This document discusses how software-defined networking (SDN) can be used as a set of tools to program and control MPLS networks in a more flexible way. It describes several SDN components that could be used together, such as BGP-LS to extract topology information, stateful path computation elements (PCEs) to control services, and a proposed interface to the routing system (IRS) to programmatically control routers. The document argues that combining existing protocols like these with a centralized control plane separated from the data plane could enable new services and more programmatic control over MPLS networks.