diff --git a/src/cranberry/fields.py b/src/cranberry/fields.py
index fd0de52..be72c3e 100644
--- a/src/cranberry/fields.py
+++ b/src/cranberry/fields.py
@@ -93,8 +93,8 @@ def metavar(self) -> str:
 # Public factory functions
 # ---------------------------------------------------------------------------
 def option(
-    short: str,
-    long: str,
+    short: str | None,
+    long: str | None,
     *,
     help: str = "",
     default: Any = None,
@@ -116,8 +116,8 @@ def option(
 
 
 def flag(
-    short: str,
-    long: str,
+    short: str | None,
+    long: str | None,
     *,
     help: str = "",
     default: bool = False,
@@ -159,8 +159,8 @@ def arg(
 
 
 def file(
-    short: str,
-    long: str,
+    short: str | None,
+    long: str | None,
     *,
     help: str = "",
     default: Any = None,
@@ -183,8 +183,8 @@ def file(
 
 
 def dir(
-    short: str,
-    long: str,
+    short: str | None,
+    long: str | None,
     *,
     help: str = "",
     default: Any = None,
diff --git a/tests/test_fields.py b/tests/test_fields.py
index c5c7888..2e75e01 100644
--- a/tests/test_fields.py
+++ b/tests/test_fields.py
@@ -65,6 +65,16 @@ def test_validate_stored(self):
         spec = cb.option("-o", "--opt", validate=v)
         assert spec.validate is v
 
+    def test_none_short(self):
+        spec = cb.option(None, "--opt")
+        assert spec.short is None
+        assert spec.long is not None
+
+    def test_none_long(self):
+        spec = cb.option("--opt", None)
+        assert spec.short is not None
+        assert spec.long is None
+
 
 # ---------------------------------------------------------------------------
 # flag()
@@ -82,6 +92,22 @@ def test_default_false(self):
     def test_default_true(self):
         assert cb.flag("-f", "--flag", default=True).default is True
 
+    def test_stackable_false(self):
+        assert cb.flag("-f", "--flag").stackable is False
+
+    def test_stackable_true(self):
+        assert cb.flag("-f", "--flag", stackable=True).stackable is True
+
+    def test_none_short(self):
+        spec = cb.flag(None, "--flag")
+        assert spec.short is None
+        assert spec.long is not None
+
+    def test_none_long(self):
+        spec = cb.flag("--flag", None)
+        assert spec.short is not None
+        assert spec.long is None
+
 
 # ---------------------------------------------------------------------------
 # arg()
@@ -105,6 +131,10 @@ def test_enforce_count_default_false(self):
     def test_enforce_count_true(self):
         assert cb.arg(enforce_count=True).enforce_count is True
 
+    def test_type(self):
+        assert cb.arg(type=int).type is int
+        assert cb.arg(type=str).type is str
+
 
 # ---------------------------------------------------------------------------
 # file()