diff --git a/zebrad/src/commands/start.rs b/zebrad/src/commands/start.rs
index 39817b3b7..808f3a3e6 100644
--- a/zebrad/src/commands/start.rs
+++ b/zebrad/src/commands/start.rs
@@ -1,4 +1,21 @@
 //! `start` subcommand - entry point for starting a zebra node
+//!
+//!  ## Application Structure
+//!
+//!  A zebra node consists of the following services and tasks:
+//!
+//!  * Network Service
+//!    * primary interface to the node
+//!    * handles all external network requests for the zcash protocol
+//!    * provides an interface to the rest of the network for other services and
+//!    tasks running within this node
+//!  * Consensus Service
+//!    * handles all validation logic for the node
+//!    * verifies blocks using zebra-chain and zebra-script, then stores verified
+//!    blocks in zebra-state
+//!  * Sync Task
+//!    * This task runs in the background and continouously queries the network for
+//!    new blocks to be verified and added to the local state
 use crate::config::ZebradConfig;
 use crate::{components::tokio::TokioComponent, prelude::*};
 use abscissa_core::{config, Command, FrameworkError, Options, Runnable};