We propose mobile agents for enabling interoperability and global intelligence with smart objects in the Internet of Things, with heterogeneous low-power resource-constrained devices where the systems span over disparate networks and protocols. As the Internet of Things systems are in continuous transition, requiring software adaptation and system evolution, an adaptable composition is presented for the mobile agents. The composition complies with the Representational State Transfer principles, which are then utilized in agent creation, migration and control. Moreover, the smart objects’ resources, their capabilities, their information and provided services are exposed to the Web for human-machine interactions. We consider the requirements for enabling mobile agents in the Internet of Things from multiple perspectives: the smart object, the mobile agent and the system. We present interfaces for smart object internal architecture to enable mobile agents and to enable their interactions. An application programming interface is suggested with a system reference architecture, which includes components in the information infrastructure. Lastly, an evaluation metrics for the mobile agent composition and for the smart objects’ resource utilization are suggested, taking the different types of system resources and their utilization into account, assisting in the system, application, smart object and the mobile agent design.