diff --git a/src/modeci_mdf/execution_engine.py b/src/modeci_mdf/execution_engine.py
index e2abde9c..2f55cdd8 100644
--- a/src/modeci_mdf/execution_engine.py
+++ b/src/modeci_mdf/execution_engine.py
@@ -12,6 +12,7 @@
 
 """
 import ast
+import builtins
 import copy
 import functools
 import inspect
@@ -53,7 +54,7 @@
 
 FORMAT_DEFAULT = FORMAT_NUMPY
 
-KNOWN_PARAMETERS = ["constant"]
+KNOWN_PARAMETERS = ["constant", "math", "numpy"] + dir(builtins)
 
 
 time_scale_str_regex = r"(TimeScale)?\.(.*)"
@@ -778,8 +779,20 @@ def __init__(self, node: Node, verbose: Optional[bool] = False):
 
                     # If we are dealing with a list of symbols, each must treated separately
                     all_req_vars.extend(
-                        get_required_variables_from_expression(arg_expr)
+                        [
+                            v
+                            for v in get_required_variables_from_expression(arg_expr)
+                            if v not in f.args
+                        ]
                     )
+            if f.value is not None:
+                all_req_vars.extend(
+                    [
+                        v
+                        for v in get_required_variables_from_expression(f.value)
+                        if f.args is None or v not in f.args
+                    ]
+                )
 
             all_present = [v in all_known_vars for v in all_req_vars]
             func_missing_vars[f.id] = {
@@ -839,14 +852,26 @@ def __init__(self, node: Node, verbose: Optional[bool] = False):
             all_req_vars = []
 
             if p.value is not None and type(p.value) == str:
-                all_req_vars.extend(get_required_variables_from_expression(p.value))
+                all_req_vars.extend(
+                    [
+                        v
+                        for v in get_required_variables_from_expression(p.value)
+                        if p.args is None or v not in p.args
+                    ]
+                )
 
             if p.args is not None:
                 for arg in p.args:
                     arg_expr = p.args[arg]
                     if isinstance(arg_expr, str):
                         all_req_vars.extend(
-                            get_required_variables_from_expression(arg_expr)
+                            [
+                                v
+                                for v in get_required_variables_from_expression(
+                                    arg_expr
+                                )
+                                if v not in p.args
+                            ]
                         )
 
             all_known_vars_plus_this = all_known_vars + [p.id]
diff --git a/tests/test_execution.py b/tests/test_execution.py
index 22b7e187..6b30328c 100644
--- a/tests/test_execution.py
+++ b/tests/test_execution.py
@@ -22,11 +22,9 @@
         {"slope": 2, "intercept": 4, "variable0": "input"},
         {"slope": 2, "intercept": 4, "variable0": "input"},
         {"slope": "2 * input", "intercept": 4, "variable0": "input"},
-        # expressions as arg values referencing other args is not currently supported
-        pytest.param(
-            {"slope": 2, "intercept": "2 * slope", "variable0": "input"},
-            marks=pytest.mark.xfail,
-        ),
+        {"slope": 2, "intercept": "2 * slope", "variable0": "input"},
+        {"slope": "math.sqrt(4)", "intercept": 4, "variable0": 1},
+        {"slope": "numpy.sqrt(4)", "intercept": 4, "variable0": 1},
     ],
 )
 def test_single_function_variations(create_model, args, function, value, result):
@@ -85,3 +83,42 @@ def test_condition_variations(create_model, node_specific, termination, result):
     eg.evaluate(initializer={"A_input": 0})
 
     assert eg.enodes["A"].evaluable_outputs["A_output"].curr_value == result
+
+
+def test_dependency_in_function_value(create_model):
+    m = create_model(
+        [
+            mdf.Node(
+                id="N",
+                input_ports=[mdf.InputPort(id="input")],
+                functions=[
+                    mdf.Function(id="f", value="g"),
+                    mdf.Function(id="g", value="1"),
+                ],
+                output_ports=[mdf.OutputPort(id="output", value="f")],
+            )
+        ]
+    )
+
+    eg = EvaluableGraph(m.graphs[0])
+    eg.evaluate(initializer={"input": 1})
+
+
+# NOTE: this is enabled by "don't include known args in required variable"
+# but could not be tested until dependency checking for value
+def test_available_arg_in_function_value(create_model):
+    m = create_model(
+        [
+            mdf.Node(
+                id="N",
+                input_ports=[mdf.InputPort(id="input")],
+                functions=[
+                    mdf.Function(id="f", args={"g": 1}, value="g"),
+                ],
+                output_ports=[mdf.OutputPort(id="output", value="f")],
+            )
+        ]
+    )
+
+    eg = EvaluableGraph(m.graphs[0])
+    eg.evaluate(initializer={"input": 1})