fix-bug

fix-bug is a skill for Claude Code from QBall-Inc/the-bulwark. It costs 46 tokens per session (1,962 once invoked), scanned A, original, MIT.

A guided bug-fixing process that investigates a problem, changes the code, and checks that the fix works. It can add or review tests when needed.

In plain words
What is it for?
Use it to investigate reported bugs, repair broken features, handle API failures, and validate fixes with tests.
Why use it?
It prevents an agent from jumping straight to a code change without understanding the cause or checking the result. This is useful for regressions, production errors, and flaky behavior.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: reads .claude/ paths; positional $N argument.

Part of the the-bulwark plugin — 30 skills, 17 agents, 6 hooks shipped together

Good fit Use it to investigate reported bugs, repair broken features, handle API failures, and validate fixes with tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/qball-inc/the-bulwark/fix-bug
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.

Any agent
npx skills add QBall-Inc/the-bulwark --skill fix-bug
Clone the repo
git clone --depth 1 https://github.com/QBall-Inc/the-bulwark

Made for: Claude Code.

Or install the-bulwark, the plugin that ships this one along with the rest of its 30 skills, 17 agents, 6 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for fix-bug

README.md
[![agentmods](https://agentmods.dev/badge/skills/qball-inc/the-bulwark/fix-bug.svg)](https://agentmods.dev/skills/qball-inc/the-bulwark/fix-bug)
Your own site
<a href="https://agentmods.dev/skills/qball-inc/the-bulwark/fix-bug"><img src="https://agentmods.dev/badge/skills/qball-inc/the-bulwark/fix-bug.svg" alt="Measured on agentmods" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,962 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00046 $0.01962
Opus 5 $0.00023 $0.00981
Sonnet 5 $0.00009 $0.00392
Haiku 4.5 $0.00005 $0.00196

Measured 8d ago against content hash e0d099a84509, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

fix-bug 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 8d ago.

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.

skills/fix-bug/SKILL.md · 248 lines

How it starts

The opening of the file, as written. The whole thing — 248 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fix Bug Pipeline

This skill triggers the Fix Validation pipeline to systematically investigate, fix, and validate a bug.

When to Use This Skill

Load this skill when the user request matches ANY of these patterns:

Trigger Pattern Example User Request
Bug fix requests "Fix this bug", "Something is broken in X"
Error investigation "Users report errors in X", "This feature isn't working"
Regression fixes "This used to work", "Breaking after recent changes"
Production issues "Login fails for new accounts", "API returns 500"
Flaky behavior "Tests pass sometimes", "Intermittent failures"

DO NOT use this skill for:

Anti-Pattern Use Instead
Ad-hoc fixes without investigation Direct fix (skip pipeline)
Simple typo corrections Direct edit
Refactoring without reported issues Code Review pipeline
Adding new features New Feature pipeline
Performance optimization Research & Planning pipeline

Why This Skill Exists

Without this skill, conversational prompts like "please investigate and fix this bug" may cause Claude to skip pipeline stages and fix directly. This skill ensures deterministic execution of all Fix Validation pipeline stages.

Usage

/fix-bug <path> [description]

Arguments:

  • $1 (required): Path to code with the bug
  • $2 and beyond (optional): Description of the issue - recommended for better analysis

Examples:

/fix-bug src/auth/login.ts "Users report login fails for new accounts"
/fix-bug tests/fixtures/fix-validator/simple-fix/ "Cannot read property displayName of undefined"
/fix-bug src/api/routes.ts

Pipeline Stages

When invoked, follow the Fix Validation pipeline exactly:

IssueAnalyzer (bulwark-issue-analyzer)          // Sonnet - root cause analysis
|> FixWriter (bulwark-implementer)              // Opus - implement fix
|> (if !tests_cover_scenario                    // Conditional: only if tests don't already exist
    then TestWriter |> TestAudit                // Opus writes, then audit for T1-T4
    else Skip)
|> FixValidator (bulwark-fix-validator)          // Sonnet - validate against debug report
|> CodeReviewer (general-purpose)               // Sonnet - review fix
|> (if !approved
    then IssueAnalyzer                          // Loop back
    else Done)
|> LOOP(max=3)                                  // Max 3 iterations

Read the full file on GitHub · 248 lines

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. 8d ago First seen · 248 lines · 46 tokens per session scan A e0d099a84509

Subscribe to this mod's changes

fix-bug is a skill published in the GitHub repository QBall-Inc/the-bulwark (8 stars, last pushed yesterday), licensed MIT. It adds 46 tokens to every session and 1,962 once invoked, about $0.0002 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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