@startuml
skinparam monochrome true
skinparam packageStyle rectangle
skinparam shadowing false

title System Sequence Diagram (SSD)

autonumber

actor "Collaborator" as collaborator
participant ": System" as System

activate collaborator

    collaborator -> System : requests to record the completion of a task
        activate System

            System --> collaborator : requests task
        deactivate System

        collaborator -> System : provides task
        activate System

            System --> collaborator : displays operation success
        deactivate System

@enduml