An agent that applies a small, targeted fix after another report has identified a bug.

Use it to implement a documented bug fix without running commands or tests.

It keeps the change limited to the reported problem and leaves testing to a separate verification step.

bug-fixer — Agent for Claude Code by huangjia2019

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.

Clone the repo

git clone --depth 1 https://github.com/huangjia2019/claude-code-engingeering-EN

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/agents/huangjia2019/claude-code-engingeering-en/bug-fixer/github.svg)](https://agentmods.dev/agents/huangjia2019/claude-code-engingeering-en/bug-fixer)

Your own site

<a href="https://agentmods.dev/agents/huangjia2019/claude-code-engingeering-en/bug-fixer"><img src="https://agentmods.dev/badge/agents/huangjia2019/claude-code-engingeering-en/bug-fixer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/agents/huangjia2019/claude-code-engingeering-en/bug-fixer"><img src="https://agentmods.dev/badge/agents/huangjia2019/claude-code-engingeering-en/bug-fixer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 28 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 226 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin 100% copy Near-identical to another mod 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.

Model	Per session	Once invoked
Fable 5.1	$0.00028	$0.00226
Opus 5.5	$0.00011	$0.00090
Sonnet 5.5	$0.00006	$0.00045
Haiku 4.5	$0.00003	$0.00023

Measured 2mo ago against content hash 3a5e5ca702b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

bug-fixer scanned grade B with 1 finding 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 2mo 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.

Unrestricted tool accessmediumExcessive agency

A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.

- Do NOT execute any commands

Origin

This is a copy

100% identical to bug-fixer — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

ch04-subagents/.claude/agents/bug-fixer.md · 34 lines

What it actually says

Bug Fixer Agent

You are a bug fixer specialist. You receive a bug location report and apply the minimal fix.

Process

Read the bug locator's report
Read the affected file to understand full context
Apply the minimal fix — change as few lines as possible
Verify your fix doesn't break the surrounding logic

Output Format

## Fix Applied
- **File**: [file path]
- **Change**: [what was changed]
- **Before**: [old code]
- **After**: [new code]
- **Reasoning**: [why this fix is correct]

Rules

Apply the MINIMAL fix — don't refactor surrounding code
Do NOT run tests (that's the verifier's job)
Do NOT execute any commands
If the bug report is unclear, report back — don't guess

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.

2mo ago First seen · 34 lines · 28 tokens per session scan B 3a5e5ca702b8

Subscribe to this mod's changes

bug-fixer is an agent published in the GitHub repository huangjia2019/claude-code-engingeering-EN (10 stars, last pushed 4mo ago), licensed MIT. It adds 28 tokens to every session and 226 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it B with 1 finding (unrestricted tool access). It is 100% identical to bug-fixer, differing in 0 lines, and is treated as a copy.

Debugging

bug-fixer next to 6 agents from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
bug-fixerhuangjia2019/claude-code-engingeering-EN	Agent	10	4mo ago	MIT	B	28	Claude Code
review-obsidian-guidelinesuphy/obsidian-reminder	Agent	662	2d ago	MIT	A	63	Claude Code
debuggerTT-Wang/forge	Agent	35	3d ago	MIT	A	17	Claude Code
debuggerbostonaholic/rpikit	Agent	19	5d ago	MIT	A	28	Claude Code
loom-advisorcosmix/loom	Agent	65	6d ago	MIT	A	53	Claude Code
evolve-retrospectivemickeyyaya/evolve-loop	Agent	6	today	Apache-2.0	A	51	Claude Code
type-reconstructormarcosd4h/DeepExtractRuntime	Agent	21	1mo ago	MIT	A	63	Claude Code

bug-fixer