Parse and expose stream errors (#2540)

codex-rs/tui/src/chatwidget.rs

@@ -23,6 +23,7 @@ use codex_core::protocol::McpToolCallBeginEvent;
 use codex_core::protocol::McpToolCallEndEvent;
 use codex_core::protocol::Op;
 use codex_core::protocol::PatchApplyBeginEvent;
+use codex_core::protocol::StreamErrorEvent;
 use codex_core::protocol::TaskCompleteEvent;
 use codex_core::protocol::TokenUsage;
 use codex_core::protocol::TurnDiffEvent;
@@ -327,6 +328,12 @@ impl ChatWidget {
     fn on_background_event(&mut self, message: String) {
         debug!("BackgroundEvent: {message}");
     }
+
+    fn on_stream_error(&mut self, message: String) {
+        // Show stream errors in the transcript so users see retry/backoff info.
+        self.add_to_history(history_cell::new_stream_error_event(message));
+        self.mark_needs_redraw();
+    }
     /// Periodic tick to commit at most one queued line to history with a small delay,
     /// animating the output.
     pub(crate) fn on_commit_tick(&mut self) {
@@ -690,6 +697,7 @@ impl ChatWidget {
             EventMsg::BackgroundEvent(BackgroundEventEvent { message }) => {
                 self.on_background_event(message)
             }
+            EventMsg::StreamError(StreamErrorEvent { message }) => self.on_stream_error(message),
         }
         // Coalesce redraws: issue at most one after handling the event
         if self.needs_redraw {