fix(cli): truncate multi-line shell commands in HITL approval (#3314)

Closes #1095

---

The existing 120-char truncation in the approval prompt only collapsed
horizontally long commands. Multi-line commands where each line was
short (e.g. a `python3 -c` one-liner with embedded newlines) bypassed
the per-line threshold and rendered untruncated — pushing the
approve/reject options far down the terminal.

Adds a line-count threshold (`_SHELL_COMMAND_TRUNCATE_LINES = 5`)
alongside the existing character threshold and applies both inside the
same `press 'e' to expand` affordance, so the user experience is
unchanged for short commands and consistent (one ellipsis, one expand
hint) for any command that exceeds either dimension.

Co-authored-by: open-swe[bot] <open-swe@users.noreply.github.com>
Co-authored-by: Mason Daugherty <61371264+mdrxy@users.noreply.github.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>

libs/cli/deepagents_cli/widgets/approval.py

@@ -36,10 +36,52 @@ from deepagents_cli.widgets.tool_renderers import get_renderer
 
 # Max length for truncated shell command display
 _SHELL_COMMAND_TRUNCATE_LENGTH: int = 120
+# Max number of lines for truncated shell command display
+_SHELL_COMMAND_TRUNCATE_LINES: int = 5
 _WARNING_PREVIEW_LIMIT: int = 3
 _WARNING_TEXT_TRUNCATE_LENGTH: int = 220
 
 
+def _is_command_too_long(command: str) -> bool:
+    """Whether a shell command exceeds the display thresholds (char or line).
+
+    Args:
+        command: The shell command string to check.
+
+    Returns:
+        `True` if the command is longer than `_SHELL_COMMAND_TRUNCATE_LENGTH`
+        characters or has more than `_SHELL_COMMAND_TRUNCATE_LINES` lines.
+    """
+    if len(command) > _SHELL_COMMAND_TRUNCATE_LENGTH:
+        return True
+    return command.count("\n") + 1 > _SHELL_COMMAND_TRUNCATE_LINES
+
+
+def _truncate_command(command: str) -> str:
+    """Truncate a shell command for compact display.
+
+    Applies line truncation first (keeping at most `_SHELL_COMMAND_TRUNCATE_LINES`
+    lines), then character truncation, so multi-line commands collapse before
+    long single lines are cut. A single ellipsis is appended at the end.
+
+    Args:
+        command: The shell command string to truncate.
+
+    Returns:
+        The truncated command string, with a trailing ellipsis if any truncation
+        was applied; otherwise the original command unchanged.
+    """
+    ellipsis = get_glyphs().ellipsis
+    lines = command.split("\n")
+    truncated = len(lines) > _SHELL_COMMAND_TRUNCATE_LINES
+    if truncated:
+        command = "\n".join(lines[:_SHELL_COMMAND_TRUNCATE_LINES])
+    if len(command) > _SHELL_COMMAND_TRUNCATE_LENGTH:
+        command = command[:_SHELL_COMMAND_TRUNCATE_LENGTH]
+        truncated = True
+    return command + ellipsis if truncated else command
+
+
 class ApprovalMenu(Container):
     """Approval menu using standard Textual patterns.
 
@@ -143,7 +185,7 @@ class ApprovalMenu(Container):
         if req.get("name", "") not in SHELL_TOOL_NAMES:
             return False
         command = str(req.get("args", {}).get("command", ""))
-        return len(command) > _SHELL_COMMAND_TRUNCATE_LENGTH
+        return _is_command_too_long(command)
 
     def _get_command_display(self, *, expanded: bool) -> Content:
         """Get the command display content (truncated or full).
@@ -165,14 +207,13 @@ class ApprovalMenu(Container):
         command = strip_dangerous_unicode(command_raw)
         issues = detect_dangerous_unicode(command_raw)
 
-        if expanded or len(command) <= _SHELL_COMMAND_TRUNCATE_LENGTH:
+        too_long = _is_command_too_long(command)
+        if expanded or not too_long:
             command_display = command
         else:
-            command_display = (
-                command[:_SHELL_COMMAND_TRUNCATE_LENGTH] + get_glyphs().ellipsis
-            )
+            command_display = _truncate_command(command)
 
-        if not expanded and len(command) > _SHELL_COMMAND_TRUNCATE_LENGTH:
+        if not expanded and too_long:
             display = Content.from_markup(
                 "[bold]$cmd[/bold] [dim](press 'e' to expand)[/dim]",
                 cmd=command_display,

libs/cli/tests/unit_tests/test_approval.py

@@ -7,6 +7,7 @@ import pytest
 from deepagents_cli.config import get_glyphs
 from deepagents_cli.widgets.approval import (
     _SHELL_COMMAND_TRUNCATE_LENGTH,
+    _SHELL_COMMAND_TRUNCATE_LINES,
     ApprovalMenu,
 )
 
@@ -59,6 +60,22 @@ class TestCheckExpandableCommand:
         menu = ApprovalMenu({"name": "shell", "args": {}})
         assert menu._has_expandable_command is False
 
+    def test_multiline_command_over_line_threshold_is_expandable(self) -> None:
+        """Multi-line commands that exceed the line threshold are expandable.
+
+        Each line stays well under the character threshold, so this regresses
+        only if the line-count check is missing.
+        """
+        command = "\n".join(["echo line"] * (_SHELL_COMMAND_TRUNCATE_LINES + 1))
+        menu = ApprovalMenu({"name": "shell", "args": {"command": command}})
+        assert menu._has_expandable_command is True
+
+    def test_multiline_command_at_line_threshold_not_expandable(self) -> None:
+        """Commands at exactly the line threshold are not expandable."""
+        command = "\n".join(["echo line"] * _SHELL_COMMAND_TRUNCATE_LINES)
+        menu = ApprovalMenu({"name": "shell", "args": {"command": command}})
+        assert menu._has_expandable_command is False
+
 
 class TestGetCommandDisplay:
     """Tests for `ApprovalMenu._get_command_display`."""
@@ -137,6 +154,29 @@ class TestGetCommandDisplay:
         assert "U+202E" in display.plain
         assert "raw:" in display.plain
 
+    def test_multiline_command_truncated_to_max_lines(self) -> None:
+        """Multi-line commands collapse to the line cap with an expand hint."""
+        lines = [f"echo {i}" for i in range(_SHELL_COMMAND_TRUNCATE_LINES + 3)]
+        command = "\n".join(lines)
+        menu = ApprovalMenu({"name": "shell", "args": {"command": command}})
+        display = menu._get_command_display(expanded=False)
+        plain = display.plain
+        assert get_glyphs().ellipsis in plain
+        assert "press 'e' to expand" in plain
+        for kept in lines[:_SHELL_COMMAND_TRUNCATE_LINES]:
+            assert kept in plain
+        assert lines[_SHELL_COMMAND_TRUNCATE_LINES] not in plain
+
+    def test_multiline_command_shows_full_when_expanded(self) -> None:
+        """Expanded multi-line commands show every line."""
+        lines = [f"echo {i}" for i in range(_SHELL_COMMAND_TRUNCATE_LINES + 3)]
+        command = "\n".join(lines)
+        menu = ApprovalMenu({"name": "shell", "args": {"command": command}})
+        display = menu._get_command_display(expanded=True)
+        for line in lines:
+            assert line in display.plain
+        assert "press 'e' to expand" not in display.plain
+
 
 class TestToggleExpand:
     """Tests for `ApprovalMenu.action_toggle_expand`."""