fix(shell): let Alt+Backspace delete a word inside modal text input

CHANGELOG.md

@@ -11,6 +11,7 @@ Only write entries that are worth mentioning to users.
 
 ## Unreleased
 
+- Shell: Fix Alt+Backspace not deleting a word inside modal text input (e.g. the `/btw` panel) — the global escape key binding was registered with `eager=True`, which swallowed the leading `escape` of the `escape,backspace` sequence before prompt_toolkit could match the emacs `backward-kill-word` binding; the eager flag is now disabled while a modal text input delegate is active so multi-key sequences resolve normally (fixes #1744)
 - Shell: Add `/btw` side question command — ask a quick question during streaming without interrupting the main conversation; uses the same system prompt and tool definitions for prompt cache alignment; responses display in a scrollable modal panel with streaming support
 - Shell: Redesign bottom dynamic area — split the monolithic `visualize.py` (1865 lines) into a modular package (`visualize/`) with dedicated modules for input routing, interactive prompts, approval/question panels, and btw modal; unify input semantics with `classify_input()` for consistent command routing
 - Shell: Add queue and steer dual-channel input during streaming — Enter queues messages for delivery after the current turn; Ctrl+S injects messages immediately into the running turn's context; queued messages display in the prompt area with count indicator and can be recalled with ↑

docs/en/release-notes/changelog.md

@@ -4,6 +4,7 @@ This page documents the changes in each Kimi Code CLI release.
 
 ## Unreleased
 
+- Shell: Fix Alt+Backspace not deleting a word inside modal text input (e.g. the `/btw` panel) — the global escape key binding was registered with `eager=True`, which swallowed the leading `escape` of the `escape,backspace` sequence before prompt_toolkit could match the emacs `backward-kill-word` binding; the eager flag is now disabled while a modal text input delegate is active so multi-key sequences resolve normally (fixes #1744)
 - Shell: Add `/btw` side question command — ask a quick question during streaming without interrupting the main conversation; uses the same system prompt and tool definitions for prompt cache alignment; responses display in a scrollable modal panel with streaming support
 - Shell: Redesign bottom dynamic area — split the monolithic `visualize.py` (1865 lines) into a modular package (`visualize/`) with dedicated modules for input routing, interactive prompts, approval/question panels, and btw modal; unify input semantics with `classify_input()` for consistent command routing
 - Shell: Add queue and steer dual-channel input during streaming — Enter queues messages for delivery after the current turn; Ctrl+S injects messages immediately into the running turn's context; queued messages display in the prompt area with count indicator and can be recalled with ↑

docs/zh/release-notes/changelog.md

@@ -4,6 +4,7 @@
 
 ## 未发布
 
+- Shell：修复模态文本输入（如 `/btw` 面板）中 Alt+Backspace 无法按词删除的问题——全局 escape 键绑定注册时使用了 `eager=True`，会在 prompt_toolkit 匹配 emacs `backward-kill-word` 之前吞掉 `escape,backspace` 序列里的 escape；现在当模态文本输入 delegate 处于活跃状态时禁用 eager 标志，多键序列恢复正常解析（修复 #1744）
 - Shell：新增 `/btw` 侧问命令——在 streaming 期间提出快速问题，不打断主对话；使用相同的系统提示词和工具定义以对齐 Prompt 缓存；响应在可滚动的模态面板中显示，支持流式输出
 - Shell：重新设计底部动态区——将单体 `visualize.py`（1865 行）拆分为模块化包（`visualize/`），包含输入路由、交互式提示、审批/提问面板和 btw 模态面板等独立模块；通过 `classify_input()` 统一输入语义，实现一致的命令路由
 - Shell：新增 streaming 期间的排队和 steer 双通道输入——Enter 将消息排队，在当前轮次结束后发送；Ctrl+S 将消息立即注入到正在运行的轮次上下文中；排队消息在提示区域显示计数指示器，可通过 ↑ 键召回编辑

src/kimi_cli/ui/shell/prompt.py

@@ -1369,9 +1369,16 @@ def _(event: KeyPressEvent) -> None:
         def _(event: KeyPressEvent) -> None:
             self._handle_running_prompt_key("c-d", event)
 
+        # `eager=True` ensures a plain Escape closes the modal immediately, but
+        # prompt_toolkit's eager matching short-circuits longer sequences such as
+        # `escape backspace` (Alt+Backspace → backward-kill-word). When the modal
+        # accepts text input, drop eager so the default Alt+X emacs bindings
+        # (backward-kill-word, backward-word, etc.) work against the buffer
+        # (fixes #1744). The standalone `escape` binding still fires when no
+        # longer sequence arrives, preserving the Escape-to-cancel behaviour.
         @_kb.add(
             "escape",
-            eager=True,
+            eager=Condition(lambda: self._active_ui_state() != PromptUIState.MODAL_TEXT_INPUT),
             filter=Condition(lambda: self._should_handle_running_prompt_key("escape")),
         )
         def _(event: KeyPressEvent) -> None:

tests/ui_and_conv/test_modal_lifecycle.py

@@ -1272,3 +1272,88 @@ async def test_clear_active_approval_sink_requeues_pending_requests(
     shell._pending_approval_requests.clear()  # type: ignore[attr-defined]
     shell._clear_active_view()  # type: ignore[attr-defined]
     assert len(shell._pending_approval_requests) == 0  # type: ignore[attr-defined]
+
+
+# ---------------------------------------------------------------------------
+# CustomPromptSession._active_ui_state — drives the escape key eager filter
+# that fixes Alt+Backspace inside text-input modals (#1744).
+# ---------------------------------------------------------------------------
+
+
+def _make_prompt_session_stub(delegate: object | None):
+    """Partially build a CustomPromptSession with just enough state to call
+    `_active_ui_state()`. Avoids the full `__init__` which touches filesystem
+    history and clipboard."""
+    from kimi_cli.ui.shell.prompt import CustomPromptSession
+
+    session = object.__new__(CustomPromptSession)
+    session._running_prompt_delegate = None  # type: ignore[attr-defined]
+    session._modal_delegates = []  # type: ignore[attr-defined]
+    if delegate is not None:
+        session._modal_delegates.append(delegate)  # type: ignore[attr-defined]
+    return session
+
+
+def test_active_ui_state_is_modal_text_input_for_text_accepting_delegate() -> None:
+    """When the active modal delegate accepts text input, the session reports
+    MODAL_TEXT_INPUT. The escape key binding's eager filter relies on this to
+    drop out of eager mode so that default emacs Alt+X sequences (notably
+    Alt+Backspace → backward-kill-word) reach the buffer (#1744).
+    """
+    from kimi_cli.ui.shell.prompt import PromptUIState
+
+    class _TextInputDelegate:
+        modal_priority = 10
+
+        @staticmethod
+        def running_prompt_hides_input_buffer() -> bool:
+            return False
+
+        @staticmethod
+        def running_prompt_allows_text_input() -> bool:
+            return True
+
+    session = _make_prompt_session_stub(_TextInputDelegate())
+    assert session._active_ui_state() == PromptUIState.MODAL_TEXT_INPUT  # type: ignore[attr-defined]
+
+
+def test_active_ui_state_is_normal_for_non_text_input_delegate() -> None:
+    """A modal that does not accept text input (e.g. question panel in
+    multi-choice mode) should leave the session in NORMAL_INPUT so plain
+    Escape closes it eagerly."""
+    from kimi_cli.ui.shell.prompt import PromptUIState
+
+    class _ChoiceOnlyDelegate:
+        modal_priority = 10
+
+        @staticmethod
+        def running_prompt_hides_input_buffer() -> bool:
+            return False
+
+        @staticmethod
+        def running_prompt_allows_text_input() -> bool:
+            return False
+
+    session = _make_prompt_session_stub(_ChoiceOnlyDelegate())
+    assert session._active_ui_state() == PromptUIState.NORMAL_INPUT  # type: ignore[attr-defined]
+
+
+def test_active_ui_state_is_modal_hidden_for_buffer_hiding_delegate() -> None:
+    """A modal that hides the input buffer (approval panel, btw modal) should
+    report MODAL_HIDDEN_INPUT; the eager escape filter stays eager in that
+    state."""
+    from kimi_cli.ui.shell.prompt import PromptUIState
+
+    class _HiddenBufferDelegate:
+        modal_priority = 10
+
+        @staticmethod
+        def running_prompt_hides_input_buffer() -> bool:
+            return True
+
+        @staticmethod
+        def running_prompt_allows_text_input() -> bool:
+            return False
+
+    session = _make_prompt_session_stub(_HiddenBufferDelegate())
+    assert session._active_ui_state() == PromptUIState.MODAL_HIDDEN_INPUT  # type: ignore[attr-defined]