create-verification-skill

create-verification-skill is a skill for Claude Code, Codex from michael-denyer/pstack-claude. It costs 64 tokens per session (1,382 once invoked), scanned A, a copy of create-verification-skill, MIT.

A guide for generating a project-specific verification skill that operates an application like a real user and records evidence that it works.

In plain words
What is it for?
Inspecting a repository to determine how its app runs, then defining checks that launch it, exercise important behavior, and capture results for later agents.
Why use it?
It creates a repeatable way to test a web app, command-line tool, desktop app, API, mobile app, or library when the project lacks a reliable verification process.

Skill for Claude CodeCodex

Part of the pstack plugin — 52 skills, 2 agents, 1 hook shipped together

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.

agentmods
npx agentmods add skills/michael-denyer/pstack-claude/create-verification-skill
Any agent
npx skills add michael-denyer/pstack-claude --skill create-verification-skill
Clone the repo
git clone --depth 1 https://github.com/michael-denyer/pstack-claude

Made for: Claude Code, Codex.

Or install pstack, the plugin that ships this one along with the rest of its 52 skills, 2 agents, 1 hook.

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 create-verification-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/michael-denyer/pstack-claude/create-verification-skill.svg)](https://agentmods.dev/skills/michael-denyer/pstack-claude/create-verification-skill)
Your own site
<a href="https://agentmods.dev/skills/michael-denyer/pstack-claude/create-verification-skill"><img src="https://agentmods.dev/badge/skills/michael-denyer/pstack-claude/create-verification-skill.svg" alt="Measured on agentmods" height="20"></a>
Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,382 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin 92% copy Near-identical to another mod 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 $0.00064 $0.01382
Opus 5 $0.00032 $0.00691
Sonnet 5 $0.00013 $0.00276
Haiku 4.5 $0.00006 $0.00138

Measured today against content hash b34719949328, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-verification-skill scanned grade A with 1 finding 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 today.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- **Drive:** how can an agent interact with it programmatically? Existing harnesses first — Playwright/Cypress specs, expect scripts, PTY helpers, curl-able endpoints, a debug port. Only then pick a generic recipe: brows
Origin

This is a copy

92% identical to create-verification-skill — 14 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/pstack/skills/create-verification-skill/SKILL.md · 47 lines

How it starts

The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create a verification skill

Every serious project needs a scripted way to drive the real app and prove behavior: launch it, exercise a feature the way a user would, and capture evidence. This skill generates that as a project-local skill (.claude/skills/verify-<app>/) tailored to the repo. You write the generator's output for the next agent, not for a human: it will be read cold, mid-task, by an agent that has never seen the app.

Platform note. The generated skill lands under .claude/skills/verify-<app>/ on Claude Code. On Codex, write it to Codex's project-skill location instead. The app-driving harness is platform-neutral; resolve Codex tool names via codex-tools.md.

1. Interview the repo, not the user

Answer these from the codebase and only ask the user what you cannot observe:

  • Surface: what does a user actually touch? A web UI, a CLI/TUI, a desktop app, an API, a mobile app, a library? A repo can have several; pick the primary one and note the rest.
  • Run: how does the app start locally? Prefer the repo's own documented dev command (package scripts, Makefile, README quickstart). Note ports, env vars, seed data, auth.
  • Drive: how can an agent interact with it programmatically? Existing harnesses first — Playwright/Cypress specs, expect scripts, PTY helpers, curl-able endpoints, a debug port. Only then pick a generic recipe: browser/CDP for web and Electron, a tmux/PTY harness for CLI/TUI, plain HTTP for services.
  • Observe: what evidence can be captured? Screenshots, terminal transcripts, response bodies, logs, exit codes, DB state.
  • Isolate: can two instances run side by side (ports, data dirs, profiles)? If not, say so in the generated skill: refusing to double-drive a shared instance beats corrupting the user's session.

If the checkout doesn't build or start as-is, fix that first (or report it precisely) before generating; a skill written against a broken base teaches wrong steps. When an irrelevant missing asset blocks startup (a static dir the API never serves, a sample config), the generated skill may create it, clearly marked as verification scaffolding, and remove it in cleanup.

Read the full file on GitHub · 47 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. today Changed b34719949328
  2. 4d ago First seen · 47 lines · 64 tokens per session scan A 61e85333067e

Subscribe to this mod's changes

create-verification-skill is a skill published in the GitHub repository michael-denyer/pstack-claude (195 stars, last pushed 2d ago), licensed MIT. It adds 64 tokens to every session and 1,382 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 92% identical to create-verification-skill, differing in 14 lines, and is treated as a copy.

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