debug

debug is a skill for Claude Code, Codex from melodic-software/claude-code-plugins. It costs 171 tokens per session (4,100 once invoked), scanned A, original, MIT.

A six-phase method for diagnosing broken software behaviour: create a repeatable check, reproduce the problem, test possible causes, add measurements, fix it with a regression test, and clean up.

In plain words
What is it for?
It helps investigate interface bugs, unexpected logs, production symptoms, and performance regressions, then verifies the fix does not bring the problem back.
Why use it?
It prevents debugging from becoming guesswork by requiring evidence before choosing a cause or declaring the problem fixed.

Skill for Claude CodeCodex

Installs and runs on its own, but its text points at files inside its plugin — anything it tells you to read at a ${CLAUDE_PLUGIN_ROOT} path is only there once the plugin is installed. Installing the plugin gets both.

Part of the debugging plugin — 1 skill 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/melodic-software/claude-code-plugins/debug
Any agent
npx skills add melodic-software/claude-code-plugins --skill debug
Clone the repo
git clone --depth 1 https://github.com/melodic-software/claude-code-plugins

Made for: Claude Code, Codex.

Or install debugging, the plugin that ships this one along with the rest of its 1 skill.

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 debug

README.md
[![agentmods](https://agentmods.dev/badge/skills/melodic-software/claude-code-plugins/debug.svg)](https://agentmods.dev/skills/melodic-software/claude-code-plugins/debug)
Your own site
<a href="https://agentmods.dev/skills/melodic-software/claude-code-plugins/debug"><img src="https://agentmods.dev/badge/skills/melodic-software/claude-code-plugins/debug.svg" alt="Measured on agentmods" height="20"></a>
Per session 171 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,100 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 $0.00171 $0.04100
Opus 5 $0.00086 $0.02050
Sonnet 5 $0.00034 $0.00820
Haiku 4.5 $0.00017 $0.00410

Measured yesterday against content hash 86ad5228a1cb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debug 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 yesterday.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/hitl-loop.template.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

plugins/debugging/skills/debug/SKILL.md · 193 lines

How it starts

The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pre-computed context

Current branch: !git branch --show-current 2>/dev/null || echo "unknown" Recent commits: !git log --oneline -10 2>/dev/null || echo "no commits" Working tree status (empty = clean): !{ git status --porcelain 2>/dev/null || echo "(git status unavailable)"; } | head -10

Variables

Arguments: $ARGUMENTS

Purpose

Hard bugs are won or lost in Phase 1. Without a fast, deterministic, agent-runnable signal that says "bug present / bug fixed", every later phase is guessing. Most failed debugging sessions fail because the engineer skipped straight to hypothesising without building a loop.

This skill enforces the discipline. Six phases, each with a clear gate before the next. The middle three (hypothesise → instrument → fix) are mechanical once Phase 1 is solid; the bookends (loop, cleanup) are the load-bearing work.

Scope boundary: this skill starts from an observed failure: UI behaving wrong, a log line that should not appear, a performance regression, a screenshot of a bug, a production symptom. Its first job is to construct a reproduction loop. If the symptom is already a failing test with no reproduction gap, you do not need this skill. Cycle that test directly (reproduce → fix → retest → regression). What /debugging:debug adds over a bare fix loop is a critical edge case: if no correct test seam exists, that absence IS the finding, filed as an architectural recommendation, not a forced test in the wrong place.

Adapting to your environment (graceful degrade)

This skill is self-contained. Where a phase below names an adjacent capability, such as a test-investigation routine, a TDD helper, a headless-browser driver, an architecture-audit agent, an issue tracker, or an outcome-verifier, treat it as optional: if your environment provides that capability (a skill, plugin, agent, or tool), invoke it; otherwise proceed with the inline guidance given here, which stands on its own. Never block a phase because an adjacent tool is absent. Consumer-specific conventions (naming, module layout, banned APIs, work-notes location) come from your own project's CLAUDE.md and tool config. Read them; this skill does not assume them.

Read the full file on GitHub · 193 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 193 lines · 171 tokens per session scan A 86ad5228a1cb

Subscribe to this mod's changes

debug is a skill published in the GitHub repository melodic-software/claude-code-plugins (14 stars, last pushed yesterday), licensed MIT. It adds 171 tokens to every session and 4,100 once invoked, about $0.0009 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 2026-09-03.