This package provides a key-value interface, \Ccool, on top of xparse's document command parser. Global options control input processing and its expansion. By default, they are set to meet likely requirements, depending on context: the selected language, and which of text and math mode is active. These options can be overridden inline. Polymorphic commands can be generated by parameterizing the keys (for instance, one parameter value for style, another for a property). User input to \Ccool can optionally be serialized. This can useful for typesetting documents sharing the same notation.