Test a Claude skill on a clean machine before you trust it
A skill works on the machine it was written on. That tells you almost nothing. A container, a fresh install and twenty minutes tells you what a new user will actually hit.
The machine you wrote the skill on is the one place it is guaranteed to work. It has your shell aliases, your installed binaries, your config files and a directory layout the skill quietly assumes. None of that is in the folder you hand someone.
What actually breaks
In our experience the failures are boring and they repeat:
- A binary the script calls that was installed years ago and never declared.
- A path that only exists because of how one person's projects are arranged.
- A config file read without checking whether it is there.
- A tool that exists but is three major versions older than the one it was written against.
- An error that reports success because the script never checked an exit code.
The last one is the worst, because it does not look like a failure. It looks like a clean run that found nothing.
The test
- Start a container from a base image with nothing on it.
- Install the skill exactly the way the README says to, reading the README as you go.
- Run the three examples from the docs, in order, without fixing anything.
- Write down every error verbatim, including the ones you know the answer to.
- Fix the skill, not the container. The container is what the buyer has.
Every error you hit on the clean run is an error a new user hits. That list is the troubleshooting table, already written.
Name every missing dependency at once
A preflight that reports the first missing tool and stops makes someone install it, rerun, hit the second, install that, rerun, hit the third. Check everything up front and print the whole list. It is a few lines and it is the difference between one trip and three.
Do it again after every change
A clean-machine test is only true for the version that was tested. Claude Code moves, dependencies move, and a skill that passed in August can fail in October without anyone touching it. It is a habit, not a milestone.
Every skill in the catalogue installs into a fresh container before it ships, and the errors from that run become its troubleshooting table.
Questions
Why does a skill that works locally fail for someone else?
Because your machine has years of tools installed on it. The skill calls one of them, the call succeeds for you and fails for anyone who does not have it. Nothing in the skill declares the dependency, so nothing warns either of you.
What is the minimum useful clean-machine test?
A container with a fresh image, the skill installed the way a buyer would install it, and the three prompts from the README run in order. Most failures appear in the first two minutes.
Should the skill check for its own dependencies?
Yes, and it should name all of them at once. Failing on the first missing tool, then the second after you install it, then the third, turns one problem into three trips.
Keep reading
Or skip the afternoonand drop one in.
Every skill in the catalogue is a folder you drag into your skills directory. Tested on a clean machine, documented, with the trigger accuracy published.