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 tommymorgan/claude-plugins --skill five-whys-methodologygit clone --depth 1 https://github.com/tommymorgan/claude-pluginsWrote 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/tommymorgan/claude-plugins/five-whys-methodology)<a href="https://agentmods.dev/skills/tommymorgan/claude-plugins/five-whys-methodology"><img src="https://agentmods.dev/badge/skills/tommymorgan/claude-plugins/five-whys-methodology.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 5.1 | $0.00075 | $0.01822 |
| Opus 5 | $0.00037 | $0.00911 |
| Sonnet 5 | $0.00015 | $0.00364 |
| Haiku 4.5 | $0.00007 | $0.00182 |
Grade A, and why
Five Whys 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 8d 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.
How it starts
The opening of the file, as written. The whole thing — 259 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Five Whys Root Cause Analysis
Purpose
This skill enforces systematic root cause identification before solution attempts. Apply the five whys methodology to prevent speculation-driven debugging that wastes effort, creates harmful changes, and results in never-ending fix loops.
Core Problem
Claude Code's default behavior when encountering problems:
- Observe symptom
- Speculate about cause
- Implement speculative fix
- Fix doesn't work or creates new problems
- Repeat indefinitely
Result: Wasted effort, potentially harmful changes, user frustration.
Five Whys Methodology
The Process
Start with the observed symptom and iteratively ask "why?" until reaching an actionable root cause.
Example progression:
- Symptom: Login returns 500 error
- Why #1: Why does login return 500? → Database connection timeout
- Why #2: Why does database timeout? → Connection pool exhausted
- Why #3: Why is pool exhausted? → Connections not being released
- Why #4: Why aren't connections released? → Missing connection.release() call in session handler
Root cause identified: Missing connection.release() call - this is actionable.
Iteration Guidelines
Continue asking "why" until:
- The cause is actionable (can be fixed with code/config changes)
- The cause directly explains the observed symptom
- Next "why" would be outside our control (external system, architectural decision)
Don't stop at:
- Symptom restatements ("it's broken because it doesn't work")
- Vague causes ("there's a configuration issue")
- First plausible explanation without verification
- Standard iteration counts (five is just a name - continue until root cause found)
Evidence-Based Investigation
For each "why", gather evidence:
-
Read relevant code:
- Files mentioned in error messages
- Call stack locations
- Related modules and dependencies
-
Examine outputs:
- Error messages and stack traces
- Log files
- Console output
- Test results
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.
- 8d ago First seen · 259 lines · 75 tokens per session scan A 0f69f92f9612
Five Whys Root Cause Analysis is a skill published in the GitHub repository tommymorgan/claude-plugins (4 stars, last pushed 1mo ago), licensed MIT. It adds 75 tokens to every session and 1,822 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 2026-08-31.
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