diff --git a/heat/engine/api.py b/heat/engine/api.py
index 3d12d50cd5..c19b4f9f53 100644
--- a/heat/engine/api.py
+++ b/heat/engine/api.py
@@ -524,6 +524,12 @@ def format_validate_parameter(param):
     if param.user_value:
         res[rpc_api.PARAM_VALUE] = param.user_value
 
+    _build_parameter_constraints(res, param)
+
+    return res
+
+
+def _build_parameter_constraints(res, param):
     constraint_description = []
 
     # build constraints
@@ -565,8 +571,6 @@ def format_validate_parameter(param):
         res[rpc_api.PARAM_CONSTRAINT_DESCRIPTION] = " ".join(
             constraint_description)
 
-    return res
-
 
 def format_software_config(sc, detail=True, include_project=False):
     if sc is None: