README First-Run Check

The README of a small public React tutorial app says to run yarn && yarn start.

After (skill output, excerpt):
Short answer: no. The one command the README gives, yarn && yarn start, stops at the second half, because the project has no start script.
4 | yarn start | BROKEN | package.json scripts are only dev, build, lint and preview. There is no start.
1 | Install Node.js | MISSING version | .nvmrc says v24. The README gives no version.
Run command: yarn / yarn dev

Point it at a repository. It follows the README like a new user would and checks every step against the repo: versions, scripts, files, environment variables, ports and links. You get each step marked OK, BROKEN, MISSING or UNVERIFIED with evidence, the first-run path a newcomer would actually take, and the README edits that fix it.

1 real-data run on a public MDN tutorial repository (Claude Sonnet). The missing start script, the .nvmrc version and the stale Create React App text were all real.

Tested on a real example before release. The example is shown in the Before and after section above.

How we test, what we do not do, and which assistants we ran it on.

• Read-only by default, so some steps stay UNVERIFIED.
• It cannot see what is not in the repo.
• It proposes README edits; it does not make them.

Works with any assistant that reads SKILL.md skills (Claude, Codex, Gemini CLI, Cursor and others), plus a paste-in prompt version for ChatGPT or any chatbot. A repo to read, or the README and manifests pasted.

1. Run npx skills add proskillpacks/skills in your project and pick this skill. Or copy the readme-first-run-check folder from GitHub (https://github.com/proskillpacks/skills/tree/main/skills/developers/readme-first-run-check).
2. Put the readme-first-run-check folder where your assistant looks for skills. The generic path is .agents/skills/ (or npx skills add from a folder). Tool-specific paths:
   • Claude Code: ~/.claude/skills/ (or .claude/skills/ inside one project)
   • OpenAI Codex, Gemini CLI, Cursor and others: .agents/skills/ or the skills folder their docs name
   • claude.ai: zip the skill folder yourself, then Customize, Skills, the plus button, Create skill, Upload a skill (code execution must be on in Settings, Capabilities)
   • ChatGPT or any chatbot: open the skill's prompt.md, paste it into the chat, then paste your own text or link
   • Steps for each tool, with links to its official docs: how to install Agent Skills
3. Ask for the job in plain words, for example: "Check the getting started steps in the README. Don't install anything.". The skill loads by itself.