it already has one - https://github.com/chr15m/runprompt/blob/main/runprompt#L1

If you curl/wget a script, you still need to chmod +x it. Git doesn't have this issue as it retains the file metadata.

I'm assuming the intent was to as if the *.prompt files could have a shebang line.

   #!/bin/env runprompt
   ---
   .frontmatter...
   ---
   
   The prompt.