Support for dynamic behavior is specified while reducing reliance on JIT compilation and large runtimes; semantic characteristics are selectively attached to types and type members outside source code. A directives document contains human-readable directives in a parsable format for submission to an innovative compiler. The directives specify whether a type T or type member M is required, optional, or prohibited in a runtime environment. Some reference an application, library, assembly, or namespace group, and others reference group components: type, type instantiation, method, method instantiation, field, property, or event. Some directives force a generic instantiation. Some directives indirectly reference a type through a parameter, type parameter, or generic directive. Some directives reference degrees to manage runtime activation of type instances, runtime introspection over types, reflection, and/or runtime or static serialization. Degrees may enable or disable types, instance constructors, property setters, property getters, fields, or all type members. Directives may be composed.