High-level specifications are used by researchers to describe and provide autonomy for complex robotics tasks that require planning and coordination between robots and the environment in which they operate. Examples of complex robotic tasks that can be described by high-level specifications include patrolling a large area, searching an abandoned building, and guiding people through unknown environments. These tasks may contain time constraints and require response by the robots in the system to external environment events such as alarms or other signals. This dissertation focuses on describing and satisfying timed high-level specifications for single and multi-robot systems. First, to describe these high-level specifications we propose a new specification language named Event-based Signal Temporal Logic (STL) which encodes tasks with timing constraints that are reactive to uncontrolled environment events. Next, to satisfy these tasks we propose a control synthesis framework for single and multi-robot systems. Current solutions for satisfying similar tasks require solving computationally expensive problems and place assumptions on the environment and adversaries present where the robots operate. This approach to Event-based STL tasks combines automata based synthesis and Control Barrier Functions to produce robot behaviors that satisfy the specification when possible given the state of the environment. This reduces the computational complexity allowing for a higher sampling rate which is necessary to satisfy reactive tasks. During an execution of a specification, the system gives automatically generated feedback in the form of pre-failure warnings to users. This feedback gives insight as to why a specification may be violated in the future. In current approaches, it is often not clear why or what may cause a robotic system to not be able to satisfy a task as intended. This becomes more problematic for complex systems that contain several different types of constraints and tasks that must be satisfied. The feedback and pre-failure warnings described in this dissertation aim to increase the ability of operators to troubleshoot and understand issues that may cause a specification to be violated. Using pre-failure warnings, and the work described in this dissertation, a user may modify currently executing Event-based STL specifications. Allowing modifications to a specification gives the user the opportunity to change the desired behavior of a task in response to potential future violations, changes to the environment, or user-defined task changes. In cases where a modification may not result in the desired behavior of the system, we provide feedback to the user and suggest alternative modifications possible under the defined grammar. The effectiveness of this new specification language, control synthesis and modification framework, and automated feedback generation are demonstrated through simulated and physical executions of single and multi-robot systems satisfying Event-based STL specifications in complex environments.