diff --git a/openapi_type/tests/fail/tuple_struct.rs b/openapi_type/tests/fail/tuple_struct.rs
new file mode 100644
index 0000000..146a236
--- /dev/null
+++ b/openapi_type/tests/fail/tuple_struct.rs
@@ -0,0 +1,6 @@
+use openapi_type::OpenapiType;
+
+#[derive(OpenapiType)]
+struct Foo(i64, i64);
+
+fn main() {}
diff --git a/openapi_type/tests/fail/tuple_struct.stderr b/openapi_type/tests/fail/tuple_struct.stderr
new file mode 100644
index 0000000..b5ceb01
--- /dev/null
+++ b/openapi_type/tests/fail/tuple_struct.stderr
@@ -0,0 +1,5 @@
+error: #[derive(OpenapiType)] does not support tuple structs
+ --> $DIR/tuple_struct.rs:4:11
+  |
+4 | struct Foo(i64, i64);
+  |           ^^^^^^^^^^
diff --git a/openapi_type/tests/fail/tuple_variant.rs b/openapi_type/tests/fail/tuple_variant.rs
new file mode 100644
index 0000000..92aa8d7
--- /dev/null
+++ b/openapi_type/tests/fail/tuple_variant.rs
@@ -0,0 +1,8 @@
+use openapi_type::OpenapiType;
+
+#[derive(OpenapiType)]
+enum Foo {
+	Pair(i64, i64)
+}
+
+fn main() {}
diff --git a/openapi_type/tests/fail/tuple_variant.stderr b/openapi_type/tests/fail/tuple_variant.stderr
new file mode 100644
index 0000000..05573cb
--- /dev/null
+++ b/openapi_type/tests/fail/tuple_variant.stderr
@@ -0,0 +1,5 @@
+error: #[derive(OpenapiType)] does not support tuple variants
+ --> $DIR/tuple_variant.rs:5:6
+  |
+5 |     Pair(i64, i64)
+  |         ^^^^^^^^^^
diff --git a/openapi_type/tests/fail/union.rs b/openapi_type/tests/fail/union.rs
new file mode 100644
index 0000000..d011109
--- /dev/null
+++ b/openapi_type/tests/fail/union.rs
@@ -0,0 +1,9 @@
+use openapi_type::OpenapiType;
+
+#[derive(OpenapiType)]
+union Foo {
+	signed: i64,
+	unsigned: u64
+}
+
+fn main() {}
diff --git a/openapi_type/tests/fail/union.stderr b/openapi_type/tests/fail/union.stderr
new file mode 100644
index 0000000..f0feb48
--- /dev/null
+++ b/openapi_type/tests/fail/union.stderr
@@ -0,0 +1,5 @@
+error: #[derive(OpenapiType)] cannot be used on unions
+ --> $DIR/union.rs:4:1
+  |
+4 | union Foo {
+  | ^^^^^
diff --git a/openapi_type/tests/fail/unknown_attribute.rs b/openapi_type/tests/fail/unknown_attribute.rs
new file mode 100644
index 0000000..70a4785
--- /dev/null
+++ b/openapi_type/tests/fail/unknown_attribute.rs
@@ -0,0 +1,7 @@
+use openapi_type::OpenapiType;
+
+#[derive(OpenapiType)]
+#[openapi(pizza)]
+struct Foo;
+
+fn main() {}
diff --git a/openapi_type/tests/fail/unknown_attribute.stderr b/openapi_type/tests/fail/unknown_attribute.stderr
new file mode 100644
index 0000000..2558768
--- /dev/null
+++ b/openapi_type/tests/fail/unknown_attribute.stderr
@@ -0,0 +1,5 @@
+error: Unexpected token
+ --> $DIR/unknown_attribute.rs:4:11
+  |
+4 | #[openapi(pizza)]
+  |           ^^^^^
diff --git a/openapi_type_derive/src/parser.rs b/openapi_type_derive/src/parser.rs
index 5e57736..350fee2 100644
--- a/openapi_type_derive/src/parser.rs
+++ b/openapi_type_derive/src/parser.rs
@@ -35,7 +35,12 @@ fn parse_named_fields(named_fields: &FieldsNamed) -> syn::Result<ParseData> {
 pub(super) fn parse_struct(strukt: &DataStruct) -> syn::Result<ParseData> {
 	match &strukt.fields {
 		Fields::Named(named_fields) => parse_named_fields(named_fields),
-		Fields::Unnamed(_) => unimplemented!(),
+		Fields::Unnamed(unnamed_fields) => {
+			return Err(syn::Error::new(
+				unnamed_fields.span(),
+				"#[derive(OpenapiType)] does not support tuple structs"
+			))
+		},
 		Fields::Unit => Ok(ParseData::Unit)
 	}
 }
@@ -50,7 +55,12 @@ pub(super) fn parse_enum(inum: &DataEnum, attrs: &ContainerAttributes) -> syn::R
 			Fields::Named(named_fields) => {
 				types.push((name, parse_named_fields(named_fields)?));
 			},
-			Fields::Unnamed(_unnamed_fields) => unimplemented!(),
+			Fields::Unnamed(unnamed_fields) => {
+				return Err(syn::Error::new(
+					unnamed_fields.span(),
+					"#[derive(OpenapiType)] does not support tuple variants"
+				))
+			},
 			Fields::Unit => strings.push(name)
 		}
 	}