It's a language/compiler/function call stack feature, not existing as far as I know, but it would be awesome - the caller of a function would specify what resources/syscalls could be made, and anything down the chain would be thusly restricted. The library could try to do its phone home stats and it would fail. Couldn't be C or a C type language runtime, or anything that can call to assembly of course. @compute_only decorator. Maybe could be implemented as a sys-call for a thread - thread_capability_remove(F_NETWORK + F_DISK)? Wouldn't be able to schedule any work on any thread in that case, but Go could have pools of threads for coroutines with varying capabilities. Something to put the developer back in charge of the mountain of dependencies we are all forced to manage now.