How do I install the Exp Test Gap Analysis Claude Code skill?

Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/exp-test-gap-analysis/SKILL.md and restart Claude Code. Both flows are detailed at https://claudskills.com/install/.

Is this skill free to install?

Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.

ClaudSkills / Engineering / testing

Exp Test Gap Analysis

Category: Engineering · Sub-category: testing · Last updated: 2026-05-21

Performs pseudo-mutation analysis on .NET production code to find gaps in existing test suites. Use when the user asks to find weak tests, discover untested edge cases, check if tests would catch a bug, or evaluate test effectiveness through mutation-style reasoning. Analyzes production code for mutation points (boundary conditions, boolean flips, null returns, exception removal, arithmetic changes) and checks whether existing tests would detect each mutation. Works with MSTest, xUnit, NUnit, and TUnit. DO NOT USE FOR: writing new tests (use writing-mstest-tests), detecting test anti-patterns (use test-anti-patterns), measuring assertion diversity (use exp-assertion-quality), or running actual mutation testing tools.

From the source SKILL.md

Analyze .NET production code by reasoning about hypothetical mutations and checking whether existing tests would catch them. This reveals blind spots where tests pass but would continue to pass even if the code were broken.

What this skill does

Exp Test Gap Analysis is a community-contributed Claude Code skill in the testing sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/exp-test-gap-analysis/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when the user asks to find weak tests, discover untested edge cases, check if tests would catch a bug, or evaluate test effectiveness through mutation-style reasoning. Analyzes production code for mutation points (boundary conditions, boolean flips, null returns, exception removal, arithmetic changes) and checks whether existing tests would detect each mutation.

Who uses this skill

The Exp Test Gap Analysis Claude Code skill is built for software engineers, backend developers, full-stack teams, and technical leads building and maintaining production systems. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 70,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/exp-test-gap-analysis
curl -L https://claudskills.com/skills/exp-test-gap-analysis/SKILL.md \
  -o ~/.claude/skills/exp-test-gap-analysis/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/exp-test-gap-analysis/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/exp-test-gap-analysis/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\exp-test-gap-analysis\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Attribution & license

License: MIT

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA

ClaudSkills. (2026). Exp Test Gap Analysis [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/exp-test-gap-analysis/

BibTeX

@misc{exp-test-gap-analysis-2026,
  author    = {ClaudSkills},
  title     = {Exp Test Gap Analysis [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/exp-test-gap-analysis/}
}

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