systematic-debugging

systematic-debugging is a skill for Claude Code, Codex from andreymudri/claude-teammates. It costs 29 tokens per session (1,034 once invoked), scanned A, original, MIT.

A step-by-step method for finding the root cause of bugs, failed tests, and unexpected behaviour before changing code.

In plain words
What is it for?
Reproducing bugs, narrowing failures, testing debugging hypotheses, and choosing fixes based on observed evidence.
Why use it?
It reduces guesswork by requiring a reliable reproduction, a smaller test case, and evidence for each possible cause.

Skill for Claude CodeCodex

Part of the claude-teammates plugin — 14 skills, 3 agents, 2 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 skills/andreymudri/claude-teammates/systematic-debugging
Any agent
npx skills add andreymudri/claude-teammates --skill systematic-debugging
Clone the repo
git clone --depth 1 https://github.com/andreymudri/claude-teammates

Made for: Claude Code, Codex.

Or install claude-teammates, the plugin that ships this one along with the rest of its 14 skills, 3 agents, 2 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 systematic-debugging

README.md
[![agentmods](https://agentmods.dev/badge/skills/andreymudri/claude-teammates/systematic-debugging.svg)](https://agentmods.dev/skills/andreymudri/claude-teammates/systematic-debugging)
Your own site
<a href="https://agentmods.dev/skills/andreymudri/claude-teammates/systematic-debugging"><img src="https://agentmods.dev/badge/skills/andreymudri/claude-teammates/systematic-debugging.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,034 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 5.1 $0.00029 $0.01034
Opus 5 $0.00015 $0.00517
Sonnet 5 $0.00006 $0.00207
Haiku 4.5 $0.00003 $0.00103

Measured 5d ago against content hash 3684ff08ca19, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

systematic-debugging 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 5d 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/systematic-debugging/SKILL.md · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Systematic Debugging

Adapted from the MIT-licensed superpowers plugin by Jesse Vincent. See NOTICE.md.

Overview

Core principle: find the root cause before attempting a fix. A fix aimed at a symptom without a confirmed cause is a guess, and guesses are how debugging sessions run for hours without progress.

The Loop

One step at a time. Do not skip ahead to a fix because the cause "seems obvious."

  1. Reproduce reliably. Trigger the bug on demand, with exact steps. If you can't reproduce it consistently, gather more evidence before doing anything else — don't guess at a fix for a bug you can't summon.
  2. Minimise the reproduction. Strip away everything not required to trigger it: unrelated setup, unrelated input, unrelated code paths. A smaller reproduction narrows where the cause can be.
  3. State a hypothesis that predicts something observable. "I think X is the cause because Y, and if true then Z will happen when I do W." A hypothesis that can't fail — one with no observable prediction — is not a hypothesis, it's a guess wearing a hypothesis's clothes.
  4. Instrument to test it. Add logging, a debugger breakpoint, or a targeted probe that checks the prediction from step 3. Run it once. Read the result against what you predicted, not against what you hoped.
  5. Fix the confirmed root cause. Not the nearest symptom, not a defensive check that papers over it — the thing step 4 confirmed.
  6. Add a regression test that fails without the fix. Apply the test-driven-development skill: write the test, confirm it fails for the bug's actual symptom, then confirm the fix makes it pass. Skipping this step means nothing stops the bug from coming back.

One change at a time

Change exactly one thing between test runs. Two simultaneous changes make the result uninterpretable: if the bug clears, you don't know which change fixed it or whether they cancelled each other out; if it doesn't, you don't know which change to keep. This holds even under time pressure — especially under time pressure, since that's when bundling changes feels fastest and costs the most.

Read the full file on GitHub · 90 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. 5d ago First seen · 90 lines · 29 tokens per session scan A 3684ff08ca19

Subscribe to this mod's changes

systematic-debugging is a skill published in the GitHub repository andreymudri/claude-teammates (2 stars, last pushed 3d ago), licensed MIT. It adds 29 tokens to every session and 1,034 once invoked, about $0.0001 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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