diff --git a/codex-rs/tui/src/app/session_lifecycle.rs b/codex-rs/tui/src/app/session_lifecycle.rs
index c1d5539f2e..1ab678f622 100644
--- a/codex-rs/tui/src/app/session_lifecycle.rs
+++ b/codex-rs/tui/src/app/session_lifecycle.rs
@@ -16,6 +16,7 @@ use crate::app_server_session::source_agent_path;
 use crate::app_server_session::thread_blocks_direct_input;
 use crate::chatwidget::ThreadInputStateRestoreMode;
 use crate::streaming::commit_tick::CommitTickScope;
+use codex_model_provider_info::OPENAI_PROVIDER_ID;
 use std::collections::HashSet;
 
 #[derive(Clone, Copy)]
@@ -1108,6 +1109,20 @@ impl App {
                 self.enqueue_primary_thread_session(started.session, started.turns)
                     .await?;
                 self.apply_backend_banner_fallback(app_server).await;
+                if let Some(model) = self.harness_overrides.model.as_deref()
+                    && model == self.chat_widget.current_model()
+                    && self.chat_widget.has_chatgpt_account()
+                    && self.chat_widget.config_ref().model_provider_id == OPENAI_PROVIDER_ID
+                    && !self
+                        .model_catalog
+                        .models
+                        .iter()
+                        .any(|preset| preset.model == model)
+                {
+                    self.chat_widget.add_to_history(history_cell::new_visible_warning_event(format!(
+                        "Your ChatGPT model list doesn't include `{model}`. Check the spelling or use /model to choose another model."
+                    )));
+                }
                 if let Some(notice) = self.pending_server_version_notice.take() {
                     self.chat_widget.add_server_version_warning(notice);
                 }
diff --git a/codex-rs/tui/src/app/tests/startup.rs b/codex-rs/tui/src/app/tests/startup.rs
index 04d2c4ea26..7a91a3a2fb 100644
--- a/codex-rs/tui/src/app/tests/startup.rs
+++ b/codex-rs/tui/src/app/tests/startup.rs
@@ -1365,7 +1365,10 @@ async fn known_thread_started_preserves_session_without_reading_unmaterialized_r
 
 #[tokio::test]
 async fn startup_thread_started_submits_queued_startup_input() {
-    let (mut app, _app_event_rx, mut op_rx) = make_test_app_with_channels().await;
+    let (mut app, mut events, mut op_rx) = make_test_app_with_channels().await;
+    set_chatgpt_auth(&mut app.chat_widget);
+    let model = "unlisted-model";
+    app.harness_overrides.model = Some(model.into());
     app.pending_startup_thread_start = true;
     app.chat_widget
         .set_queue_submissions_until_session_configured(/*queue*/ true);
@@ -1384,11 +1387,13 @@ async fn startup_thread_started_submits_queued_startup_input() {
     ))
     .await
     .expect("embedded app server");
-    let thread_id = ThreadId::new();
+    let mut session = test_thread_session(ThreadId::new(), test_path_buf("/tmp/project"));
+    session.model = model.into();
+    session.model_provider_id = "openai".into();
     app.handle_startup_thread_started(
         &mut app_server,
         Ok(AppServerStartedThread {
-            session: test_thread_session(thread_id, test_path_buf("/tmp/project")),
+            session,
             turns: Vec::new(),
             blocks_direct_input: false,
             task_tools_available: false,
@@ -1397,6 +1402,19 @@ async fn startup_thread_started_submits_queued_startup_input() {
     .await
     .expect("startup thread should attach");
 
+    let warnings: Vec<_> = std::iter::from_fn(|| events.try_recv().ok())
+        .filter_map(|event| match event {
+            AppEvent::InsertHistoryCell(cell) if !cell.warning_entries().is_empty() => {
+                Some(lines_to_single_string(&cell.display_lines(/*width*/ 80)))
+            }
+            _ => None,
+        })
+        .collect();
+    insta::assert_snapshot!(warnings.join("\n"), @r"
+    ⚠ Your ChatGPT model list doesn't include `unlisted-model`. Check the spelling
+      or use /model to choose another model.
+    ");
+    assert_eq!(app.chat_widget.current_model(), model);
     match next_user_turn_op(&mut op_rx) {
         Op::UserTurn { items, .. } => assert_eq!(
             items,
diff --git a/codex-rs/tui/src/chatwidget/rate_limits.rs b/codex-rs/tui/src/chatwidget/rate_limits.rs
index a7162b98b9..60c2470d1a 100644
--- a/codex-rs/tui/src/chatwidget/rate_limits.rs
+++ b/codex-rs/tui/src/chatwidget/rate_limits.rs
@@ -393,7 +393,7 @@ impl ChatWidget {
 
             if !warnings.is_empty() {
                 for warning in warnings {
-                    self.add_to_history(history_cell::new_usage_warning_event(warning));
+                    self.add_to_history(history_cell::new_visible_warning_event(warning));
                 }
                 self.request_redraw();
             }
diff --git a/codex-rs/tui/src/history_cell/notices.rs b/codex-rs/tui/src/history_cell/notices.rs
index 9f5e2137f0..7308338aa8 100644
--- a/codex-rs/tui/src/history_cell/notices.rs
+++ b/codex-rs/tui/src/history_cell/notices.rs
@@ -108,7 +108,7 @@ pub(crate) fn new_warning_event(message: String) -> WarningHistoryCell {
     }
 }
 
-pub(crate) fn new_usage_warning_event(message: String) -> WarningHistoryCell {
+pub(crate) fn new_visible_warning_event(message: String) -> WarningHistoryCell {
     WarningHistoryCell {
         visible_in_transcript: true,
         ..new_warning_event(message)
diff --git a/codex-rs/tui/src/history_cell/warnings_tests.rs b/codex-rs/tui/src/history_cell/warnings_tests.rs
index 42cbb002e9..020b3cf981 100644
--- a/codex-rs/tui/src/history_cell/warnings_tests.rs
+++ b/codex-rs/tui/src/history_cell/warnings_tests.rs
@@ -6,12 +6,12 @@ use pretty_assertions::assert_eq;
 #[test]
 fn usage_warnings_render_in_both_transcripts_including_composites() {
     let message = "Only 8% of your 5h limit remains. Run /status for details.";
-    let usage = new_usage_warning_event(message.into());
+    let usage = new_visible_warning_event(message.into());
     let diagnostic = new_warning_event(message.into());
     let composite = CompositeHistoryCell::new(vec![
         Box::new(PlainHistoryCell::new(vec!["Earlier output".into()])),
         Box::new(new_warning_event("Hidden diagnostic".into())),
-        Box::new(new_usage_warning_event(message.into())),
+        Box::new(new_visible_warning_event(message.into())),
     ]);
     assert_eq!(usage.warning_entries(), diagnostic.warning_entries());
     for mode in [HistoryRenderMode::Rich, HistoryRenderMode::Raw] {