diff --git a/pbs-client/src/backup_specification.rs b/pbs-client/src/backup_specification.rs
index e44d23d9..e530d197 100644
--- a/pbs-client/src/backup_specification.rs
+++ b/pbs-client/src/backup_specification.rs
@@ -8,8 +8,9 @@ const_regex! {
 }
 
 pub const BACKUP_SOURCE_SCHEMA: Schema = StringSchema::new(
-    "Backup source specification ([<label>:<path>]), the specification \
-    'label' must contain alphanumerics, hyphens and underscores only.",
+    "Backup source specification ([<archive-name>.<type>:<source-path>]), the \
+    'archive-name' must contain alphanumerics, hyphens and underscores only. \
+    The 'type' must be either 'pxar', 'img', 'conf' or 'log'.",
 )
 .format(&ApiStringFormat::Pattern(&BACKUPSPEC_REGEX))
 .schema();
diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
index 18be9d23..44f4f5db 100644
--- a/proxmox-backup-client/src/main.rs
+++ b/proxmox-backup-client/src/main.rs
@@ -631,9 +631,10 @@ fn spawn_catalog_upload(
             backupspec: {
                 type: Array,
                 description:
-                    "List of backup source specifications ([<label.ext>:<path>] ...), the \
-                    specifications 'label' must contain alphanumerics, hyphens and underscores \
-                    only.",
+                    "List of backup source specifications:\
+                    \n\n[<archive-name>.<type>:<source-path>] ...\n\n\
+                    The 'archive-name' must only contain alphanumerics, hyphens and underscores \
+                    while the 'type' must be either 'pxar', 'img', 'conf' or 'log'.",
                 items: {
                     schema: BACKUP_SOURCE_SCHEMA,
                 }