sandbox:safe_meta(+Goal, -Called) is semidet[multifile, library(aggregate)]

Declare the aggregate meta-calls safe. This cannot be proven due to the manipulations of the argument Goal.

safe_meta(+Goal, -Called:list(callable)) is semidet[multifile, library(sandbox)]

Hook. True if Goal is a meta-predicate that is considered safe iff all elements in Called are safe.

sandbox:safe_meta(+Goal, -Called) is semidet[multifile, library(pengines)]

Declare the pengine meta-predicates as safe. Note that the pengine calling predicates are safe because the safety is guaranteed by the recieving pengine.