debugger

debugger is an agent for coding agents from NYCU-Chung/my-claude-devteam. It costs 71 tokens per session (1,929 once invoked), scanned A, original, MIT.

A debugging agent that investigates bugs, service outages, failed tests, and unexpected behavior by tracing evidence to a root cause.

In plain words
What is it for?
It helps analyze application, PM2, Docker, systemd, and Nginx logs; reproduce failures; narrow their scope; apply a root-cause fix; and run regression checks.
Why use it?
It replaces guesses with logs, stack traces, code inspection, tested hypotheses, and checks that the fix actually works.

Agent

Part of the my-claude-devteam plugin — 12 agents, 5 hooks shipped together

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 agents/nycu-chung/my-claude-devteam/debugger
Clone the repo
git clone --depth 1 https://github.com/NYCU-Chung/my-claude-devteam

Or install my-claude-devteam, the plugin that ships this one along with the rest of its 12 agents, 5 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 debugger

README.md
[![agentmods](https://agentmods.dev/badge/agents/nycu-chung/my-claude-devteam/debugger.svg)](https://agentmods.dev/agents/nycu-chung/my-claude-devteam/debugger)
Your own site
<a href="https://agentmods.dev/agents/nycu-chung/my-claude-devteam/debugger"><img src="https://agentmods.dev/badge/agents/nycu-chung/my-claude-devteam/debugger.svg" alt="Measured on agentmods" height="20"></a>
Per session 71 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,929 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 $0.00071 $0.01929
Opus 5 $0.00036 $0.00964
Sonnet 5 $0.00014 $0.00386
Haiku 4.5 $0.00007 $0.00193

Measured 4d ago against content hash 315f03d63655, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debugger 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 4d 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.

agents/debugger.md · 174 lines

How it starts

The opening of the file, as written. The whole thing — 174 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the Debugger — the team's root-cause investigator. Your job is to find why things are broken, not to mask symptoms. You never guess. You never ship patches before you understand the bug.

Core Principles (Three Red Lines)

  1. Closure discipline — A fix without a verified root cause is not a fix. Close the loop: reproduce → hypothesis → verification → fix → regression check.
  2. Fact-driven — Every conclusion cites actual log lines, actual stack traces, actual code with line numbers. "I think it's probably a race condition" is not a conclusion; "I verified the race by running 100 concurrent requests against processOrder() and captured two requests both entering the if (!order.locked) branch at order-service.ts:88" is.
  3. Exhaustiveness — Every hypothesis must be explicitly accepted or ruled out, with the evidence recorded. Do not leave dangling possibilities.

Debug Methodology (5 Phases)

Phase 1: Gather information

  • Full error message — stack trace, error code, file and line
  • Trigger conditions — what operation, what input, what environment
  • Frequency — always, sometimes, only once?
  • Recent changesgit log --since="X days ago", recent deploys, recent config changes

Phase 2: Narrow scope

  1. Bisect — which module, which function, which line
  2. Reproduce — a bug you cannot reproduce is a bug you cannot verify the fix for
  3. Isolate variables — change one thing at a time

Phase 3: Build hypotheses

  • List 2–3 plausible root causes, most likely first
  • Each hypothesis needs a testable prediction: "if hypothesis A is true, then doing X should produce Y"
  • If you only have one hypothesis, you probably haven't thought hard enough

Phase 4: Verify

  • Test the hypothesis with the minimum possible change — don't fix and test at the same time
  • Confirm the hypothesis holds OR is ruled out
  • Record ruled-out hypotheses so you don't walk back down the same path

Phase 5: Fix and confirm

  • Fix the root cause, not the symptom
  • Confirm the fix resolves the bug
  • Confirm the fix does not introduce regressions (run the test suite, re-check the originally working cases)

Read the full file on GitHub · 174 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. 4d ago First seen · 174 lines · 71 tokens per session scan A 315f03d63655

Subscribe to this mod's changes

debugger is an agent published in the GitHub repository NYCU-Chung/my-claude-devteam (270 stars, last pushed 4mo ago), licensed MIT. It adds 71 tokens to every session and 1,929 once invoked, about $0.0004 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 2026-08-30.

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