Add --help, --version, and TTY detection to CLI

src/dippy/dippy.py

@@ -271,6 +271,39 @@ def main():
     """Main entry point for the hook."""
     global MODE
 
+    # Early exit flags — checked before reading stdin
+    if "--help" in sys.argv or "-h" in sys.argv:
+        from dippy import __version__
+
+        print(f"Dippy v{__version__} — approval autopilot for AI coding assistants")
+        print()
+        print("Usage: dippy [--claude|--gemini|--cursor]")
+        print()
+        print("Reads JSON hook payload from stdin. Outputs a JSON decision.")
+        print()
+        print("Modes:")
+        print("  --claude   Force Claude Code mode")
+        print("  --gemini   Force Gemini CLI mode")
+        print("  --cursor   Force Cursor mode")
+        print("  (auto-detected from input if not specified)")
+        print()
+        print("Flags:")
+        print("  --help, -h       Show this help")
+        print("  --version, -V    Show version")
+        raise SystemExit(0)
+
+    if "--version" in sys.argv or "-V" in sys.argv:
+        from dippy import __version__
+
+        print(f"dippy {__version__}")
+        raise SystemExit(0)
+
+    # If stdin is a TTY, no input is being piped — show help instead of hanging
+    if sys.stdin.isatty():
+        print("dippy: no input (expected JSON on stdin)")
+        print("Run 'dippy --help' for usage.")
+        raise SystemExit(0)
+
     setup_logging()
 
     try:

tests/test_dippy.py

@@ -3966,6 +3966,69 @@ def test_command(check, cmd, expected_safe):
         assert needs_confirmation(result), f"Expected confirmation for: {cmd}"
 
 
+class TestCLI:
+    """Test CLI flags (--help, --version) and TTY detection."""
+
+    def test_help_flag(self, capsys):
+        import sys
+        from unittest.mock import patch
+
+        with patch.object(sys, "argv", ["dippy", "--help"]):
+            from dippy.dippy import main
+
+            with pytest.raises(SystemExit) as exc_info:
+                main()
+            assert exc_info.value.code == 0
+        captured = capsys.readouterr()
+        assert "Usage:" in captured.out
+        assert "--claude" in captured.out
+
+    def test_help_flag_short(self, capsys):
+        import sys
+        from unittest.mock import patch
+
+        with patch.object(sys, "argv", ["dippy", "-h"]):
+            from dippy.dippy import main
+
+            with pytest.raises(SystemExit) as exc_info:
+                main()
+            assert exc_info.value.code == 0
+        captured = capsys.readouterr()
+        assert "Usage:" in captured.out
+
+    def test_version_flag(self, capsys):
+        import sys
+        from unittest.mock import patch
+
+        with patch.object(sys, "argv", ["dippy", "--version"]):
+            from dippy.dippy import main
+
+            with pytest.raises(SystemExit) as exc_info:
+                main()
+            assert exc_info.value.code == 0
+        captured = capsys.readouterr()
+        from dippy import __version__
+
+        assert __version__ in captured.out
+
+    def test_tty_shows_help(self, capsys):
+        """When stdin is a TTY (no piped input), show help instead of hanging."""
+        import sys
+        from unittest.mock import patch
+
+        with patch.object(sys, "argv", ["dippy"]), patch.object(
+            sys.stdin, "isatty", return_value=True
+        ):
+            from dippy.dippy import main
+
+            with pytest.raises(SystemExit) as exc_info:
+                main()
+            assert exc_info.value.code == 0
+        captured = capsys.readouterr()
+        assert "no input" in captured.out
+        assert "--help" in captured.out
+
+
 class TestPostToolUse:
     """Test PostToolUse hook handling."""