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 skills add thkt/dotclaude --skill use-context-root-cause-analysisgit clone --depth 1 https://github.com/thkt/dotclaudeWrote 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/skills/thkt/dotclaude/use-context-root-cause-analysis)<a href="https://agentmods.dev/skills/thkt/dotclaude/use-context-root-cause-analysis"><img src="https://agentmods.dev/badge/skills/thkt/dotclaude/use-context-root-cause-analysis/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.
<a href="https://agentmods.dev/skills/thkt/dotclaude/use-context-root-cause-analysis"><img src="https://agentmods.dev/badge/skills/thkt/dotclaude/use-context-root-cause-analysis.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00020 | $0.00779 |
| Opus 5.5 | $0.00008 | $0.00312 |
| Sonnet 5.5 | $0.00004 | $0.00156 |
| Haiku 4.5 | $0.00002 | $0.00078 |
Grade A, and why
use-context-root-cause-analysis 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.
What it actually says
use-context-root-cause-analysis
原則
症状ではなく根本原因を修正する。対症療法は複雑性を増やし、根本原因の修正は再発を防ぐ。
手法
${CLAUDE_SKILL_DIR}/../../rules/core/OPERATION.md § Debug Investigation Protocol が正。fork 実行では常時ロードの rules が届かないので、手順をここに写す。
- 動く類似コードと壊れたコードを差分比較し、違いを列挙する
- 原因の仮説を 3 つ以上立てる。候補の出どころは ${CLAUDE_SKILL_DIR}/references/symptom-patterns.md
- 各仮説を検証で潰す。1 つに絞れないうちは結論を出さない
- 残った仮説が根本原因。「これを直せば症状が消えるか」で確かめる
| 落とし穴 | 扱い |
|---|---|
| 最初の仮説で止まる | 3 つ揃うまで検証を始めない |
| 仮説を検証せず消す | 消す根拠は実行結果か証拠。もっともらしさでは消さない |
| 抽象へ流れる | アクションが取れる高さで止める。設計論まで遡らない |
| 仮説が全部残る | 差分比較の粒度を上げ、違いを 1 つずつ切り分けて再度潰す |
Pattern の判定
Pattern は原因の深さでなく再発経路の有無で決まる。root cause と同じ形のコードが他にあるかを走査して分類する。
| 値 | 判定 |
|---|---|
| Isolated | 同じ形が他に無い |
| Recurring | 近くに同じ形がある |
| Systematic | 設計から生じ、同じ形が層をまたいで現れる |
出力フォーマット
利用側は Pattern で分岐する。/fix は defense-in-depth を適用するか /research へ委譲するかを決める。
| フィールド | 説明 |
|---|---|
| Symptom | ユーザーから見た失敗 |
| Root cause | 検証で残った仮説 |
| Pattern | Isolated / Recurring / Systematic |
参照ファイル
| 迷うこと | ファイル |
|---|---|
| 仮説をどう立てるか | ${CLAUDE_SKILL_DIR}/references/symptom-patterns.md |
| 消去がどう進むか | ${CLAUDE_SKILL_DIR}/references/hypothesis-examples.md |
What ships with it
2 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.
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.
- 1mo ago First seen · 58 lines · 20 tokens per session scan A 2d17d72c6aec
use-context-root-cause-analysis is a skill published in the GitHub repository thkt/dotclaude (12 stars, last pushed 25d ago), licensed MIT. It adds 20 tokens to every session and 779 once invoked, about $0.0001 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 2026-08-30.
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