fix(code): preserve Ctrl+D deletion in non-empty input (#4626)

Ctrl+D now deletes the character to the right in a non-empty prompt and
only exits from an empty prompt.

---

A priority app binding intercepted Ctrl+D before the focused chat text
area could apply its standard delete-right behavior. Delegate Ctrl+D to
the focused text area while a draft exists, and retain quit behavior for
an empty prompt and existing modal flows.

Made by [Open
SWE](https://openswe.vercel.app/agents/9c524bf4-b1c3-5e11-d131-8d5d44be990b)

---------

Co-authored-by: Will Bradley <3030224+wbbradley@users.noreply.github.com>
Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
Co-authored-by: Mason Daugherty <github@mdrxy.com>

libs/code/deepagents_code/app.py

@@ -12671,7 +12671,13 @@ class DeepAgentsApp(App):
         self.set_timer(timeout, lambda: setattr(self, "_clear_input_pending", False))
 
     def action_quit_app(self) -> None:
-        """Handle quit action (Ctrl+D)."""
+        """Handle the Ctrl+D binding.
+
+        Delete-confirm screens and the auth/thread selectors keep their own
+        Ctrl+D behavior. Otherwise, when the chat input is focused and holds a
+        draft, Ctrl+D deletes right of the cursor instead of quitting; the app
+        only exits from an empty (or unfocused) prompt.
+        """
         from deepagents_code.tui.widgets.auth import (
             AuthPromptScreen,
             DeleteCredentialConfirmScreen,
@@ -12696,6 +12702,18 @@ class DeepAgentsApp(App):
                 return
             self._arm_quit_pending("Ctrl+D")
             return
+
+        # Delegate Ctrl+D to the chat input's delete-right when it holds a
+        # draft. Check `self.focused` (the active screen's focused widget), not
+        # `text_area.has_focus`: a draft hidden behind a modal keeps focus but
+        # must not be edited from under it, so Ctrl+D quits in that case.
+        chat_input = self._chat_input
+        if chat_input is not None:
+            text_area = chat_input.input_widget
+            if text_area is not None and self.focused is text_area and chat_input.value:
+                text_area.action_delete_right()
+                return
+
         self.exit()
 
     def exit(

libs/code/deepagents_code/tui/widgets/chat_input.py

@@ -1254,11 +1254,6 @@ class ChatTextArea(TextArea):
             event.stop()
             return
 
-        if event.key == "delete" and self._delete_placeholder_token(backwards=False):
-            event.prevent_default()
-            event.stop()
-            return
-
         # If completion is active, let parent handle navigation keys.
         # Space is included so that slash-command completion can accept the
         # selected suggestion via the same code path as Tab (avoiding a
@@ -1304,6 +1299,11 @@ class ChatTextArea(TextArea):
 
         await super()._on_key(event)
 
+    def action_delete_right(self) -> None:
+        """Delete a bound placeholder atomically or the next character."""
+        if not self._delete_placeholder_token(backwards=False):
+            super().action_delete_right()
+
     def _delete_placeholder_token(self, *, backwards: bool) -> bool:
         """Delete a full placeholder token (image, video, or paste) in one keypress.
 

libs/code/tests/unit_tests/test_app.py

@@ -58,7 +58,7 @@ from deepagents_code.app import (
     _warn_discarded_goal_channels,
 )
 from deepagents_code.event_bus import ExternalEvent
-from deepagents_code.media_utils import ImageData
+from deepagents_code.media_utils import ImageData, VideoData
 from deepagents_code.tui.widgets.ask_user import AskUserTextArea
 from deepagents_code.tui.widgets.chat_input import ChatInput
 from deepagents_code.tui.widgets.goal_review import GoalReviewMenu, GoalReviewResult
@@ -1953,6 +1953,140 @@ class TestAppBindings:
         assert "ctrl+e" not in bindings_by_key
 
 
+class TestCtrlDChatInput:
+    """Test Ctrl+D deletion and quit behavior in the main chat input."""
+
+    async def test_ctrl_d_deletes_right_when_input_has_text(self) -> None:
+        """Ctrl+D should delete right of the cursor without quitting."""
+        app = DeepAgentsApp()
+        async with app.run_test() as pilot:
+            chat_input = app.query_one(ChatInput)
+            text_area = chat_input.input_widget
+            assert text_area is not None
+            text_area.focus()
+            await pilot.press("h", "e", "l", "l", "o")
+            # ctrl+a moves the cursor to the start of the line (not select-all),
+            # so delete-right removes the leading "h".
+            await pilot.press("ctrl+a")
+
+            with patch.object(app, "exit") as exit_mock:
+                await pilot.press("ctrl+d")
+                await pilot.pause()
+
+            assert chat_input.value == "ello"
+            exit_mock.assert_not_called()
+            # A draft swallows the quit rather than half-arming the double-tap.
+            assert app._quit_pending is False
+
+    async def test_ctrl_d_does_not_quit_at_end_of_non_empty_input(self) -> None:
+        """Ctrl+D should be a no-op at the end of a non-empty draft."""
+        app = DeepAgentsApp()
+        async with app.run_test() as pilot:
+            chat_input = app.query_one(ChatInput)
+            text_area = chat_input.input_widget
+            assert text_area is not None
+            text_area.focus()
+            await pilot.press("h", "i")
+
+            with patch.object(app, "exit") as exit_mock:
+                await pilot.press("ctrl+d")
+                await pilot.pause()
+
+            assert chat_input.value == "hi"
+            exit_mock.assert_not_called()
+            assert app._quit_pending is False
+
+    @pytest.mark.parametrize("kind", ["image", "video"])
+    async def test_ctrl_d_deletes_bound_media_placeholder_atomically(
+        self, kind: str
+    ) -> None:
+        """Ctrl+D should delete a bound media placeholder as one token."""
+        app = DeepAgentsApp()
+        async with app.run_test() as pilot:
+            chat_input = app.query_one(ChatInput)
+            text_area = chat_input.input_widget
+            assert text_area is not None
+            if kind == "image":
+                placeholder = app._image_tracker.add_image(
+                    ImageData(base64_data="abc", format="png", placeholder="")
+                )
+            else:
+                placeholder = app._image_tracker.add_video(
+                    VideoData(base64_data="abc", format="mp4", placeholder="")
+                )
+            chat_input.value = placeholder
+            text_area.move_cursor((0, 0))
+            text_area.focus()
+
+            with patch.object(app, "exit") as exit_mock:
+                await pilot.press("ctrl+d")
+                await pilot.pause()
+
+            assert chat_input.value == ""
+            assert app._image_tracker.get_images() == []
+            assert app._image_tracker.get_videos() == []
+            exit_mock.assert_not_called()
+
+    async def test_ctrl_d_deletes_collapsed_paste_placeholder_atomically(self) -> None:
+        """Ctrl+D should preserve collapsed-paste integrity when deleting it."""
+        app = DeepAgentsApp()
+        async with app.run_test() as pilot:
+            chat_input = app.query_one(ChatInput)
+            text_area = chat_input.input_widget
+            assert text_area is not None
+            chat_input.handle_external_paste("p" * 900)
+            text_area.move_cursor((0, 0))
+            assert chat_input.value == "[Pasted text #1]"
+
+            with patch.object(app, "exit") as exit_mock:
+                await pilot.press("ctrl+d")
+                await pilot.pause()
+
+            assert chat_input.value == ""
+            assert 1 in chat_input._pasted_contents
+            exit_mock.assert_not_called()
+
+    async def test_ctrl_d_quits_when_input_is_empty(self) -> None:
+        """Ctrl+D should still quit when the focused chat input is empty."""
+        app = DeepAgentsApp()
+        async with app.run_test() as pilot:
+            chat_input = app.query_one(ChatInput)
+            text_area = chat_input.input_widget
+            assert text_area is not None
+            assert chat_input.value == ""
+            text_area.focus()
+
+            with patch.object(app, "exit") as exit_mock:
+                await pilot.press("ctrl+d")
+                await pilot.pause()
+
+            exit_mock.assert_called_once()
+
+    async def test_ctrl_d_quits_with_non_empty_draft_hidden_by_modal(self) -> None:
+        """Ctrl+D should quit instead of editing a draft hidden behind a modal."""
+        from deepagents_code.tui.widgets.update_available import UpdateAvailableScreen
+
+        app = DeepAgentsApp()
+        async with app.run_test() as pilot:
+            chat_input = app.query_one(ChatInput)
+            text_area = chat_input.input_widget
+            assert text_area is not None
+            text_area.focus()
+            await pilot.press("d", "r", "a", "f", "t", "ctrl+a")
+
+            app.push_screen(UpdateAvailableScreen(_update_entry()))
+            await pilot.pause()
+
+            assert text_area.has_focus
+            assert app.focused is not text_area
+            with patch.object(app, "exit") as exit_mock:
+                await pilot.press("ctrl+d")
+                await pilot.pause()
+
+            assert chat_input.value == "draft"
+            exit_mock.assert_called_once()
+
+
 class TestCtrlCCopySelection:
     """Test Ctrl+C copying a focused input's selection instead of quitting."""