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Diagnosing Bugs

Diagnosing Bugs is an agent skill (a SKILL.md file) from mattpocock/skills. Diagnosis loop for hard bugs and performance regressions. It works with Claude Code and Codex and has 278,361 GitHub stars across a repository of 15 listed skills. Install it by copying the skill folder into your agent's skills directory.

github.com/mattpocock/skills/skills/engineering/diagnosing-bugs (opens in a new tab)

  • Multi-skill repo
  • Plugin marketplace
  • Testing & QA
  • Actively maintained
View on GitHub (opens in a new tab)View on skills.sh (opens in a new tab)

Add this skill

Claude

This repository is a Claude Code plugin marketplace. In Claude Code:

/plugin marketplace add mattpocock/skills
/plugin install mattpocock-skills@mattpocock

In the Claude apps, zip the diagnosing-bugs folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).

ChatGPT / Codex

Codex reads skills from .agents/skills/ in a repo or ~/.agents/skills/ for every project:

git clone --depth 1 https://github.com/mattpocock/skills.git
cp -r skills/skills/engineering/diagnosing-bugs .agents/skills/diagnosing-bugs   # repo; ~/.agents/skills for all projects

Standalone skills also load in the ChatGPT desktop app.

Cursor

Cursor loads skills from .cursor/skills/ (or ~/.cursor/skills/) and also reads .claude/skills/:

git clone --depth 1 https://github.com/mattpocock/skills.git
cp -r skills/skills/engineering/diagnosing-bugs .cursor/skills/diagnosing-bugs   # project; ~/.cursor/skills for all projects

Source (checked Oct 7, 2026): code.claude.com/docs/en/skills (opens in a new tab), code.claude.com/docs/en/plugin-marketplaces (opens in a new tab), support.claude.com/en/articles/12512180-using-skills-in-claude (opens in a new tab), learn.chatgpt.com/docs/build-skills (opens in a new tab), cursor.com/docs/context/skills (opens in a new tab)

What this skill does

Diagnosis loop for hard bugs and performance regressions. Use when the user says "diagnose"/"debug this", or reports something broken/throwing/failing/slow. A discipline for hard bugs. Skip phases only when explicitly justified.

When it triggers

  • Use when the user says "diagnose"/"debug this", or reports something broken/throwing/failing/slow.
  • "diagnose"
  • "debug this"

More skills in mattpocock/skills

15 skills are listed from this repository.

Similar skills

More testing & qa skills

All Testing & QA

FAQ

Diagnosing Bugs FAQ

Still curious? Email info@appsgit.com.

What is the Diagnosing Bugs skill?

Diagnosing Bugs is an agent skill (a SKILL.md file) from mattpocock/skills. Diagnosis loop for hard bugs and performance regressions. It works with Claude Code and Codex and has 278,361 GitHub stars across a repository of 15 listed skills. Install it by copying the skill folder into your agent's skills directory. Its SKILL.md lives at github.com/mattpocock/skills/skills/engineering/diagnosing-bugs.

How do I install the Diagnosing Bugs skill?

In Claude Code, run /plugin marketplace add mattpocock/skills and then /plugin install mattpocock-skills@mattpocock. For Codex or Cursor, copy the diagnosing-bugs folder into .agents/skills/ or .cursor/skills/.

Is the Diagnosing Bugs skill free?

Yes. The repository is open source under the MIT license.

Is Diagnosing Bugs maintained?

The repository's most recent commit was on Oct 6, 2026. Its latest release is v1.3.1. appsgit only lists skills from repositories with a commit in the last six months.