Mutation Testing
jvm-skills/jvm-skills
Bootstrap pitest via the info.solidsoft.pitest Gradle plugin with Kotlin-sane defaults, run mutation tests scoped to changed classes, interpret surviving mutants from mutations.xml, triage…
Set up and run mutation testing with PIT (pitest) on a Gradle project, and read the mutation score.
Install Mutation Testing
$ npx skills add Amplicode/spring-skills --skill mutation-testing -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install Amplicode/spring-skills mutation-testing --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/Amplicode/spring-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/mutation-testing .claude/skills/mutation-testing && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "mutation-testing" agent skill from https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testing into .claude/skills/mutation-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mutation-testing", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testingType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add Amplicode/spring-skills --skill mutation-testing -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install Amplicode/spring-skills mutation-testing --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Amplicode/spring-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/mutation-testing .agents/skills/mutation-testing && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "mutation-testing" agent skill from https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testing into .agents/skills/mutation-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mutation-testing", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add Amplicode/spring-skills --skill mutation-testing -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install Amplicode/spring-skills mutation-testing --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Amplicode/spring-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/mutation-testing .cursor/skills/mutation-testing && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "mutation-testing" agent skill from https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testing into .cursor/skills/mutation-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mutation-testing", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/Amplicode/spring-skills.git --path skills/mutation-testing--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add Amplicode/spring-skills --skill mutation-testing -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install Amplicode/spring-skills mutation-testing --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Amplicode/spring-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/mutation-testing .gemini/skills/mutation-testing && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "mutation-testing" agent skill from https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testing into .gemini/skills/mutation-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mutation-testing", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install Amplicode/spring-skills mutation-testingInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add Amplicode/spring-skills --skill mutation-testing -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/Amplicode/spring-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/mutation-testing .github/skills/mutation-testing && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "mutation-testing" agent skill from https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testing into .github/skills/mutation-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mutation-testing", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add Amplicode/spring-skills --skill mutation-testing -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install Amplicode/spring-skills mutation-testing --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Amplicode/spring-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/mutation-testing .opencode/skills/mutation-testing && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "mutation-testing" agent skill from https://github.com/Amplicode/spring-skills/tree/main/skills/mutation-testing into .opencode/skills/mutation-testing/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "mutation-testing", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
mutation-testing- GitHub stars
- 126
- Token cost
- ~669 tokens
- SKILL.md length
- 320 words
- Files
- 8 (incl. scripts, references)
- Skills in repo
- 16
- Repo updated
- First seen
- Licence
- None found
At a glance
Set up and run mutation testing with PIT (pitest) on a Gradle project, and read the mutation score.
- Works in 4 steps: Configure PIT in the build → Adjust what gets mutated → Run PIT and report the score → …
- The user wants mutation testing added to a build
- Runs Python scripts from its folder
- Wants a mutation score
What it does
Mutation Testing is an agent skill from Amplicode/spring-skills. Set up and run mutation testing with PIT (pitest) on a Gradle project, and read the mutation score. Use this skill whenever the user wants mutation testing added to a build, configured, run or re-run, wants a mutation score or a mutation report interpreted, asks why a particular mutant survived, or asks what should be excluded from mutation analysis, or wants something added to those exclusions — in any language, and whether or not the tool is named. Also use it when the task calls for it: checking test quality…
Its SKILL.md is about 670 tokens, which your agent loads only when the skill is triggered. The skill folder holds 9 other files, including scripts and reference files (for example `references/add-exclusion.md`, `references/configuration.md` and `references/exclusions.md`).
It sits in Testing & QA, covering Test coverage. It works with Gradle. The repository describes itself as: Amplicode Agent Tools.
When your agent uses it
- The user wants mutation testing added to a build
- Wants a mutation score
- A mutation report interpreted
- Asks why a particular mutant survived
Example prompts
- “/mutation-testing”
Requirements
- Python 3
Workflow steps
4 steps, taken from the step headings in SKILL.md.
- Configure PIT in the build
- Adjust what gets mutated
- Run PIT and report the score
- Record what was resolved
What it can do on your machine
Read from SKILL.md and the folder at commit bf19b3c. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 1 file in scripts/ (Python), which the agent can run.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Mutation Testing loads about 669 tokens when it runs, and up to ~7.4k if it reads all its reference files. Until then it costs about 153 tokens; SKILL.md has 320 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 320 words (~669 tokens).
“Start by reading this skill's own pitest entry for THIS project (type: project) — the checks below are built on it. A missing entry is not an error; it means nothing has been recorded yet.”
- name
- mutation-testing
Files
SKILL.md and 7 other files (scripts, references) in skills/mutation-testing of Amplicode/spring-skills.
- SKILL.md
- references/add-exclusion.md
- references/configuration.md
- references/exclusions.md
- references/junit6.md
- references/report.md
- references/usage.md
- scripts/summarize_mutations.py
Open the folder on GitHubat commit bf19b3c
Compare with similar skills
Mutation Testing next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Mutation Testing this skillAmplicode/spring-skills | 126 | — | ~669 | Automated safety check: Pass | None | |
| Mutation Testingjvm-skills/jvm-skills | 140 | — | ~6.7k | Automated safety check: Pass | Apache-2.0 | |
| Coverage Kover Gradlejvm-skills/jvm-skills | 140 | — | ~301 | Automated safety check: Pass | Apache-2.0 | |
| Test Writing WorkflowiOfficeAI/AionUi | 33k | 1 repos | ~1.2k | Automated safety check: Pass | Apache-2.0 | |
| Evaluate PR Testsdotnet/maui | 23k | — | ~2.9k | Automated safety check: Pass | MIT | |
| Requirementsrizsotto/Bear | 6.5k | — | ~2k | Automated safety check: Pass | GPL-3.0 |
Similar skills
Coverage Kover Gradle
jvm-skills/jvm-skills
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Test Writing Workflow
iOfficeAI/AionUi
Sets the test-writing workflow for the repository: risk-first scenario lists, behavior-focused Vitest tests, a full run before each commit and a coverage target.
- Official
Evaluate PR Tests
dotnet/maui
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Requirements
rizsotto/Bear
Write, modify, or review a requirement file under docs/requirements -- pick the single owning file, keep the text contract-only, name IDs so they need no explanation, and verify cross-references and…
Mutant
mbj/mutant
Run mutant, read mutation reports, fix alive mutations, and verify coverage.
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Questions about Mutation Testing
What does Mutation Testing do?
Set up and run mutation testing with PIT (pitest) on a Gradle project, and read the mutation score. Mutation Testing is an agent skill from Amplicode/spring-skills. Set up and run mutation testing with PIT (pitest) on a Gradle project, and read the mutation score.
When should I use Mutation Testing?
Mutation Testing fits situations like: the user wants mutation testing added to a build; wants a mutation score; A mutation report interpreted; asks why a particular mutant survived.
How do I install Mutation Testing in Claude Code?
Run `npx skills add Amplicode/spring-skills --skill mutation-testing -a claude-code`. Or copy the skill folder (skills/mutation-testing in Amplicode/spring-skills) into .claude/skills/mutation-testing in your project. Claude Code loads it when a task matches its description.
How do I install Mutation Testing in Codex?
Run `npx skills add Amplicode/spring-skills --skill mutation-testing -a codex`. Or copy the skill folder (skills/mutation-testing in Amplicode/spring-skills) into .agents/skills/mutation-testing in your project. Codex loads it when a task matches its description.
Can I use Mutation Testing in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Amplicode/spring-skills --skill mutation-testing -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/mutation-testing, .gemini/skills/mutation-testing, .github/skills/mutation-testing and .opencode/skills/mutation-testing in your project.
What does Mutation Testing need to run?
Going by SKILL.md and its folder, Mutation Testing needs Python for the scripts in its folder. Our summary lists: Python 3.
Does Mutation Testing access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Mutation Testing safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Mutation Testing use?
No licence was found for Mutation Testing or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Mutation Testing use?
About 669 tokens (SKILL.md is roughly 2.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 6.8k tokens, read only when the agent opens those files.
What are the alternatives to Mutation Testing?
Skills that share tags, products or a category with Mutation Testing: Mutation Testing (jvm-skills/jvm-skills, 140 stars), Coverage Kover Gradle (jvm-skills/jvm-skills, 140 stars), Test Writing Workflow (iOfficeAI/AionUi, 33k stars) and Evaluate PR Tests (dotnet/maui, 23k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Mutation Testing?
Amplicode (a GitHub organization) maintains it in Amplicode/spring-skills, which has 126 GitHub stars. The repository holds 16 skills in this directory. The repository was last updated on September 6, 2026.
Source: Amplicode/spring-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.