feat(tui): Refresh git branch marker on transcript activity

codex-rs/tui/docs.md

@@ -573,6 +573,15 @@ The ACP protocol sets CWD at session creation and it is immutable. However, when
 │ ChatWidget        │ ─────────────────────────▶│ BottomPane │
 └───────────────────┘                          └────────────┘
 ```
+*Transcript Activity Refresh:*
+
+In addition to CWD tracking, system info refreshes on transcript activity to catch branch changes that occur outside the agent's operations (e.g., user switching branches in another terminal):
+
+- **User message submission**: `submit_user_message()` sends `RefreshSystemInfoForDirectory(config.cwd)` when the user submits a new message
+- **Task completion**: `on_task_complete()` sends `RefreshSystemInfoForDirectory(config.cwd)` when an agent turn finishes
+
+These triggers use the session CWD (not the effective CWD from tracking) since they detect changes made by the user rather than by agent operations.
+
 *Git Worktree Detection:*
 
 `SystemInfo` includes an `is_worktree: bool` field that indicates whether the current directory is a git worktree (not the main repository). Detection works by comparing `git rev-parse --git-common-dir` with `--git-dir` - in a worktree, these paths differ.

codex-rs/tui/src/chatwidget.rs

@@ -619,6 +619,13 @@ impl ChatWidget {
         self.last_unified_wait = None;
         self.request_redraw();
 
+        // Refresh system info (including git branch) on task completion.
+        // This catches any branch changes that occurred during the agent's turn.
+        self.app_event_tx
+            .send(AppEvent::RefreshSystemInfoForDirectory(
+                self.config.cwd.clone(),
+            ));
+
         // If there is a queued user message, send exactly one now to begin the next turn.
         self.maybe_send_next_queued_input();
         // Emit a notification when the turn completes (suppressed if focused).
@@ -1996,6 +2003,14 @@ impl ChatWidget {
         // Track user message for session statistics
         self.session_stats.record_user_message();
 
+        // Refresh system info (including git branch) on user message submission.
+        // This catches branch changes that happened between interactions
+        // (e.g., user switched branches in another terminal).
+        self.app_event_tx
+            .send(AppEvent::RefreshSystemInfoForDirectory(
+                self.config.cwd.clone(),
+            ));
+
         // Check if there's a pending agent switch - if so, send the message through
         // the App to trigger the switch first
         if let Some(pending) = self.pending_agent.take() {

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

@@ -3799,3 +3799,60 @@ mod strip_ansi_codes_tests {
         assert_eq!(strip_ansi_codes("\x1b[2Jtext\x1b[H"), "text");
     }
 }
+
+/// Submitting a user message triggers a system info refresh to update the branch marker.
+/// This ensures the branch marker in the footer is updated on every transcript activity,
+/// catching branch changes that happened between interactions (e.g., user switched
+/// branches in another terminal).
+#[test]
+fn user_message_submission_triggers_system_info_refresh() {
+    let (mut chat, mut rx, _op_rx) = make_chatwidget_manual();
+
+    // Drain any events from widget construction
+    drain_refresh_system_info_events(&mut rx);
+
+    // Submit a user message
+    chat.bottom_pane
+        .set_composer_text("test message".to_string());
+    chat.handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
+
+    // Verify that RefreshSystemInfoForDirectory was sent
+    let refresh_dirs = drain_refresh_system_info_events(&mut rx);
+    assert!(
+        !refresh_dirs.is_empty(),
+        "expected RefreshSystemInfoForDirectory event after user message submission"
+    );
+}
+
+/// Task completion triggers a system info refresh to update the branch marker.
+/// This ensures any branch changes that occurred during the agent's turn are reflected.
+#[test]
+fn task_complete_triggers_system_info_refresh() {
+    let (mut chat, mut rx, _op_rx) = make_chatwidget_manual();
+
+    // Start a task
+    chat.handle_codex_event(Event {
+        id: "task-start".into(),
+        msg: EventMsg::TaskStarted(TaskStartedEvent {
+            model_context_window: None,
+        }),
+    });
+
+    // Drain any events from task start
+    drain_refresh_system_info_events(&mut rx);
+
+    // Complete the task
+    chat.handle_codex_event(Event {
+        id: "task-complete".into(),
+        msg: EventMsg::TaskComplete(TaskCompleteEvent {
+            last_agent_message: Some("Done".to_string()),
+        }),
+    });
+
+    // Verify that RefreshSystemInfoForDirectory was sent
+    let refresh_dirs = drain_refresh_system_info_events(&mut rx);
+    assert!(
+        !refresh_dirs.is_empty(),
+        "expected RefreshSystemInfoForDirectory event after task completion"
+    );
+}