  Our goal is to solve both problems of adverse selection and moral hazard for
multi-agent projects. In our model, each selected agent can work according to
his private "capability tree". This means a process involving hidden actions,
hidden chance events and hidden costs in a dynamic manner, and providing
contractible consequences which are affecting each other's working process and
the outcome of the project. We will construct a mechanism that induces truthful
revelation of the agents' capability trees and chance events and to follow the
instructions about their hidden decisions. This enables the planner to select
the optimal subset of agents and obtain the efficient joint execution. We will
construct another mechanism that is collusion-resistant but implements an only
approximately efficient outcome. The latter mechanism is widely applicable, and
the major application details will be elaborated.
