Systematic Debugging

This is the "stop guessing and find the root cause" skill for when you're tempted to just try fixes until something works. It enforces a four phase process: investigate the root cause first (add logging at component boundaries, trace data flow, read error messages completely), analyze patterns by comparing against working code, form a single testable hypothesis, then implement one fix with a failing test. The iron law is no fixes without investigation, even when you're in a hurry or the solution seems obvious. What I appreciate is the "three failed fixes" rule that forces you to question whether the architecture itself is wrong rather than attempting fix number four. It's opinionated about the fact that systematic debugging is actually faster than thrashing, even under time pressure.

skills.sh installs: 382
GitHub stars: 33.2K
last updated: Aug 21, 2026

View on GitHub

Install

$ npx -y skills add davila7/claude-code-templates --skill systematic-debugging --agent claude-code

Installs into .claude/skills of the current project.

Files

Systematic Debugging

Guessing at fixes feels fast and is slow. Each guess that half-works hides the real cause a little deeper, and the third patch usually breaks something the first one touched. This skill makes you find out why before you change anything.

The Iron Law

NO FIXES WITHOUT ROOT CAUSE INVESTIGATION FIRST

If you have not finished Phase 1, you cannot propose a fix. Not a "quick one to try", not "while we investigate". Suggesting a fix in your reply counts as proposing one.

The process scales. For a simple bug the four phases take a minute: read the error, confirm the cause, write the failing check, fix it. You never skip them, you just move through them quickly.

When to use

Any technical problem: test failures, production bugs, unexpected behavior, performance regressions, build or CI failures, integration issues, flaky tests.

Use it especially when: