silent-failure-hunter

silent-failure-hunter is a skill for Claude Code, Codex from kyto64/codex-pr-review-toolkit-minimal. It costs 25 tokens per session (1,115 once invoked), scanned A, original, Apache-2.0.

A code-review guide for finding failures that are hidden, poorly reported, or replaced by unsafe fallback behavior. A fallback is an alternative result used when the normal operation fails.

In plain words
What is it for?
Use it when reviewing error handling, retries, default values, optional access, exception handling, or fallback code.
Why use it?
It helps ensure errors are logged with useful context, explained to users, and passed on when they should not be hidden.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions AGENTS.md.

Good fit Use it when reviewing error handling, retries, default values, optional access, exception handling, or fallback code.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter
Install

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.

Any agent
npx skills add kyto64/codex-pr-review-toolkit-minimal --skill silent-failure-hunter
Clone the repo
git clone --depth 1 https://github.com/kyto64/codex-pr-review-toolkit-minimal

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 silent-failure-hunter

README.md
[![agentmods](https://agentmods.dev/badge/skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter/github.svg)](https://agentmods.dev/skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter)
Your own site
<a href="https://agentmods.dev/skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter"><img src="https://agentmods.dev/badge/skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter/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 silent-failure-hunter

Your own site · 80×15
<a href="https://agentmods.dev/skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter"><img src="https://agentmods.dev/badge/skills/kyto64/codex-pr-review-toolkit-minimal/silent-failure-hunter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,115 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 $0.00025 $0.01115
Opus 5 $0.00013 $0.00558
Sonnet 5 $0.00005 $0.00223
Haiku 4.5 $0.00003 $0.00112

Measured 12d ago against content hash bb08f68a6385, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

silent-failure-hunter 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 12d 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.

docs/ja/skills/silent-failure-hunter/SKILL.md · 86 lines

What it actually says

Silent Failure Hunter

サイレント障害、不十分なエラー処理、危険なフォールバックを検出する。pr-reviewsilent-failure 観点として使う。

原則

  1. サイレント障害は許容しない: ログもユーザー通知もなく発生するエラーは欠陥
  2. ユーザーには actionable なフィードバック: 何が起きたか・どうすればよいかを伝える
  3. フォールバックは明示的かつ正当な理由付きで: ユーザーが気づかない代替動作は問題を隠す
  4. catch は具体的に: 広い例外捕捉は無関係なエラーを隠しデバッグを不可能にする
  5. mock/stub は本番コードに置かない: 本番でのフォールバック先が fake なら設計問題

レビュー手順

1. エラー処理箇所を列挙する

  • try-catch(言語により try-except / Result 型 / エラーコールバック)
  • エラー状態を扱う条件分岐
  • 失敗時のフォールバックロジック・デフォルト値
  • ログだけ出して処理続行する箇所
  • 失敗を隠しうる optional chaining (?.) / null 合体

2. 各箇所を4軸で精査する

ログ品質

  • 適切な重大度でログされているか
  • 失敗した操作・関連ID・状態などコンテキストが十分か
  • 6ヶ月後にこのログでデバッグできるか

ユーザーへの伝達

  • 何が失敗したか、ユーザーが次に何をすべきかが伝わるか
  • メッセージが汎用的すぎて他のエラーと区別できない状態になっていないか

catch の特異性

  • 想定したエラー型だけを捕捉しているか
  • この catch が隠しうる想定外エラーの型を列挙する(本 Skill の核心)
  • 複数の catch に分けるべきか

フォールバックと伝播

  • フォールバックは仕様で要求されたものか、それとも問題の隠蔽か
  • 上位ハンドラへ伝播すべきエラーを握りつぶしていないか
  • ここで catch することでクリーンアップやリソース解放を妨げないか

3. 隠蔽パターンを探す

  • 空の catch(常に欠陥)
  • ログのみで続行
  • エラー時に null / デフォルト値を無ログで返す
  • リトライ回数を使い切ってもユーザーに通知しない
  • 理由の説明なく複数手段を順に試すフォールバックチェーン
  • 本番コードでの mock/stub フォールバック

重要度の目安

状況 重要度
空 catch、障害の完全握りつぶし、本番での mock フォールバック P0
広い catch、正当化されないフォールバック、誤解を招くメッセージ P1
ログコンテキスト不足、メッセージが具体性に欠ける P2

出力

### P1: Silent failure in error handling
- File: `src/foo.ts`
- Lines: 42-49
- Category: silent-failure
- Problem: [何が握りつぶされているか]
- Hidden errors: [この catch / フォールバックが隠しうるエラー型]
- Impact: [デバッグ・ユーザー体験への影響]
- Suggested fix: [ログ・伝播・メッセージの具体案。可能なら修正後コード例]

ルール

  • DO: 各 catch / フォールバックについて、隠されうるエラー型を具体的に列挙する
  • DO: ユーザー向けに actionable なメッセージを推奨する
  • DO: 適切に処理できているエラー処理は短く肯定的に言及してよい
  • DO NOT: プロジェクトの正当なエラー処理パターン(AGENTS.md 等の規約)を誤検知する
  • DO NOT: テストコードのモックを本番問題として報告する
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. 12d ago First seen · 86 lines · 25 tokens per session scan A bb08f68a6385

Subscribe to this mod's changes

silent-failure-hunter is a skill published in the GitHub repository kyto64/codex-pr-review-toolkit-minimal (1 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 25 tokens to every session and 1,115 once invoked, about $0.0001 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 2026-08-31.

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