Kevin,
please reconsider. There are scripts (AppleXML for instance) which don't need anything.
My idea is:
Sigil generates legitimate path to tmp and passes it to script,
script creates (or not) tmp according to path, does its thing and exits,
Sigil checks if tmp exists, does its things, deletes tmp and goes on.
Unnecessary disc activities (hate them!) avoided
.
Or do I miss something? As all belongs to Sigil premissions should be ok?
ps: bugs, bugs and bugs again... f...