The four checks
1. Work on a system you did not write
Not a tutorial, not your own greenfield repo. Code that existed before you touched it, with your change visible in it.
1 · none exists 5 · a stranger can open it today
2. A check a stranger can run
A test, an eval, or a written checklist that would catch your change being wrong, runnable by someone who never met you.
1 · "trust me, it works" 5 · run this command, see for yourself
3. A defense, out loud
You have explained a real change to another person, answered why it is safe, and survived the follow-up questions.
1 · never 5 · recorded, with hostile questions
4. A public trail
A stranger who searches you finds the work above in under a minute: a profile line, a post, a PR with your name on it.
1 · nothing points at real work 5 · one click from my name
Your name, for the card
All four need a number. An honest 1 beats a hopeful blank.