Code Review & Testing · IN-DEPTH PROFILE

Diagnosing Bugs Skill

Diagnosing Bugs is an evidence-first loop for difficult defects and performance regressions.

View listed source ↗Installation guide ↓
Best for

Engineers investigating hard-to-reproduce bugs

What you get

Build a deterministic reproducer + Bisect the cause

Main limitation

It requires a repeatable pass/fail signal; intermittent production-only failures may need observability or human evidence first.

First risk

Secrets captured in diagnostic evidence. Requests, traces, screenshots, and logs can contain tokens, credentials, personal data, or production payloads. Redact before capture, minimize retention, and restrict access to every diagnostic artifact.

EVIDENCE FRESHNESS

Three checks, kept separate

A recent source check is not a runtime test or security audit.

Upstream sourceChecked 2026-09-23

Pinned revision · c55ee460

Open pinned commit ↗
SkillSignal profileSource-grounded

Updated 2026-08-20

Runtime & securityNot independently verified

Source review does not certify behavior or safety.

IN PLAIN ENGLISH

What it does—and when it fits

Diagnosing Bugs is an evidence-first loop for difficult defects and performance regressions. It reads project context and ADRs, redacts secrets from every command and artifact, first builds a tight deterministic pass/fail reproduction, then uses hypotheses, bisection, traces, differential checks, or human-in-the-loop evidence before fixing and adding a regression test.

This is aimed at Engineers investigating hard-to-reproduce bugs. Compare the examples below with your task, then review the limitations, permissions, and risks before installing.

What you get
  • Build a deterministic reproducerTurn a vague report into a small test, fixture, request, trace, or harness.
  • Bisect the causeReduce the search space with explicit hypotheses and controlled comparisons.
  • Lock in the fixVerify the repair in the tight loop and add a regression test.
What makes it different
  • This profile is manually organized around the current upstream SKILL.md workflow.
  • The capability boundary remains explicitly tied to mattpocock/skills.
  • Core uses, limitations, and risks are separated for pre-install review.
Community signalskills.sh All-time: #49 · 669.2K installs

No verified review text is in the current dataset. Use the linked source for the latest discussion.

Read the source note ↗

INSTALL BY AGENT

Choose your Agent

Paths come from official Agent docs or the universal installer behind skills.sh. Compatibility still follows this Skill's record.

Native

This Skill's current record explicitly names this Agent. Still inspect scripts, permissions, and external dependencies first.

Project install (recommended)
npx skills add https://github.com/mattpocock/skills --skill diagnosing-bugs --agent claude-code
Personal install
npx skills add https://github.com/mattpocock/skills --skill diagnosing-bugs --agent claude-code -g

Project install stays with this repository for team sharing. Personal install adds -g and works across repositories.

View install paths
Project path.claude/skills/diagnosing-bugs/
Personal path~/.claude/skills/diagnosing-bugs/
Official agent docs

Claude Code discovers custom Skill folders automatically at project or personal scope.

View path evidence ↗

TYPICAL WORKFLOW

A practical workflow

01

Build a deterministic reproducer

Turn a vague report into a small test, fixture, request, trace, or harness.

02

Bisect the cause

Reduce the search space with explicit hypotheses and controlled comparisons.

03

Lock in the fix

Verify the repair in the tight loop and add a regression test.

THE TRADEOFFS

Advantages and tradeoffs

Notable strengths

  1. This profile is manually organized around the current upstream SKILL.md workflow.
  2. The capability boundary remains explicitly tied to mattpocock/skills.
  3. Core uses, limitations, and risks are separated for pre-install review.

Limitations

  1. It requires a repeatable pass/fail signal; intermittent production-only failures may need observability or human evidence first.
  2. Diagnosis can identify a cause without authorizing invasive production changes or broad refactoring.

COMPARE THE TRADEOFF

Consider these close alternatives

These are deterministic nearby candidates, not paid placements or a universal ranking. Open the full profile before choosing.

01

Same job family · native to Claude Code + Codex

frontend-design

Design constraints that push generated interfaces beyond generic AI UI.
Tradeoff to check
Aesthetic judgments remain subjective and still need stakeholder review.
First risk
Style over function · Medium
Source state
Pinned · 34040c9c
Open frontend-design profile ↗
02

Same job family · native to Codex + Claude Code

web-design-guidelines

Review interfaces against practical web design and accessibility rules.
Tradeoff to check
It depends on network access and a live guideline document whose contents can change over time.
First risk
Rule drift or context-free findings · Medium
Source state
Pinned · 063bee94
Open web-design-guidelines profile ↗
03

Same job family · native to Codex + Claude Code

anti-ui-slop

Instruction-only, product-specific UI design contracts with optional real-interface evidence and a hard finish gate.
Tradeoff to check
Repository evidence is required; UIZZE references or user-provided screenshots are optional, and missing reference evidence should be labeled rather than guessed.
First risk
Copying external interface patterns too literally · Medium
Source state
Pinned · 1f564408
Open anti-ui-slop profile ↗
Compare more in the directory →

BEST FIT

Who it is for

→

Engineers investigating hard-to-reproduce bugs

→

Teams diagnosing performance regressions

BEFORE YOU USE IT

Risks to review before use

High

Secrets captured in diagnostic evidence

Requests, traces, screenshots, and logs can contain tokens, credentials, personal data, or production payloads. Redact before capture, minimize retention, and restrict access to every diagnostic artifact.

Medium

Upstream instruction drift

Behavior can change with upstream updates. Record the commit used for important workflows and review updates before adoption.

SECURITY

What the permission profile means

  • Declared access remains governed by the current upstream SKILL.md and runtime requests.
  • Treat repository files, web content, and tool output as untrusted input.
  • SkillSignal has not independently executed or security-audited this package; external skills.sh labels are not SkillSignal certification.

Not a security certification. External ratings are attributed references. SkillSignal has not independently executed or security-reviewed this Skill.

COMMON QUESTIONS

Diagnosing Bugs Skill FAQ

What is the Diagnosing Bugs Skill?

Diagnosing Bugs is an evidence-first loop for difficult defects and performance regressions. It reads project context and ADRs, redacts secrets from every command and artifact, first builds a tight deterministic pass/fail reproduction, then uses hypotheses, bisection, traces, differential checks, or human-in-the-loop evidence before fixing and adding a regression test.

How do I install the Diagnosing Bugs Skill?

Open and review the listed source, choose the project or personal path for your Agent, then verify the first run in a controlled project. Open the listed skills.sh page and upstream repository; verify the current SKILL.md.

Is the Diagnosing Bugs Skill safe to use?

SkillSignal checked the source on 2026-09-23, but that is not a runtime test or security certification. Review the “Secrets captured in diagnostic evidence” risk first and begin with the least access required.

INSIDE THE PACKAGE

Indexed files

SKILL.mdUpstream Skill instructionsSource-linked

TAGS

debuggingreproductionregression-testing

Manually expanded from the current upstream SKILL.md and linked source at mattpocock/skills, checked 2026-08-20. This is an original summary, not an execution result or security certification.