diff --git a/codex-rs/tui/src/chatwidget/service_tiers.rs b/codex-rs/tui/src/chatwidget/service_tiers.rs
index f23f44dd6..1cdb52f22 100644
--- a/codex-rs/tui/src/chatwidget/service_tiers.rs
+++ b/codex-rs/tui/src/chatwidget/service_tiers.rs
@@ -88,7 +88,7 @@ impl ChatWidget {
                             .into_iter()
                             .map(|tier| ServiceTierCommand {
                                 id: tier.id,
-                                name: tier.name,
+                                name: tier.name.to_lowercase(),
                                 description: tier.description,
                             })
                             .collect()
diff --git a/codex-rs/tui/src/chatwidget/tests/slash_commands.rs b/codex-rs/tui/src/chatwidget/tests/slash_commands.rs
index dc8f2e7cb..4c5319a64 100644
--- a/codex-rs/tui/src/chatwidget/tests/slash_commands.rs
+++ b/codex-rs/tui/src/chatwidget/tests/slash_commands.rs
@@ -62,6 +62,24 @@ fn next_add_to_history_event(rx: &mut tokio::sync::mpsc::UnboundedReceiver<AppEv
     }
 }
 
+#[tokio::test]
+async fn service_tier_commands_lowercase_catalog_names() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("gpt-5.4")).await;
+    let mut preset = get_available_model(&chat, "gpt-5.4");
+    let expected_description = preset.service_tiers[0].description.clone();
+    preset.service_tiers[0].name = "Fast".to_string();
+    chat.model_catalog = std::sync::Arc::new(ModelCatalog::new(vec![preset]));
+
+    assert_eq!(
+        chat.current_model_service_tier_commands(),
+        vec![ServiceTierCommand {
+            id: ServiceTier::Fast.request_value().to_string(),
+            name: "fast".to_string(),
+            description: expected_description,
+        }]
+    );
+}
+
 #[tokio::test]
 async fn slash_compact_eagerly_queues_follow_up_before_turn_start() {
     let (mut chat, mut rx, mut op_rx) = make_chatwidget_manual(/*model_override*/ None).await;