Hm, you're right, it does say that!

   # Call this system's shell, returns TRUE on 0 exit code
   # THIS IS THE OPPOSITE SENSE OF system()'s RETURN VALUE
      run "cat a b c" or die "cat returned $?";

   # Launch a sub process directly, no shell.  Can't do redirection
   # with this form, it's here to behave like system() with an
   # inverted result.
      $r = run "cat a b c";
[download]

I don't see how run would know that it is being called as run() or die vs. $r = run(). Also, I can't get it to work...

$ perl -wMstrict -MIPC::Run=run -e' my $r = run "pstree -A $$" '
perl---sh---pstree
[download]

Later on the docs say:

run(), start(), and harness() can all take a harness specification as input. A harness specification is either a single string to be passed to the systems' shell

And, on the other hand, the IPC::Run docs don't explicitly say that run [...] doesn't use the shell, although in the code you can find exec { $_[0] } @_;. It's all a bit confusing unfortunately.