code-quality-audit

code-quality-audit is a skill for Claude Code from mhylle/claude-skills-collection. It costs 126 tokens per session (3,192 once invoked), scanned A, original, MIT.

A code-quality audit that measures test coverage, code complexity, file size, dependency relationships, and mutation testing. Mutation testing changes code deliberately to check whether tests detect the changes.

In plain words
What is it for?
Use it to check whether tests cover the code, find overly complex or large modules, detect dependency cycles, inspect module connections, and measure how well tests catch injected faults.
Why use it?
It identifies maintainability and testing weaknesses in a codebase and produces a prioritized report or pass/fail result.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the devflow plugin — 38 skills, 13 agents, 5 hooks shipped together

Good fit Use it to check whether tests cover the code, find overly complex or large modules, detect dependency cycles, inspect module connections, and measure how well tests catch injected faults.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mhylle/claude-skills-collection/code-quality-audit
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.

Any agent
npx skills add mhylle/claude-skills-collection --skill code-quality-audit
Clone the repo
git clone --depth 1 https://github.com/mhylle/claude-skills-collection

Made for: Claude Code.

Or install devflow, the plugin that ships this one along with the rest of its 38 skills, 13 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 code-quality-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/mhylle/claude-skills-collection/code-quality-audit/github.svg)](https://agentmods.dev/skills/mhylle/claude-skills-collection/code-quality-audit)
Your own site
<a href="https://agentmods.dev/skills/mhylle/claude-skills-collection/code-quality-audit"><img src="https://agentmods.dev/badge/skills/mhylle/claude-skills-collection/code-quality-audit/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.

agentmods 80×15 button for code-quality-audit

Your own site · 80×15
<a href="https://agentmods.dev/skills/mhylle/claude-skills-collection/code-quality-audit"><img src="https://agentmods.dev/badge/skills/mhylle/claude-skills-collection/code-quality-audit.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 126 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,192 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00126 $0.03192
Opus 5 $0.00063 $0.01596
Sonnet 5 $0.00025 $0.00638
Haiku 4.5 $0.00013 $0.00319

Measured 10d ago against content hash 6b2d78651293, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

code-quality-audit 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 10d 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/code-quality-audit/SKILL.md · 247 lines

How it starts

The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Quality Audit

Systematic audit of a codebase along five axes: test coverage, cyclomatic complexity, module size, dependency structure, and mutation testing. Produces a single prioritized report and, when invoked as a gate, returns a pass/fail verdict.


Scope — what this audits and what it doesn't

This skill measures mechanical code-quality metrics on the current source tree. That's it. Keep this distinction sharp because many user prompts bundle unrelated questions under words like "gate" or "quality":

In scope:

  • Test coverage (line + branch, measured by a coverage tool)
  • Cyclomatic complexity per function (measured by a static analyzer)
  • Module/file size in LOC
  • Dependency graph cycles and fan-in/out
  • Mutation score (tests actually kill injected mutations)

Out of scope — do not attempt:

  • Plan-vs-code auditing ("is phase 3 of PLAN.md actually implemented?") — that's a different task, not this skill
  • Architectural drift from design docs / ADRs
  • Business-logic correctness review
  • Security review (there's a separate security-review skill)
  • Lint / type-check errors (there's verification-loop for that)
  • Whether tests pass — a 100%-failing test suite with 80% coverage still passes this audit's coverage axis. The gate is about measured metrics, not CI health.

If a user's prompt mixes scopes (e.g. "is phase 3 shippable?"), interpret it as: "are my five code-quality metrics within threshold for the code as it stands?" That's the only question this skill answers. Surface the narrow framing in the report's preamble if the prompt was broader, so the user knows what they did and didn't get.


Design Philosophy

Why these five axes?

Each catches a different class of problem that the others miss:

Axis Catches Why it matters
Coverage Untested code paths You can't trust code you haven't exercised
Complexity Hard-to-reason-about functions Complex code hides bugs and resists change
Module size Over-stuffed files Large modules accrete responsibilities and become change-amplifiers
Dependencies Cycles, tight coupling, god-modules Structural debt is expensive to unwind later
Mutation Tests that run code but don't assert meaningfully High coverage with weak assertions is a false sense of safety

Read the full file on GitHub · 247 lines

Files

What ships with it

5 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. 10d ago First seen · 247 lines · 126 tokens per session scan A 6b2d78651293

Subscribe to this mod's changes

code-quality-audit is a skill published in the GitHub repository mhylle/claude-skills-collection (18 stars, last pushed 7d ago), licensed MIT. It adds 126 tokens to every session and 3,192 once invoked, about $0.0006 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.

Related

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