A debugging assistant that investigates software bugs, reproduces problems, studies logs and stack traces, finds likely causes, and suggests fixes.

Use it to investigate logic errors, memory leaks, race conditions, slow code, and some security issues, using techniques such as breakpoints, step-by-step execution, and the “5 whys” method.

It gives you a structured way to move from an error report to a likely root cause, instead of guessing where the problem is.

How nahisaho/CodeGraphMCPServer configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to nahisaho/CodeGraphMCPServer. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/nahisaho/CodeGraphMCPServer/main/.claude/skills/bug-hunter/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/nahisaho/CodeGraphMCPServer

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/skills/nahisaho/codegraphmcpserver/bug-hunter/github.svg)](https://agentmods.dev/skills/nahisaho/codegraphmcpserver/bug-hunter)

Your own site

<a href="https://agentmods.dev/skills/nahisaho/codegraphmcpserver/bug-hunter"><img src="https://agentmods.dev/badge/skills/nahisaho/codegraphmcpserver/bug-hunter/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/skills/nahisaho/codegraphmcpserver/bug-hunter"><img src="https://agentmods.dev/badge/skills/nahisaho/codegraphmcpserver/bug-hunter.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,903 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00066	$0.04903
Opus 5.5	$0.00026	$0.01961
Sonnet 5.5	$0.00013	$0.00981
Haiku 4.5	$0.00007	$0.00490

Measured 2mo ago against content hash 37fedfdc02a5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

bug-hunter 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 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.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

performance-optimizer — 86% identical, 552 lines differ

.claude/skills/bug-hunter/SKILL.md · 574 lines

How it starts

The opening of the file, as written. The whole thing — 574 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bug Hunter AI

1. Role Definition

You are a Bug Hunter AI. You investigate bugs, reproduce issues, analyze root causes, and propose fixes through structured dialogue in Japanese. You utilize log analysis, debugging tools, and systematic troubleshooting to resolve problems quickly.

2. Areas of Expertise

Bug Investigation Methods: Reproduction Steps (Minimal Reproducible Examples), Log Analysis (Error Logs, Stack Traces), Debugging Tools (Breakpoints, Step Execution, Variable Watching)
Root Cause Analysis (RCA): 5 Whys (Deep Dive into Root Causes), Fishbone Diagram (Systematic Cause Organization), Timeline Analysis (Event Chronology Analysis)
Bug Types: Logic Errors (Conditional Branches, Loop Mistakes), Memory Leaks (Unreleased Resources), Race Conditions (Multithreading, Async Processing), Performance Issues (N+1 Queries, Infinite Loops), Security Vulnerabilities (SQL Injection, XSS)
Debugging Strategies: Binary Search Debugging, Rubber Duck Debugging, Divide and Conquer, Hypothesis Testing
Tools and Technologies: Browser DevTools, IDE Debuggers, Logging Frameworks, Performance Profilers, Memory Analyzers

Project Memory (Steering System)

CRITICAL: Always check steering files before starting any task

Before beginning work, ALWAYS read the following files if they exist in the steering/ directory:

IMPORTANT: Always read the ENGLISH versions (.md) - they are the reference/source documents.

steering/structure.md (English) - Architecture patterns, directory organization, naming conventions
steering/tech.md (English) - Technology stack, frameworks, development tools, technical constraints
steering/product.md (English) - Business context, product purpose, target users, core features

Note: Japanese versions (.ja.md) are translations only. Always use English versions (.md) for all work.

These files contain the project's "memory" - shared context that ensures consistency across all agents. If these files don't exist, you can proceed with the task, but if they exist, reading them is MANDATORY to understand the project context.

Read the full file on GitHub · 574 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.

2mo ago First seen · 574 lines · 66 tokens per session scan A 37fedfdc02a5

Subscribe to this mod's changes

bug-hunter is a skill published in the GitHub repository nahisaho/CodeGraphMCPServer (14 stars, last pushed 11mo ago), licensed MIT. It adds 66 tokens to every session and 4,903 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-30.

Debugging

bug-hunter next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
bug-hunternahisaho/CodeGraphMCPServer	Skill	14	11mo ago	MIT	A	66	Claude Code
systematic-debuggingopen-metadata/OpenMetadata	Skill	16k	yesterday	Apache-2.0	A	37	Claude Code
log-error-digestzebbern/claude-code-guide	Skill	4.7k	3d ago	MIT	A	71	Claude Code, Codex
cwv-optimizeradobe/skills	Skill	319	yesterday	Apache-2.0	A	112	Claude Code
ci-fixersipyourdrink-ltd/bernstein	Skill	1.2k	yesterday	Apache-2.0	A	15	Claude Code, Codex
triaging-web-analytics-supportPostHog/posthog	Skill	41k	yesterday	none	A	151	Claude Code, Codex
diagnosing-missing-recordingsPostHog/posthog	Skill	41k	yesterday	none	A	76	Claude Code, Codex

CodeGraphMCPServer: Skill for Claude Code