bugfix

A lightweight workflow for fixing a clearly described software defect. It documents the bug with a Five Whys analysis, which repeatedly asks why the problem occurred to find its underlying cause, then adds regression tests and creates a pull request.

In plain words
What is it for?
Use it for bugs that can be understood and fixed within a few hours, to record the cause, change the code, add a test, and prepare the fix for review.
Why use it?
It gives small bugs a focused path from report to verified fix. The regression test helps ensure the same defect does not return.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/abilenduke/copilot-developer/bugfix
Any agent
npx skills add ABilenduke/copilot-developer --skill bugfix
Clone the repo
git clone --depth 1 https://github.com/ABilenduke/copilot-developer

Made for: Claude Code, Codex.

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,666 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00064 $0.01666
Opus 5 $0.00032 $0.00833
Sonnet 5 $0.00013 $0.00333
Haiku 4.5 $0.00006 $0.00167

Measured yesterday against content hash 2d813b7c78b5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

bugfix scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/bugfix/SKILL.md · 191 lines

How it starts

The opening of the file, as written. The whole thing — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bugfix Skill

Purpose

This skill handles lightweight bug fixes — problems that can be described in one document and fixed in a few hours. If the fix requires planning, designing, and roadmapping, promote it to a story instead (the brief.md explains the bug and its impact instead of a business case).

Pipeline position: Bug reported → /bugfix → bug doc + fix + tests → PR → merge


First Steps

When this skill is invoked:

  1. Read the template: templates/bug-template.md
  2. Understand the bug: Ask the user what's broken, or investigate if they've provided a description
  3. Determine the feature: Which feature does this bug belong to?
    • If the feature exists in docs/features/, the bug doc goes in docs/features/{feature}/bugs/
    • If it's cross-cutting or unclear, ask the user
  4. Assess scope: Can this be fixed in a few hours with one document?
    • If yes → proceed with bugfix
    • If no → suggest promoting to a story: "This looks bigger than a quick fix. Consider running /research story to create a proper story for it."
  5. Begin the fix process

Process

Phase 1: Document the Bug

  1. Create the bug document at docs/features/{feature}/bugs/{YYYY-MM-DD}_{short-description}.md
  2. Fill in using templates/bug-template.md:
    • Symptoms: What the user/developer sees
    • Steps to Reproduce: Numbered steps to trigger the bug
    • Expected vs Actual: Clear comparison
    • Severity: Critical / High / Medium / Low

Phase 2: Investigate Root Cause

  1. Trace the bug through the codebase
  2. Apply Five Whys analysis:
    • Why 1: [surface cause — what directly caused the symptom]
    • Why 2: [deeper cause — why that happened]
    • Why 3: [root cause — the systemic issue, or as deep as meaningful]
    • Continue only if the root cause isn't clear yet (not all bugs need all 5)
    • Stop when you reach a systemic cause: process gap, missing validation, architectural limitation
  3. Document findings in the bug doc's "Root Cause — Five Whys" section

Read the full file on GitHub · 191 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 191 lines · 64 tokens per session scan A 2d813b7c78b5

Subscribe to this mod's changes

bugfix is a skill published in the GitHub repository ABilenduke/copilot-developer (4 stars, last pushed 6mo ago), licensed MIT. It adds 64 tokens to every session and 1,666 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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