Is there any tool available that will scan Pulumi projects and output the policies necessary to run the stack?

This might be what you are after: https://github.com/iann0036/iamlive

But with this tool you have to actually run

pulumi up

as far as I can tell?

Yes, while developing your infra code. After iamlive returns you the matching policy, you can run with this policy for any subsequent environment.

Thanks, I’ll bookmark it, but ideally a sort of “simulation” would have been awesome.