The durable-message chapter introduced the durable message and named the four interlocking concepts that together form the operational foundation of coordinated work. The role-playing chapter established the discipline through which participants take on roles and react within them. The message-handler chapter established the role that selects a communication mode and dispatches the message via the selected mode. This chapter establishes the last of the four: the messenger, the role that carries the message along the channel the dispatch named and delivers it to the recipient.
What a Messenger Does
The messenger is a role within the role-playing discipline. A role player who has taken on the messenger role performs the two acts the role-playing chapter established: taking on the role, then reacting. The messenger's defining act is carrying. The role-playing chapter's three foundational reacting capabilities — responding to requests, reacting to current conditions, reporting status — apply to the messenger's work as carrying, monitoring delivery progress, and confirming delivery.
Taking on the Role
The role description tells the messenger to carry, and names the channel along which the carry happens.
A channel is the path the message travels from sender to recipient. A phone line, a postal route, a radio frequency, a courier's hand-to-hand walk. The channel identifier the role description names is what the messenger acts on to carry the message along the right path.
Reacting as the Messenger
Once the role is held, the messenger's work is request-response in nature. The role-playing chapter named three foundational reacting capabilities. Each applies to the messenger's work.
Responding to requests applies as carrying. The runner who takes a folded note from one classroom and walks it to another is carrying. The postal carrier who picks up the day's outgoing mail and walks it along the route is carrying. The radio operator who relays a transmission from the field to headquarters is carrying.
Reacting to current conditions applies as monitoring delivery progress. The messenger observes whether the carry is proceeding as the channel allows, and acts on what observation reveals. A courier who finds the recipient's office closed for the day notes the situation and brings the package back rather than leaving it unattended.
Reporting status applies as confirming delivery. The messenger produces outgoing information about the state of the carry. The postal carrier who scans a package at delivery is confirming. The runner who returns to the sender to say the note was delivered is confirming. The courier who collects a signature at handoff is confirming.
The Foundation
The messenger is one of the four interlocking concepts that together form the operational foundation of coordinated work. The other three — the durable message, the role player, and the message handler — depend on the messenger the way the messenger depends on them. Without the messenger, the handler's dispatch decision cannot be carried to the recipient. Without durable messages, the messenger has nothing to carry. Without role players, the messenger's delivery has no destination. Without the message handler, the messenger has no dispatch to act on.