# Crap Analysis

Analyze code coverage and CRAP (Change Risk Anti-Patterns) scores to identify high-risk...

- Repository: https://github.com/Aaronontheweb/dotnet-skills (1244 stars)
- Category: Engineering
- License: MIT
- Last updated: 2026-10-28
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add Aaronontheweb/dotnet-skills --skill crap-analysis -g -a claude-code -y`
Codex: `npx skills add Aaronontheweb/dotnet-skills --skill crap-analysis -g -a codex -y`
Cursor: `npx skills add Aaronontheweb/dotnet-skills --skill crap-analysis -g -a cursor -y`
Gemini CLI: `npx skills add Aaronontheweb/dotnet-skills --skill crap-analysis -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add Aaronontheweb/dotnet-skills`

## Description

Analyze code coverage and CRAP (Change Risk Anti-Patterns) scores to identify high-risk code. Use OpenCover format with ReportGenerator for Risk Hotspots showing cyclomatic complexity and untested code paths.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# CRAP Score Analysis

## When to Use This Skill

Use this skill when:
- Evaluating code quality and test coverage before changes
- Identifying high-risk code that needs refactoring or testing
- Setting up coverage collection for a .NET project
- Prioritizing which code to test based on risk
- Establishing coverage thresholds for CI/CD pipelines

---

## What is CRAP?

**CRAP Score = Complexity x (1 - Coverage)^2**

The CRAP (Change Risk Anti-Patterns) score combines cyclomatic complexity with test coverage to identify risky code.

| CRAP Score | Risk Level | Action Required |
|------------|------------|-----------------|
| **< 5** | Low | Well-tested, maintainable code |
| **5-30** | Medium | Acceptable but watch complexity |
| **> 30** | High | Needs tests or refactoring |

### Why CRAP Matters

- **High complexity + low coverage = danger**: Code that's hard to understand AND untested is risky to modify
- **Complexity alone isn't enough**: A complex method with 100% coverage is safer than a simple method with 0%
- **Focuses effort**: Prioritize testing on complex code, not simple getters/setters

### CRAP Score Examples

| Method | Complexity | Coverage | Calculation | CRAP |
|--------|------------|----------|-------------|------|
| `GetUserId()` | 1 | 0% | 1 x (1 - 0)^2 | **1** |
| `ParseToken()` | 54 | 52% | 54 x (1 - 0.52)^2 | **12.4** |
| `ValidateForm()` | 20 | 0% | 20 x (1 - 0)^2 | **20** |
| `ProcessOrder()` | 45 | 20% | 45 x (1 - 0.20)^2 | **28.8** |
| `ImportData()` | 80 | 10% | 80 x (1 - 0.10)^2 | **64.8** |

---

## Coverage Collection Setup

### coverage.runsettings

Create a `coverage.runsettings` file in your repository root. The **OpenCover format is required** for CRAP score calculation because it includes cyclomatic complexity metrics.

The rest: https://github.com/Aaronontheweb/dotnet-skills/blob/HEAD/skills/crap-analysis/SKILL.md