On a 3-file sample package it printed 28 findings (18 errors, 10 warnings) from 25 rules, each with file:line and what CRAN expects.

Who it’s for
For R package authors about to submit to CRAN, or answering a rejection email and resubmitting.

What breaks, and when
CRAN mails the submission confirmation to the maintainer address, so a placeholder address ends the submission; a Date over 31 days old draws a NOTE.

What you get
• A scanner Claude runs over DESCRIPTION, NAMESPACE and every .R file - not a…
• 25 rules: Title, Description, License, cre, .9000 Version, Date, Depends…

See it first
The real output of the bundled example is on getreadystack.com/skills/cran-submission-check/ — free, no sign-up, so you see what it finds before you pay.

Install in 30 seconds
Unzip into ~/.claude/skills/, then ask Claude Code: “I’m about to submit my R package to CRAN for the first time. Can you go through DESCRIPTION, NAMESPACE and the R code and tell me what CRAN is likely to reject? Don’t edit anything yet.”. Needs Node 16+.

What it does not do
Reads package files only; it does not run R, R CMD check or the CRAN incoming checks.

FAQ
Q: How is this different from asking Claude without the skill?
A: The skill carries a dated rule table and a scanner that reads every file, so Claude quotes the exact date and line instead of guessing from memory.
Q: How do I get the files?
A: In your Whop library after paying: the lesson “cran-submission-check.zip”.