A commanding system for a computer. An input sequence can be received from an input device, and the commanding system can be used to connect the input to an associated action. Commanding can be provided by a plurality of nodes that represent elements of control and application levels. The nodes can be arranged in a hierarchical structure, and each node can include a table of bindings. A service can be attached to one or more of the nodes at run-time to provide additional commanding functionality. For example, a service can modify or supplement the binding entries provided in the table of bindings associated with a given node.