diff --git a/royalnet/engineer/params.py b/royalnet/engineer/params.py
index c79fd411..4457750e 100644
--- a/royalnet/engineer/params.py
+++ b/royalnet/engineer/params.py
@@ -40,11 +40,11 @@ def parameter_to_field(param: inspect.Parameter, **kwargs) -> Tuple[type, pydant
 
 def signature_to_model(f: Callable, __config__: pydantic.BaseConfig = ModelConfig, **extra_params):
     """
-    Convert the signature of a function to a pydantic model.
+    Convert the signature of a async function to a pydantic model.
 
     Arguments starting with ``_`` are ignored.
 
-    :param f: The function to use the signature of.
+    :param f: The async function to use the signature of.
     :param __config__: The config the pydantic model should use.
     :param extra_params: Extra parameters to be added to the model.
     :return: The created pydantic model.
diff --git a/royalnet/engineer/router.py b/royalnet/engineer/router.py
index d0ec6d76..24391eda 100644
--- a/royalnet/engineer/router.py
+++ b/royalnet/engineer/router.py
@@ -18,7 +18,8 @@ class EngineerRouter:
 
         :param name: The name of the command (``start``, ``settings``, etc). If not specified, it will use the name
                      of the wrapped function.
-        :param f: The function that should be executed when the command is called. It must have a ``.model`` property.
+        :param f: The async function that should be executed when the command is called.
+                  It must have a ``.model`` property.
 
         .. seealso:: :meth:`.command`, :func:`.params.function_with_model`
         """
@@ -33,13 +34,13 @@ class EngineerRouter:
         .. code-block:: python
 
            @command()
-           def ping():
+           async def ping():
                print("Pong!")
 
         .. code-block:: python
 
            @command(name="ping")
-           def xyzzy():
+           async def xyzzy():
                print("Pong!")
 
         :param name: The name of the command (``start``, ``settings``, etc). If not specified, it will use the name
@@ -61,7 +62,18 @@ class EngineerRouter:
 
         return decorator
 
-    def call(self, __name: str, **kwargs):
+    async def call(self, __name: str, **kwargs) -> Any:
+        """
+        Call the command with the specified name using the passed kwargs.
+
+        :param __name: The name of the function.
+        :param kwargs: Kwargs to pass to the desired function:
+                       - Kwargs starting with ``__`` are never passed to the function.
+                       - Kwargs starting with ``_`` are passed as they are.
+                       - Other kwargs are validated by the function's :mod:`pydantic` model.
+        :return: The return value of the function.
+        :raises pydantic.ValidationError: If the kwargs do not pass the :mod:`pydantic` model validation.
+        """
         model_params = {}
         extra_params = {}
         for key, value in kwargs.items():
@@ -74,7 +86,7 @@ class EngineerRouter:
         # noinspection PyPep8Naming
         Model: Type[pydantic.BaseModel] = f.model
         model: pydantic.BaseModel = Model(**model_params)
-        return f(**model.dict(), **extra_params)
+        return await f(**model.dict(), **extra_params)
 
 
 __all__ = (
diff --git a/royalnet/engineer/tests/test_params.py b/royalnet/engineer/tests/test_params.py
index e636c672..6e0ddc5b 100644
--- a/royalnet/engineer/tests/test_params.py
+++ b/royalnet/engineer/tests/test_params.py
@@ -6,14 +6,14 @@ import royalnet.engineer as re
 
 
 @pytest.fixture
-def a_random_function():
+async def my_async_function():
     def f(*, big_f: str, _hidden: int) -> str:
         return big_f
     return f
 
 
-def test_parameter_to_field(a_random_function):
-    signature = inspect.signature(a_random_function)
+def test_parameter_to_field(my_async_function):
+    signature = inspect.signature(my_async_function)
     parameter = signature.parameters["big_f"]
     t, fieldinfo = re.parameter_to_field(parameter)
     assert isinstance(fieldinfo, pydantic.fields.FieldInfo)
@@ -21,8 +21,8 @@ def test_parameter_to_field(a_random_function):
     assert fieldinfo.title == parameter.name == "big_f"
 
 
-def test_signature_to_model(a_random_function):
-    Model = re.signature_to_model(a_random_function)
+def test_signature_to_model(my_async_function):
+    Model = re.signature_to_model(my_async_function)
     assert callable(Model)
 
     model = Model(big_f="banana")