fix(cli): preserve Ctrl-J newline on macOS

cli.py

@@ -1913,7 +1913,7 @@ def _strip_leaked_bracketed_paste_wrappers(text: str) -> str:
 def _preserve_ctrl_enter_newline() -> bool:
     """Detect environments where Ctrl+Enter must produce a newline, not submit.
 
-    Native Windows, WSL, SSH sessions, and Windows Terminal all send Ctrl+Enter
+    Native macOS, Windows, WSL, SSH sessions, and Windows Terminal all send Ctrl+Enter
     as bare LF (c-j). On those terminals c-j must NOT be bound to submit;
     binding it to submit makes Ctrl+Enter (intended as 'newline like Alt+Enter')
     submit instead. Local POSIX TTYs that deliver Enter as LF (docker exec,
@@ -1922,7 +1922,7 @@ def _preserve_ctrl_enter_newline() -> bool:
 
     See issue #22379.
     """
-    if sys.platform == "win32":
+    if sys.platform in {"darwin", "win32"}:
         return True
     if any(os.environ.get(v) for v in ("SSH_CONNECTION", "SSH_CLIENT", "SSH_TTY")):
         return True
@@ -1948,7 +1948,7 @@ def _bind_prompt_submit_keys(kb, handler) -> None:
     some thin PTYs (docker exec, certain SSH flavors) deliver Enter as LF
     instead of CR — without this, Enter appears dead on those terminals.
 
-    Exception: on Windows, WSL, SSH sessions, and Windows Terminal,
+    Exception: on macOS, Windows, WSL, SSH sessions, and Windows Terminal,
     c-j is the wire encoding of Ctrl+Enter (a distinct keystroke from
     plain Enter / c-m). We leave c-j unbound there so the c-j newline
     handler registered separately can fire — giving the user an
@@ -5187,7 +5187,7 @@ def show_help(self):
                 )
 
         _cprint(f"\n  {_DIM}Tip: Just type your message to chat with Hermes!{_RST}")
-        _cprint(f"  {_DIM}Multi-line: Alt+Enter for a new line{_RST}")
+        _cprint(f"  {_DIM}Multi-line: Ctrl+J or Alt+Enter for a new line{_RST}")
         _cprint(f"  {_DIM}Draft editor: Ctrl+G (Alt+G in VSCode/Cursor){_RST}")
         if _is_termux_environment():
             _cprint(f"  {_DIM}Attach image: /image {_termux_example_image_path()} or start your prompt with a local image path{_RST}\n")
@@ -11421,7 +11421,7 @@ def handle_alt_enter(event):
 
             Works on mac/Linux/WSL. On Windows Terminal this keystroke is
             intercepted at the terminal layer (toggles fullscreen) and never
-            reaches here — Windows users get newline via Ctrl+Enter instead
+            reaches here — Windows and macOS users get newline via Ctrl+J/Ctrl+Enter instead
             (bound below as c-j, since WT delivers Ctrl+Enter as LF).
             """
             event.current_buffer.insert_text('\n')

tests/cli/test_cli_init.py

@@ -168,7 +168,7 @@ def test_lf_enter_binds_to_submit_handler_posix(self):
 
         On a bare local POSIX TTY (no SSH/WSL/WT) we keep c-j → submit so
         Enter works on thin PTYs (docker exec, certain ssh configurations).
-        On Windows, WSL, SSH sessions, and Windows Terminal we leave c-j
+        On macOS, Windows, WSL, SSH sessions, and Windows Terminal we leave c-j
         unbound here so it can be used as the Ctrl+Enter newline keystroke
         without conflicting with submit. See issue #22379.
         """
@@ -203,6 +203,16 @@ def submit_handler(event):
             assert bindings[("c-m",)] is submit_handler
             assert ("c-j",) not in bindings
 
+        # macOS: only enter submits; c-j is free for the newline binding
+        # added separately in the prompt setup.
+        with _patch.object(_sys, "platform", "darwin"), \
+             _patch.dict(_os.environ, {}, clear=True):
+            kb = KeyBindings()
+            _bind_prompt_submit_keys(kb, submit_handler)
+            bindings = {tuple(key.value for key in binding.keys): binding.handler for binding in kb.bindings}
+            assert bindings[("c-m",)] is submit_handler
+            assert ("c-j",) not in bindings
+
         # Windows: only enter submits; c-j is free for the newline binding
         # added separately in the prompt setup.
         with _patch.object(_sys, "platform", "win32"):

tests/cli/test_ctrl_enter_newline.py

@@ -22,6 +22,13 @@ def test_native_windows_preserves_newline():
         assert cli_mod._preserve_ctrl_enter_newline() is True
 
 
+def test_native_macos_preserves_newline():
+    import cli as cli_mod
+    with patch.object(sys, "platform", "darwin"):
+        with patch.dict(os.environ, {}, clear=True):
+            assert cli_mod._preserve_ctrl_enter_newline() is True
+
+
 def test_ssh_session_preserves_newline_on_linux():
     import cli as cli_mod
     with patch.object(sys, "platform", "linux"):