verifying-change-coverage

verifying-change-coverage is a skill for Claude Code from jaktestowac/awesome-copilot-for-testers. It costs 97 tokens per session (2,290 once invoked), scanned A, original, MIT.

A check that measures whether tests actually execute the lines and branches changed in a pull request. Diff coverage means measuring only the code changed by that request, rather than the whole repository.

In plain words
What is it for?
It helps identify untested new code and turn high-risk uncovered changes into a blocking CI finding.
Why use it?
Whole-project coverage can hide an untested new change behind thousands of unrelated tested lines.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Good fit It helps identify untested new code and turn high-risk uncovered changes into a blocking CI finding.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add jaktestowac/awesome-copilot-for-testers --skill verifying-change-coverage
Clone the repo
git clone --depth 1 https://github.com/jaktestowac/awesome-copilot-for-testers

Made for: Claude Code.

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 verifying-change-coverage

README.md
[![agentmods](https://agentmods.dev/badge/skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage/github.svg)](https://agentmods.dev/skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage)
Your own site
<a href="https://agentmods.dev/skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage"><img src="https://agentmods.dev/badge/skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for verifying-change-coverage

Your own site · 80×15
<a href="https://agentmods.dev/skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage"><img src="https://agentmods.dev/badge/skills/jaktestowac/awesome-copilot-for-testers/verifying-change-coverage.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 97 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,290 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium MCP Rug Pull · line 52
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 50
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 51
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
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 $0.00097 $0.02290
Opus 5 $0.00048 $0.01145
Sonnet 5 $0.00019 $0.00458
Haiku 4.5 $0.00010 $0.00229

Measured 7d ago against content hash b1d96865ddc3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

verifying-change-coverage 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.

plugins/verifying-change-coverage/skills/verifying-change-coverage/SKILL.md · 156 lines

How it starts

The opening of the file, as written. The whole thing — 156 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verifying Change Coverage

Use this skill to answer one question honestly: were the lines this change introduced actually executed by a test?

Repo-wide coverage cannot answer it. A repo at 84% can merge an untested payment path and stay at 84%, because a big denominator absorbs a small numerator. Diff coverage changes the denominator to the lines you just wrote, which is the only denominator that maps to the risk you just added.

The distinction that runs through this skill: configured is not verified. A test runner in package.json proves the practice exists. Executed lines prove this change was tested. Report which of the two you measured.

When to Use

  • a PR gate needs a coverage signal that cannot be gamed by unrelated tests
  • total coverage is stable but defects keep escaping in new code
  • diff coverage has to be wired into CI for the first time
  • a reviewer needs to know which specific new lines nothing executes
  • an agent wrote tests and someone needs to know whether they exercise the new code
  • coverage numbers are being quoted in a release decision and nobody knows what they measure

Operating Principles

  • Executed lines, not configured tools. The whole point. Say plainly which one you have.
  • No artifact, no verdict. Without a coverage report you have static linkage - "a test file exists that imports this module" - which is weaker evidence and must be labelled as such. Never present it as coverage.
  • Branches matter more than lines on changed code. New code is where new conditionals live. A line hit once with the if never taken is half-tested.
  • Uncovered is a question, not a verdict. Some uncovered lines are fine: logging, type guards, unreachable defaults. The output is a list of uncovered changed lines with a judgement per group, not a percentage with a pass stamp.
  • Coverage proves execution, never correctness. An assertion-free test covers everything and verifies nothing. Pair this with unslop-tests - a diff-coverage gate is exactly the pressure that produces coverage theatre.
  • Escalate by risk, not by count. Three uncovered lines in auth outrank thirty in a formatter.
  • The gate belongs on changed lines only. Demanding a repo-wide floor on a legacy codebase produces a permanently red gate that gets disabled within a month.

Read the full file on GitHub · 156 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 156 lines · 97 tokens per session scan A b1d96865ddc3

Subscribe to this mod's changes

verifying-change-coverage is a skill published in the GitHub repository jaktestowac/awesome-copilot-for-testers (113 stars, last pushed 15d ago), licensed MIT. It adds 97 tokens to every session and 2,290 once invoked, about $0.0005 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 2026-09-03.

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