tui: separator above final agent message (#4324)

Adds a separator line before the final agent message

<img width="1011" height="884" alt="Screenshot 2025-09-26 at 4 55 01 PM"
src="https://github.com/user-attachments/assets/7c91adbf-6035-4578-8b88-a6921f11bcbc"
/>

codex-rs/tui/src/bottom_pane/mod.rs

@@ -102,6 +102,10 @@ impl BottomPane {
         }
     }
 
+    pub fn status_widget(&self) -> Option<&StatusIndicatorWidget> {
+        self.status.as_ref()
+    }
+
     fn active_view(&self) -> Option<&dyn BottomPaneView> {
         self.view_stack.last().map(std::convert::AsRef::as_ref)
     }

codex-rs/tui/src/chatwidget.rs

@@ -254,6 +254,8 @@ pub(crate) struct ChatWidget {
     // List of ghost commits corresponding to each turn.
     ghost_snapshots: Vec<GhostCommit>,
     ghost_snapshots_disabled: bool,
+    // Whether to add a final message separator after the last message
+    needs_final_message_separator: bool,
 }
 
 struct UserMessage {
@@ -648,6 +650,14 @@ impl ChatWidget {
         self.flush_active_cell();
 
         if self.stream_controller.is_none() {
+            if self.needs_final_message_separator {
+                let elapsed_seconds = self
+                    .bottom_pane
+                    .status_widget()
+                    .map(super::status_indicator_widget::StatusIndicatorWidget::elapsed_seconds);
+                self.add_to_history(history_cell::FinalMessageSeparator::new(elapsed_seconds));
+                self.needs_final_message_separator = false;
+            }
             self.stream_controller = Some(StreamController::new(self.config.clone()));
         }
         if let Some(controller) = self.stream_controller.as_mut()
@@ -901,6 +911,7 @@ impl ChatWidget {
             is_review_mode: false,
             ghost_snapshots: Vec::new(),
             ghost_snapshots_disabled: true,
+            needs_final_message_separator: false,
         }
     }
 
@@ -962,6 +973,7 @@ impl ChatWidget {
             is_review_mode: false,
             ghost_snapshots: Vec::new(),
             ghost_snapshots_disabled: true,
+            needs_final_message_separator: false,
         }
     }
 
@@ -1188,6 +1200,7 @@ impl ChatWidget {
 
     fn flush_active_cell(&mut self) {
         if let Some(active) = self.active_cell.take() {
+            self.needs_final_message_separator = true;
             self.app_event_tx.send(AppEvent::InsertHistoryCell(active));
         }
     }
@@ -1200,6 +1213,7 @@ impl ChatWidget {
         if !cell.display_lines(u16::MAX).is_empty() {
             // Only break exec grouping if the cell renders visible lines.
             self.flush_active_cell();
+            self.needs_final_message_separator = true;
         }
         self.app_event_tx.send(AppEvent::InsertHistoryCell(cell));
     }
@@ -1241,6 +1255,7 @@ impl ChatWidget {
         if !text.is_empty() {
             self.add_to_history(history_cell::new_user_prompt(text));
         }
+        self.needs_final_message_separator = false;
     }
 
     fn capture_ghost_snapshot(&mut self) {

codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__binary_size_ideal_response.snap

@@ -1,5 +1,6 @@
 ---
 source: tui/src/chatwidget/tests.rs
+assertion_line: 1152
 expression: "lines[start_idx..].join(\"\\n\")"
 ---
 • I need to check the codex-rs repository to explain why the project's binaries
@@ -9,6 +10,8 @@ expression: "lines[start_idx..].join(\"\\n\")"
   is set up. I should look into the Cargo.toml file to confirm features and
   profiles without needing to edit any code. Let's get started on this!
 
+─ Worked for 0s ────────────────────────────────────────────────────────────────
+
 • I’m going to scan the workspace and Cargo manifests to see build profiles and
   dependencies that impact binary size. Then I’ll summarize the main causes.
 
@@ -110,6 +113,8 @@ expression: "lines[start_idx..].join(\"\\n\")"
   "Main Causes" and "Build-Mode Notes." I can also include brief suggestions for
   reducing size, but I want to stay focused on answering the user's question.
 
+─ Worked for 0s ────────────────────────────────────────────────────────────────
+
 • Here’s what’s driving size in this workspace’s binaries.
 
   Main Causes

codex-rs/tui/src/chatwidget/tests.rs

@@ -340,6 +340,7 @@ fn make_chatwidget_manual() -> (
         is_review_mode: false,
         ghost_snapshots: Vec::new(),
         ghost_snapshots_disabled: false,
+        needs_final_message_separator: false,
     };
     (widget, rx, op_rx)
 }

codex-rs/tui/src/history_cell.rs

@@ -1090,6 +1090,40 @@ pub(crate) fn new_reasoning_summary_block(
     Box::new(new_reasoning_block(full_reasoning_buffer, config))
 }
 
+#[derive(Debug)]
+pub struct FinalMessageSeparator {
+    elapsed_seconds: Option<u64>,
+}
+impl FinalMessageSeparator {
+    pub(crate) fn new(elapsed_seconds: Option<u64>) -> Self {
+        Self { elapsed_seconds }
+    }
+}
+impl HistoryCell for FinalMessageSeparator {
+    fn display_lines(&self, width: u16) -> Vec<Line<'static>> {
+        let elapsed_seconds = self
+            .elapsed_seconds
+            .map(super::status_indicator_widget::fmt_elapsed_compact);
+        if let Some(elapsed_seconds) = elapsed_seconds {
+            let worked_for = format!("─ Worked for {elapsed_seconds} ─");
+            let worked_for_width = worked_for.width();
+            vec![
+                Line::from_iter([
+                    worked_for,
+                    "─".repeat((width as usize).saturating_sub(worked_for_width)),
+                ])
+                .dim(),
+            ]
+        } else {
+            vec![Line::from_iter(["─".repeat(width as usize).dim()])]
+        }
+    }
+
+    fn transcript_lines(&self) -> Vec<Line<'static>> {
+        vec![]
+    }
+}
+
 fn format_mcp_invocation<'a>(invocation: McpInvocation) -> Line<'a> {
     let args_str = invocation
         .arguments

codex-rs/tui/src/status_indicator_widget.rs

@@ -34,7 +34,7 @@ pub(crate) struct StatusIndicatorWidget {
 
 // Format elapsed seconds into a compact human-friendly form used by the status line.
 // Examples: 0s, 59s, 1m 00s, 59m 59s, 1h 00m 00s, 2h 03m 09s
-fn fmt_elapsed_compact(elapsed_secs: u64) -> String {
+pub fn fmt_elapsed_compact(elapsed_secs: u64) -> String {
     if elapsed_secs < 60 {
         return format!("{elapsed_secs}s");
     }
@@ -142,7 +142,7 @@ impl StatusIndicatorWidget {
         elapsed.as_secs()
     }
 
-    fn elapsed_seconds(&self) -> u64 {
+    pub fn elapsed_seconds(&self) -> u64 {
         self.elapsed_seconds_at(Instant::now())
     }
 }