Code Review & Testing · IN-DEPTH PROFILE

diagnosing-bugs

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

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 2026-08-20

Pinned revision · 885e2ca4

Open pinned commit
SkillSignal profileSource-grounded

Updated 2026-08-20

Runtime & securityNot independently verified

Source review does not certify behavior or safety.

30-SECOND BRIEF

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.

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 scope.claude/skills/diagnosing-bugs/
Personal scope~/.claude/skills/diagnosing-bugs/

Use project scope for team sharing and personal scope across repositories. The installer defaults to project scope; add -g for personal scope.

Install command (project scope)npx skills add mattpocock/skills --skill diagnosing-bugs --agent claude-code
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.

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.

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.