Borrowing it
Nothing to install: this file belongs to YankielDBC2/codex-skills-library. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/YankielDBC2/codex-skills-library/main/.agents/skills/debug-root-cause/SKILL.mdgit clone --depth 1 https://github.com/YankielDBC2/codex-skills-libraryWrote 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/yankieldbc2/codex-skills-library/debug-root-cause)<a href="https://agentmods.dev/skills/yankieldbc2/codex-skills-library/debug-root-cause"><img src="https://agentmods.dev/badge/skills/yankieldbc2/codex-skills-library/debug-root-cause/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/yankieldbc2/codex-skills-library/debug-root-cause"><img src="https://agentmods.dev/badge/skills/yankieldbc2/codex-skills-library/debug-root-cause.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 | $0.00029 | $0.00309 |
| Opus 5.5 | $0.00012 | $0.00124 |
| Sonnet 5.5 | $0.00006 | $0.00062 |
| Haiku 4.5 | $0.00003 | $0.00031 |
Grade A, and why
debug-root-cause 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 2mo 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
Debug Root Cause
Goal
Find the smallest proven cause of a bug before editing code.
When to use
Use when the user reports broken behavior, an error, regression, failing test, crash, incorrect output, or unexpected state.
When not to use
Do not use when the fix is already known and the task is only implementation.
Inputs
Collect the error message, reproduction steps, failing test, logs, relevant files, recent changes, and expected behavior.
Workflow
- Reproduce the failure or identify the exact failing path.
- Read the smallest relevant files first.
- Separate symptoms from possible causes.
- Form one or more hypotheses.
- Test each hypothesis using code, logs, tests, or runtime evidence.
- Patch the root cause, not the visible symptom.
- Add a regression test when the project has a test structure.
- Re-run the failing scenario.
Quality bar
A good debugging result explains why the bug happened, why the fix addresses the cause, and what validation proves it.
Validation
Run the failing test or reproduction first, then run the smallest broader validation suite that makes sense.
Final response
Report root cause, changed files, validation commands, and any remaining uncertainty.
What ships with it
4 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.
- 2mo ago First seen · 49 lines · 29 tokens per session scan A 85e6bef8e690
debug-root-cause is a skill published in the GitHub repository YankielDBC2/codex-skills-library (13 stars, last pushed 3mo ago), licensed MIT. It adds 29 tokens to every session and 309 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 2026-08-31.
debug-root-cause compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| debug-root-causeYankielDBC2/codex-skills-library | Skill | 13 | 3mo ago | MIT | A | 29 | Codex |
| systematic-debuggingopen-metadata/OpenMetadata | Skill | 16k | yesterday | Apache-2.0 | A | 37 | Claude Code |
| log-error-digestzebbern/claude-code-guide | Skill | 4.7k | 3d ago | MIT | A | 71 | Claude Code, Codex |
| cwv-optimizeradobe/skills | Skill | 319 | yesterday | Apache-2.0 | A | 112 | Claude Code |
| ci-fixersipyourdrink-ltd/bernstein | Skill | 1.2k | yesterday | Apache-2.0 | A | 15 | Claude Code, Codex |
| incident-response-incident-responsermyndharis/antigravity-skills | Skill | 1.9k | 23d ago | MIT | A | 36 | Claude Code |
| triaging-web-analytics-supportPostHog/posthog | Skill | 41k | yesterday | none | A | 151 | Claude Code, Codex |