Verify Non Functional

Q: What is a Claude Code skill and how does the Verify Non Functional skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Verify Non Functional is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Security category. Learn more at https://claudskills.com/learn/what-is-skill-md/.

Category: Security · Sub-category: security-misc · Last updated: 2026-06-15

Use when the build implies quality beyond "it works" — sweep the non-functional surface: performance under load, accessibility, the obvious security holes, and reliability/recovery. Find the obvious failures; escalate the deep ones.

From the source SKILL.md

A feature can pass every functional test and still fail the user: it's correct but takes nine seconds, unusable with a keyboard, leaks one user's data to another, or loses everything on a crash. Functional testing answers "does it do the thing?"; non-functional testing answers "is it fast, safe, usable, and reliable enough to ship?" — a class of defect unit tests almost never catch. Sweep the dimensions this build implies (it won't be all of them).

What this skill does

Verify Non Functional is a community-contributed Claude Code skill in the security-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/verify-non-functional/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when the build implies quality beyond "it works" — sweep the non-functional surface: performance under load, accessibility, the obvious security holes, and reliability/recovery. Find the obvious failures; escalate the deep ones.

Who uses this skill

The Verify Non Functional Claude Code skill is built for security engineers, penetration testers, DevSecOps practitioners, and development teams hardening codebases and infrastructure. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 117,000+ 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/verify-non-functional
curl -L https://claudskills.com/skills/verify-non-functional/SKILL.md \
  -o ~/.claude/skills/verify-non-functional/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/verify-non-functional/. Claude Code auto-discovers it on next session.

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

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

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

Frequently asked questions

How do I install the Verify Non Functional Claude Code skill?

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

What does the Verify Non Functional skill do?

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.

When should I use the Verify Non Functional skill?

Use Verify Non Functional when your Claude Code task falls under the Security category — specifically in the security misc area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Verify Non Functional" or describe the task and let Claude pick). Browse related skills at /category/security/.

What is a Claude Code skill and how does the Verify Non Functional skill fit in?

A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Verify Non Functional is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Security category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Source: https://github.com/wastedcode/truecast/blob/HEAD/personas/qa/core/skills/verify-non-functional/SKILL.md
License: MIT
Author: wastedcode

Cite this skill

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

APA

wastedcode. (2026). Verify Non Functional [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/verify-non-functional/

BibTeX

@misc{verify-non-functional-2026,
  author    = {wastedcode},
  title     = {Verify Non Functional [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/verify-non-functional/}
}

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