common-debugging

common-debugging is a skill for Claude Code, Codex from HoangNguyen0403/agent-skills-standard. It costs 29 tokens per session (476 once invoked), scanned A, original, MIT.

A systematic debugging guide based on the scientific method: observe the evidence, reproduce the failure, test one explanation, fix the proven cause, and verify the result.

In plain words
What is it for?
It helps investigate crashes, exceptions, unexpected behavior, production-only failures, and regression risks.
Why use it?
It reduces guesswork and discourages changing code before understanding what actually caused the failure.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

Good fit It helps investigate crashes, exceptions, unexpected behavior, production-only failures, and regression risks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hoangnguyen0403/agent-skills-standard/common-debugging
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 HoangNguyen0403/agent-skills-standard --skill common-debugging
Clone the repo
git clone --depth 1 https://github.com/HoangNguyen0403/agent-skills-standard

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 common-debugging

README.md
[![agentmods](https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/common-debugging/github.svg)](https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/common-debugging)
Your own site
<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/common-debugging"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/common-debugging/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 common-debugging

Your own site · 80×15
<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/common-debugging"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/common-debugging.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 476 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00029 $0.00476
Opus 5 $0.00015 $0.00238
Sonnet 5 $0.00006 $0.00095
Haiku 4.5 $0.00003 $0.00048

Measured 12d ago against content hash 9701906d15c3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

common-debugging 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.

.agents/skills/common/common-debugging/SKILL.md · 61 lines

What it actually says

Debugging Expert

Priority: P1 (HIGH)

Root-Cause Protocol

  1. OBSERVE: Gather error, logs, repro steps, recent diffs.
  2. REPRODUCE: Make the failure happen on demand or gather more evidence.
  3. HYPOTHESIZE: State one hypothesis in plain language.
  4. EXPERIMENT: Change one variable to prove or kill the theory.
  5. FIX: Touch code only after root cause proven.
  6. VERIFY: Re-run the failing case and regression checks.

Red Flags

  • Stop if you are changing code before repro: You are guessing.
  • Stop if fix #2 starts before understanding fix #1: Re-open root cause.
  • Stop if "quick patch for now" appears: Symptom masking starts there.

Rationalization Prevention

  • "The bug is obvious": Obvious bugs still need evidence.
  • "I already tried a few things": That means you need structure.
  • "It only fails in prod": Gather prod evidence, do not invent local myths.
  • Minimal repro first: A minimal reproduction beats more random fixes.

Anti-Patterns

  • No shotgun debugging: Prove root cause before changing code.
  • No debug prints in production: Remove all print/console.log before commit.
  • No symptom masking: Fix root cause; never swallow errors without handling.

References

Incident pressure checklist

  • For production incidents, reproduce with a production-like replay and state one hypothesis before changing code; stop symptom patches until the root cause is proven.

Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:

  • hypothesis

  • one hypothesis

  • stop

  • Additional task-grounded exact anchors: minimal

Files

What ships with it

1 file 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. 12d ago First seen · 61 lines · 29 tokens per session scan A 9701906d15c3

Subscribe to this mod's changes

common-debugging is a skill published in the GitHub repository HoangNguyen0403/agent-skills-standard (565 stars, last pushed 2d ago), licensed MIT. It adds 29 tokens to every session and 476 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 2026-08-30.

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