Heat provides an orchestration layer in OpenStack on-top of base compute, network and storage capabilities and allows for defining more advanced patterns on top of those core capabilities. Heat is currently based on Amazon CloudFormation syntax so users have to adopt that specific format. Adding support for another, standardized format such as the OASIS TOSCA standard would allow for also deploying patterns that users have created using that standardized format. TOSCA also provides features for expressing requirements and capabilities of pattern components, that also allow for composing patterns out of (i.e. by re-using) other patterns. Therefore, as part of ongoing refactoring and evolutionary work on Heat, we propose to adopt TOSCA as one supported pattern format, and to align enhancements with concepts found in TOSCA (such as requirements/capabilities).