The StackStorm boto3 integration pack provides action integration with boto3.
Make sure you system is configured to use boto3, no configuration necessary for Stackstorm pack. For more information on boto3 configuration follow this link,
http://boto3.readthedocs.io/en/latest/guide/configuration.html
st2 run boto3.action service="ec2" action_name="describe_vpcs" region="us-west-1"
st2 run boto3.action service="ec2" region="us-west-1" action_name="create_vpc" params='{"CidrBlock": "10.0.0.0/16"}'