diff --git a/agent/server/main.go b/agent/server/main.go
index a664052..2c40eaa 100644
--- a/agent/server/main.go
+++ b/agent/server/main.go
@@ -14,6 +14,8 @@ import (
 	"go.uber.org/zap"
 )
 
+// main is executed in an (isolated) agent docker container to receive grading requests
+// from users and execute them.
 func main() {
 	var bindIP, bindPort string
 	cfg := zap.NewDevelopmentConfig()
diff --git a/agent/user/main.go b/agent/user/main.go
index 339d4b1..e07bbef 100644
--- a/agent/user/main.go
+++ b/agent/user/main.go
@@ -13,6 +13,7 @@ import (
 	"go.uber.org/zap"
 )
 
+// main is executes in the user docker container to submit a solution to the grader.
 func main() {
 	cfg := zap.NewDevelopmentConfig()