Specifically, tidy seems to require a trailing "/" on the path for directories; that is,
tidy { tidy_tmp:
path => "/tmp/",
recurse => 1,
matches => [ "jna*.tmp" ],
age => "7d",
backup => false
}

works but:

tidy { tidy_tmp:
path => "/tmp",
recurse => 1,
matches => [ "jna*.tmp" ],
age => "7d",
backup => false
}

doesn't. This seems wrong to me, but may serve some deeper purpose. Since the actual recursion is being done by the file serving code, I'm reluctant to just "fix" it without greater understanding of what's going on.  Anyone have any insights?

Definitely a bug, not a feature.