Don't use Bash bind -x for llm chat on Windows

llm/cli.py

@@ -1267,13 +1267,13 @@ def chat(
     """
     Hold an ongoing chat with a model.
     """
-    # Left and right arrow keys to move cursor:
-    if sys.platform != "win32":
+    # Left and right arrow keys to move cursor.
+    # pyreadline3 on Windows does not implement Bash `bind -x`.
+    try:
         readline.parse_and_bind("\\e[D: backward-char")
         readline.parse_and_bind("\\e[C: forward-char")
-    else:
-        readline.parse_and_bind("bind -x '\\e[D: backward-char'")
-        readline.parse_and_bind("bind -x '\\e[C: forward-char'")
+    except Exception:
+        pass
     log_path = pathlib.Path(database) if database else logs_db_path()
     (log_path.parent).mkdir(parents=True, exist_ok=True)
     db = sqlite_utils.Database(log_path)

tests/test_chat.py

@@ -355,3 +355,35 @@ def test_chat_fragments(tmpdir):
     ).output
     assert '"prompt": "one' in output
     assert '"prompt": "two"' in output
+
+
+def test_chat_readline_does_not_use_bash_bind_x(mock_model, logs_db, monkeypatch):
+    calls = []
+    monkeypatch.setattr(
+        llm.cli.readline, "parse_and_bind", lambda spec: calls.append(spec)
+    )
+    mock_model.enqueue(["ok"])
+    result = CliRunner().invoke(
+        llm.cli.cli,
+        ["chat", "-m", "mock"],
+        input="Hi\nquit\n",
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0
+    assert calls == ["\\e[D: backward-char", "\\e[C: forward-char"]
+
+
+def test_chat_survives_readline_bind_errors(mock_model, logs_db, monkeypatch):
+    def boom(_spec):
+        raise ValueError("pyreadline3 does not support this bind")
+
+    monkeypatch.setattr(llm.cli.readline, "parse_and_bind", boom)
+    mock_model.enqueue(["ok"])
+    result = CliRunner().invoke(
+        llm.cli.cli,
+        ["chat", "-m", "mock"],
+        input="Hi\nquit\n",
+        catch_exceptions=False,
+    )
+    assert result.exit_code == 0
+    assert "ok" in result.output