This works now but could at some point fail with a shell error: argument list too long. Using xargs is one option and maybe markdown-lint has some other built-in function.

If a file has spaces that would also be problematic.

Same as before, you could just add xargs in front of pnpm here. You could use null instead of newline (tr , ’\0’, xargs -0) for additional safety. For ultimate safety, store files in env via yaml and echo the env in addition to null handling and all bases are covered.

I like this - seems like it might make it easier to debug issues later too

something like a commented out debug line that writes the env contents into a file? is that possible/useful?

I'm not sure what it would specifically look like or if it's a cat or echo (printf?) thing, but something like:

cat <<< "$changed-files" > "list-changed-files.txt"

@mafredri I am leaving the suggestions here out of this PR. I need to learn the risks here and can address them in a follow-up PR. I also welcome you taking a jab at this.

Do our replacement commands obey .gitignore now that we don't use prettier/.prettierignore?

most of the formatting is done by biome and it supports .gitignore. I need to configure it though.
See: https://biomejs.dev/reference/configuration/#vcsuseignorefile