nxtcm-components: Skill for Claude Code

.agents/skills/stryker-mutation-test/SKILL.md

stryker-mutation-test is a skill for Claude Code, Codex from RedHatInsights/nxtcm-components. It costs 76 tokens per session (1,224 once invoked), scanned A, original, Apache-2.0.

A command builder for Stryker, a tool that checks test quality by making small changes to code and seeing whether tests catch them. It prepares mutation-testing commands for Playwright component tests.

In plain words
What is it for?
Use it to create a copy-paste command for checking a component, test area, or feature, optionally with an HTML report or limited parallel work.
Why use it?
It removes the need to remember the right files, flags, and command format. You still run the command yourself in a terminal.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is RedHatInsights/nxtcm-components's own configuration. It tells Claude Code and Codex how to work on nxtcm-components itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything nxtcm-components configures →

Reuse

Borrowing it

Nothing to install: this file belongs to RedHatInsights/nxtcm-components. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/RedHatInsights/nxtcm-components/main/.agents/skills/stryker-mutation-test/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/RedHatInsights/nxtcm-components

Made for: Claude Code, Codex.

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 stryker-mutation-test

README.md
[![agentmods](https://agentmods.dev/badge/skills/redhatinsights/nxtcm-components/stryker-mutation-test.svg)](https://agentmods.dev/skills/redhatinsights/nxtcm-components/stryker-mutation-test)
Your own site
<a href="https://agentmods.dev/skills/redhatinsights/nxtcm-components/stryker-mutation-test"><img src="https://agentmods.dev/badge/skills/redhatinsights/nxtcm-components/stryker-mutation-test.svg" alt="Measured on agentmods" height="20"></a>
Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,224 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.
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 $0.00076 $0.01224
Opus 5 $0.00038 $0.00612
Sonnet 5 $0.00015 $0.00245
Haiku 4.5 $0.00008 $0.00122

Measured 7d ago against content hash 6c45c525e0cd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

stryker-mutation-test 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 7d 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.

.agents/skills/stryker-mutation-test/SKILL.md · 121 lines

How it starts

The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Stryker mutation test command builder

Construct the correct npm run test:stryker command from what the user says. Never run it (no Shell, no npm run test:stryker). Give the user a copy-paste command and ask them to run it locally.

Workflow

  1. Parse the request — which component(s) or test file(s) did they mean?
  2. Resolve paths — map names to repo-relative *.tsx component files (not specs).
  3. Add flags--report, STRYKER_CONCURRENCY when appropriate.
  4. Output — one fenced bash block + short notes (runtime, prerequisites).
  5. Ask the user to run the command in their terminal and paste results if they want help interpreting them.

Command shape

npm run test:stryker -- [stryker-target flags] <component.tsx> [more-components.tsx ...]

With HTML report:

npm run test:stryker:report -- <component.tsx> [more...]
# same as: npm run test:stryker -- --report <component.tsx> ...

Optional env prefix (parallel workers, default is min(4, max(1, cpuCount - 1))):

STRYKER_CONCURRENCY=2 npm run test:stryker -- <component.tsx>

Resolving what to mutate

Pass the component .tsx file, never the .spec.tsx.

User says Resolve to
FieldWithAPIErrorAlert packages/nxtcm-rosa-hcp-wizard/src/components/FieldWithAPIErrorAlert.tsx
FieldWithAPIErrorAlert.spec.tsx Same component path (strip .spec)
rosa hcp footer / RosaHcpWizardFooter packages/nxtcm-rosa-hcp-wizard/src/Footer/RosaHcpWizardFooter.tsx
src/components/Foo (any package) packages/<package>/src/components/Foo/Foo.tsx (confirm file exists)
Ambiguous basename Search with Glob; if multiple matches, ask the user to pick

All paths must be repo-relative from the monorepo root (include the packages/<package>/ prefix when the component lives in a workspace package, not just src/...).

If the user names a spec or you're unsure of the subject, read the .spec.tsx file and trace the mount target and imports to the co-located *.tsx component.

Read the full file on GitHub · 121 lines

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. 7d ago First seen · 121 lines · 76 tokens per session scan A 6c45c525e0cd

Subscribe to this mod's changes

stryker-mutation-test is a skill published in the GitHub repository RedHatInsights/nxtcm-components (3 stars, last pushed today), licensed Apache-2.0. It adds 76 tokens to every session and 1,224 once invoked, about $0.0004 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 2026-08-31.

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