Investigates and repairs software defects using evidence-based root cause analysis and minimal patches.

Install

mkdir -p .claude/skills/bug-hunter && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/15079" && unzip -o skill.zip -d .claude/skills/bug-hunter && rm skill.zip

Installs to .claude/skills/bug-hunter

Activation

This is the description your AI agent reads to decide when to run this skill — the better it matches your request, the more reliably it fires.

Investigate and fix software defects with reproducible evidence and minimal-risk patches. Use for crashes, regressions, flaky behavior, and logic faults in frontend or backend. Keywords: debug, root cause, repro, regression.
224 chars✓ has a “when” trigger
Advanced

Key capabilities

  • Define the failure contract including expected vs. actual behavior
  • Reproduce the bug minimally or list variability factors
  • Trace code paths and state transitions around the fault boundary
  • Build and eliminate hypotheses using direct evidence
  • Implement the smallest durable fix at the causal layer
  • Add or update regression tests for the failed behavior

How it works

The skill systematically investigates software defects by defining the failure, reproducing the issue, tracing code paths, and building hypotheses. It then implements a minimal fix and ensures regression protection through targeted tests.

Inputs & outputs

You give it
Observed behavior, expected behavior, reproduction steps, and recent changes
You get back
Reproduction summary, confirmed root cause, applied/proposed fix, validation evidence, and a regression-prevention checklist

When to use bug-hunter

  • Fixing a production crash
  • Investigating flaky tests
  • Patching a regression after deployment

About this skill

Bug Hunter

Mission

Find the true fault, apply the smallest durable fix, and prove it will not regress.

Use This Skill When

  • A feature is broken and the failure reason is unclear
  • A regression appeared after recent changes
  • The same issue is hard to reproduce consistently
  • You need a minimal fix with regression protection

Non-Goals

  • Do not perform broad refactors while debugging.
  • Do not mark root cause as confirmed without evidence.

Required Inputs

  • Expected behavior
  • Actual behavior
  • Reproduction steps and environment details
  • Logs, stack traces, or failing test output if available

Procedure

  1. Define failure contract: expected vs actual, scope, impact.
  2. Reproduce minimally; if not reproducible, list variability factors and rank likely causes.
  3. Trace code path and state transitions around the fault boundary.
  4. Build 1-3 hypotheses and eliminate alternatives using direct evidence.
  5. Implement smallest durable fix at the causal layer.
  6. Add or update regression test for the failed behavior.
  7. Re-run targeted validations and nearby critical flows.

Edge Cases To Check

  • Null, empty, malformed, and extreme input values
  • Race conditions and async ordering
  • Permission and role-dependent paths
  • Retry/timeout behavior and partial failures
  • Environment-specific config drift

Exit Criteria

  • Reproduction is documented or uncertainty is explicitly bounded.
  • Root cause is evidenced and fix is applied/proposed.
  • Validation evidence is provided for fix and adjacent flow safety.

Output Format

  1. Reproduction summary
  2. Confirmed root cause
  3. Applied or proposed fix
  4. Validation evidence
  5. Regression-prevention checklist

When not to use it

  • When performing broad refactors while debugging
  • When marking root cause as confirmed without evidence
  • When the goal is not to find the true fault and apply a minimal fix

Limitations

  • Does not perform broad refactors during debugging.
  • Requires evidence to confirm the root cause.
  • The fix must be the smallest durable change at the causal layer.

How it compares

This skill provides a structured, evidence-based approach to bug fixing, focusing on minimal, durable changes and regression prevention, which is more rigorous than ad-hoc debugging.

Compared to similar skills

bug-hunter side by side with the closest alternatives in the catalog.

SkillInstallsUpdatedSafetyDifficulty
bug-hunter (this skill)04moNo flagsAdvanced
python-testing-patterns772moReviewIntermediate
chrome-devtools417moReviewIntermediate
bats97moReviewIntermediate

Try saying

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