Permissions

Key	Meaning	Enforced as (WASI)
read [paths]	read files and list folders under these paths	read-only preopened directory
write [paths]	create, change and delete files under these paths	read-write preopened directory
run [patterns]	start these programs	host function: checked, then spawned with a limited environment
net [host:port]	connect to these hosts	host-mediated socket, allow-listed
env [names]	read these environment variables	passed in explicitly
clock, random	the time, random numbers	handles granted or withheld

The subset rule

Set A is a subtype of set B when everything A allows, B allows too.

• write [./src] is smaller than write [.].
• run ["git status"] is smaller than run ["git"].
• net [] is smaller than everything.

A function needing A can be called by anyone who holds B. A call that needs more than the script holds is a compile error, with the line and the fix.