diff --git a/src/embit/descriptor/miniscript.py b/src/embit/descriptor/miniscript.py
index 990e3e5..39c0cb2 100644
--- a/src/embit/descriptor/miniscript.py
+++ b/src/embit/descriptor/miniscript.py
@@ -870,6 +870,11 @@ def inner_compile(self):
 
     def __len__(self):
         return len(self.arg) + 1
+    
+    def verify(self):
+        super().verify()
+        if self.arg.type != "V":
+            raise MiniscriptError("t: X must be of type V")
 
     @property
     def properties(self):
diff --git a/tests/tests/test_descriptor.py b/tests/tests/test_descriptor.py
index de3e4a6..b58d99e 100644
--- a/tests/tests/test_descriptor.py
+++ b/tests/tests/test_descriptor.py
@@ -199,6 +199,14 @@ def test_miniscript_compat(self):
         for desc in generalistic_descs:
             Descriptor.from_string(desc)
 
+    def test_invalid_miniscript(self):
+        """Ensure an error is raised when parsing invalid miniscript"""
+        invalid_descs = [
+            "wsh(ttvtvtvtvtvtvtv:after(230775))",
+        ]
+        for desc in invalid_descs:
+            self.assertRaises(MiniscriptError, Descriptor.from_string, desc)
+    
     def test_len(self):
         """Checks that len(miniscript) returns correct length"""
         for op in OPERATORS: