diff --git a/lib/Percona/WebAPI/Resource/Agent.pm b/lib/Percona/WebAPI/Resource/Agent.pm
index 57c7efcb..d5112645 100644
--- a/lib/Percona/WebAPI/Resource/Agent.pm
+++ b/lib/Percona/WebAPI/Resource/Agent.pm
@@ -32,7 +32,7 @@ has 'username' => (
    is       => 'rw',
    isa      => 'Str',
    required => 1,
-   default  => $ENV{USER} || $ENV{LOGNAME},
+   default  => sub { return $ENV{USER} || $ENV{LOGNAME} },
 );
 
 has 'hostname' => (