# Common Debugging

> Troubleshoot systematically using the Scientific Method. Use when debugging crashes, tracing errors, diagnosing unexpected behavior, or investigating exceptions.

- Skill: `hoangnguyen0403/common-debugging` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add hoangnguyen0403/common-debugging`
- Raw SKILL.md: https://api.skillmd.com/api/skills/hoangnguyen0403/common-debugging/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: HoangNguyen0403 (https://skillmd.com/u/hoangnguyen0403)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/hoangnguyen0403/common-debugging

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# 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

- [Bug Report Template](references/bug-report-template.md)

## 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