Performance Smell Detection

by decebals

Performance Smell Detection is a Quality skill for Claude Code, published by decebals in claude-code-java.

714 stars142 forkson decebals/claude-code-javaAdded 2026/08/23+1% in starsRepository updated 2026/02/08

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ai-assisted-developmentclaude-codeclaude-code-skillsdeveloper-toolsjava

Install in seconds

Install Performance Smell Detection

Copy Performance Smell Detection into your Claude Code skills folder. Run the command in your terminal, or review the source on GitHub before installing.

terminal

npx degit https://github.com/decebals/claude-code-java/tree/main/.claude/skills/performance-smell-detection ~/.claude/skills/performance-smell-detection

Requires Node.js. Downloads this skill only — not the rest of the repository — into your Claude Code skills folder.

Without Node.js

git clone https://github.com/decebals/claude-code-java.git

Clones the whole repository, then copy the skill’s own directory into your skills folder yourself.

In this catalog

Source file: .claude/skills/performance-smell-detection/SKILL.md in decebals/claude-code-java
Installs to: ~/.claude/skills/performance-smell-detection
Collection: One of 18 skills cataloged from this repository
Category: Quality — 1354 skills

What Performance Smell Detection does

Performance Smell Detection identifies potential Java performance smells in code such as regex compilation, boxing, stream overhead, and inefficient collection use. Use it when reviewing hot paths or measured slowdowns, and measure before changing code.

Performance Smell Detection is cataloged under Quality on DirSkills. Performance Smell Detection comes from a repository tagged ai-assisted-development, claude-code, claude-code-skills, developer-tools and java.

Documentation

README

Excerpt

Performance Smell Detection Skill

Identify potential code-level performance issues in Java code.

Philosophy

"Premature optimization is the root of all evil" - Donald Knuth

This skill helps you notice potential performance smells, not blindly "fix" them. Modern JVMs (Java 21/25) are highly optimized. Always:

Measure first - Use JMH, profilers, or production metrics
Focus on hot paths - 90% of time spent in 10% of code
Consider readability - Clear code often matters more than micro-optimizations

When to Use

Reviewing performance-critical code paths
Investigating measured performance issues
Learning about Java performance patterns
Code review with performance awareness

Scope

This is the opening of the README. Read the full README on GitHub.

Frequently asked about Performance Smell Detection

What else does decebals publish alongside Performance Smell Detection?
Performance Smell Detection is one of 18 skills that DirSkills catalogs from decebals/claude-code-java, the repository it ships in. Its siblings there include API Contract Review, Architecture Review and Changelog Generator. Each one is a separate skill with its own page in this directory, installs the same way Performance Smell Detection does, and is maintained by decebals in that same repository. The rest of the collection is listed on the decebals/claude-code-java page.
How does Performance Smell Detection compare to other Quality skills?
Performance Smell Detection ranks #1038 by stars among the 1354 Quality skills in this catalog. The most-starred ones next to it are Benchmark, Benchmark Optimization Loop and API Design Patterns. DirSkills ranks by the star count of the repository each skill ships in, so that order reflects how popular those repositories are rather than any review of Performance Smell Detection against them. Open each page to compare what they document and how they install.