏洩防止)
- [ ] ログに機密情報を出力していないか

セキュリティ重要度表示

⚠️ 注意レベル: 🔴 高

この機能は以下のリスクがあります:
- 認証情報の漏洩
- 不正アクセス
- 決済の不正操作

専門家によるレビューを推奨します。

VibeCoder 向け

🔐 安全にログイン・決済機能を作るために

1. **パスワードは「ハッシュ化」する**
   - 元のパスワードを復元できない形で保存
   - 万が一データが漏れても安全

2. **カード情報はサーバーに保存しない**
   - Stripe などの専用サービスに任せる
   - 自分のサーバーには一切保存しない

3. **エラーメッセージは曖昧に**
   - 「パスワードが違います」ではなく「認証に失敗しました」
   - 悪意ある人にヒントを与えない
Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

  1. 1mo ago First seen · 84 lines · 56 tokens per session scan A 23baefa8d531

Subscribe to this mod's changes

auth is a skill published in the GitHub repository Chachamaru127/codex-harness (2 stars, last pushed 8mo ago), licensed MIT. It adds 56 tokens to every session and 880 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-31.

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