diff --git a/oks_cli/main.py b/oks_cli/main.py
index 6cd72d7..c67f295 100755
--- a/oks_cli/main.py
+++ b/oks_cli/main.py
@@ -82,7 +82,7 @@ def version():
     print(importlib.metadata.version(__package__))
 
 @cli.command("install-completion", help="Install shell completion scripts.")
-@click.option('--type', required=True, help="Shell, supported [bash,zsh]")
+@click.option('--type', help="Shell, supported [bash,zsh]")
 def install_completion(type):
     """Install shell completion scripts for the CLI."""
     install_completions(type)
diff --git a/oks_cli/utils.py b/oks_cli/utils.py
index a8fdebe..b7cb2f0 100644
--- a/oks_cli/utils.py
+++ b/oks_cli/utils.py
@@ -801,6 +801,17 @@ def find_shell_profile(home, shell_type):
 def install_completions(shell_type):
     """Install shell completion scripts for bash or zsh."""
     home = os.path.expanduser('~')
+
+    if shell_type is None:
+        try:
+            shell_pid = os.getppid()
+            result = subprocess.run(['ps', '-p', str(shell_pid), '-o', 'comm='], capture_output=True, text=True)
+            shell_name = result.stdout.strip()
+
+            shell_type = os.path.basename(shell_name).lstrip('-')
+        except subprocess.SubProcessError:
+            click.echo("Failed to determine shell type, please specify it by --type")
+
     completion_dir = os.path.join(home, ".oks_cli", "completions")
     os.makedirs(completion_dir, exist_ok=True)
 
diff --git a/tests/test_install_completion.py b/tests/test_install_completion.py
deleted file mode 100644
index 327e746..0000000
--- a/tests/test_install_completion.py
+++ /dev/null
@@ -1,24 +0,0 @@
-from click.testing import CliRunner
-from oks_cli.main import cli
-# from unittest.mock import patch, MagicMock
-
-def test_install_completion_command_type_required():
-    """ Test --type option is required """
-    runner = CliRunner()
-    result = runner.invoke(cli, ["install-completion"])
-    assert result.exit_code == 2
-    assert "Missing option '--type'" in result.output
-
-def test_install_completion_command_wrong_type():
-    """ Test --type supported values """
-    runner = CliRunner()
-    result = runner.invoke(cli, ["install-completion", "--type", "fake-shell"])
-    assert result.exit_code == 2
-    assert "Shell completions for fake-shell are not implemented" in result.output
-
-def test_install_completion_command():
-    """ Test working shell """
-    runner = CliRunner()
-    result = runner.invoke(cli, ["install-completion", "--type", "bash"])
-    assert result.exit_code == 0
-    assert "Autocompletion installed for bash" in result.output
\ No newline at end of file