diff --git a/TCT/TCT_neighborhood_finder.py b/TCT/TCT_neighborhood_finder.py
index 4c8018a..068a56d 100644
--- a/TCT/TCT_neighborhood_finder.py
+++ b/TCT/TCT_neighborhood_finder.py
@@ -1,7 +1,8 @@
 from collections import Counter
 
-from .TCT import sele_predicates_API, format_query_json, parse_KG, rank_by_primary_infores
+from .TCT import sele_predicates_API, parse_KG, rank_by_primary_infores
 from .TCT_pathfinder import generate_score_results, build_query_graph
+from .translator_query import format_query_json
 
 def parse_results_for_neighborhood_finder(start_node_id:str, results:dict,
         start_node_categories=None, end_node_categories=None,
diff --git a/TCT/TCT_pathfinder.py b/TCT/TCT_pathfinder.py
index b4eaa28..f3c9109 100644
--- a/TCT/TCT_pathfinder.py
+++ b/TCT/TCT_pathfinder.py
@@ -5,62 +5,7 @@
 
 from . import node_normalizer
 from . import translator_query
-from .TCT import sele_predicates_API, parse_KG, rank_by_primary_infores, merge_ranking_by_number_of_infores
-
-def format_query_json_for_pathfinder(subject_ids, 
-                                     object_ids=None,
-        subject_categories=None,
-        object_categories=None,
-        predicates=None):
-    '''
-    Example input:
-    subject_ids = ["NCBIGene:3845"]
-    object_ids = []
-    subject_categories = ["biolink:Gene"]
-    object_categories = ["biolink:Gene"]
-    predicates = ["biolink:positively_correlated_with", "biolink:physically_interacts_with"]
-    '''
-    query_json_temp = {
-        "message": {
-            "query_graph": {
-
-                "edges": {
-                    "e00": {
-                        "subject": "n00",
-                        "object": "n01",
-                        "predicates": predicates
-                        }
-                    },
-                "nodes": {
-                    "n00": {
-                        "ids":subject_ids, # required
-                        #"categories":[] # optional, if not provided, it will be empty
-                        },
-                    "n01": {
-                        #"ids":[],
-                        "categories":[] # required
-                        }
-                    }
-                }
-            }
-        }
-
-    if len(subject_ids) > 0:
-        query_json_temp["message"]["query_graph"]["nodes"]["n00"]["ids"] = subject_ids
-
-    if object_ids is not None and len(object_ids) > 0:
-        query_json_temp["message"]["query_graph"]["nodes"]["n01"]["ids"] = object_ids
-
-    if subject_categories is not None and len(subject_categories) > 0:
-        query_json_temp["message"]["query_graph"]["nodes"]["n00"]["categories"] = subject_categories
-
-    if object_categories is not None and len(object_categories) > 0:
-        query_json_temp["message"]["query_graph"]["nodes"]["n01"]["categories"] = object_categories
-
-    if predicates is not None and len(predicates) > 0:
-        query_json_temp["message"]["query_graph"]["edges"]["e00"]["predicates"] = predicates
-
-    return query_json_temp
+from .TCT import sele_predicates_API
 
 
 def build_query_graph(start_node_id, end_node_id, start_node_categories=None, end_node_categories=None):
@@ -289,14 +234,14 @@ def pathfinder(input_node1_id:str, input_node2_id:str,
     sele_predicates2, sele_APIs2, API_URLs2 = sele_predicates_API(intermediate_categories,
                                                                   input_node2_category,
                                                                   metaKG, APInames)
-    query_json1 = format_query_json_for_pathfinder(input_node1_list,  # a list of identifiers for input node1
+    query_json1 = translator_query.format_query_json(input_node1_list,  # a list of identifiers for input node1
                                     [],  # id list for the intermediate node, it can be empty list if only want to query node1
                                     input_node1_category,  # a list of categories of input node1
                                     intermediate_categories,  # a list of categories of the intermediate node
                                     sele_predicates1) # a list of predicates
 
     # for the second hop, we want the predicates to be...
-    query_json2 = format_query_json_for_pathfinder([], 
+    query_json2 = translator_query.format_query_json([], 
                                     input_node2_list,  
                                     intermediate_categories,  # a list of categories of input node2
                                     input_node2_category,  # a list of categories of the intermediate node
diff --git a/TCT/translator_query.py b/TCT/translator_query.py
index 870b153..9baaac8 100644
--- a/TCT/translator_query.py
+++ b/TCT/translator_query.py
@@ -43,6 +43,90 @@ def get_translator_API_predicates() -> tuple[dict, pandas.DataFrame, dict]:
 
     return APInames, metaKG, API_predicates
 
+
+def build_attribute_constraint(attribute_id, operator, value, name=None, is_not=False):
+    """
+    This creates an attribute constraint for a TRAPI query dict.
+    """
+    if name is None:
+        name = ''
+    output = {
+            'id': attribute_id,
+            'operator': operator,
+            'value': value,
+            'name': name
+            }
+    if is_not:
+        output['not'] = True
+    return output
+
+
+def format_query_json(subject_ids:list[str],
+        object_ids:list[str]|None = None,
+        subject_categories:list[str]|None = None,
+        object_categories:list[str]|None = None,
+        predicates:list[str]|None = None,
+        attribute_constraints:list[dict]|None = None,
+        ) -> dict:
+    '''
+    Formats a query dict, with optional constraints.
+
+    Example input:
+    subject_ids = ["NCBIGene:3845"]
+    object_ids = []
+    subject_categories = ["biolink:Gene"]
+    object_categories = ["biolink:Gene"]
+    predicates = ["biolink:positively_correlated_with", "biolink:physically_interacts_with"]
+    attribute_constraints = [build_attribute_constraint('biolink:has_total', '>', 2)]
+    '''
+    #edited Dec 5, 2023
+    query_json_temp = {
+        "message": {
+            "query_graph": {
+
+                "edges": {
+                    "e00": {
+                    #"e1": {
+                        "subject": "n01",
+                        "object": "n00",
+                        "predicates": predicates
+                        }
+                    },
+                "nodes": {
+                    "n00": {
+                        "ids":subject_ids, # required
+                        #"categories":[] # optional, if not provided, it will be empty
+                        },
+                    "n01": {
+                        #"ids":[],
+                        "categories":[] # required
+                        }}
+                }
+            }
+        }
+
+    if attribute_constraints is not None and len(attribute_constraints) > 0:
+        query_json_temp['message']['query_graph']['edges']['attribute_constraints'] = attribute_constraints
+
+    if subject_ids is not None and len(subject_ids) > 0:
+        query_json_temp["message"]["query_graph"]["nodes"]["n00"]["ids"] = subject_ids
+
+    if object_ids is not None and len(object_ids) > 0:
+        query_json_temp["message"]["query_graph"]["nodes"]["n01"]["ids"] = object_ids
+
+    if subject_categories is not None and len(subject_categories) > 0:
+        query_json_temp["message"]["query_graph"]["nodes"]["n01"]["categories"] = subject_categories
+
+    if object_categories is not None and len(object_categories) > 0:
+        query_json_temp["message"]["query_graph"]["nodes"]["n01"]["categories"] = object_categories
+
+    if predicates is not None and len(predicates) > 0:
+        query_json_temp["message"]["query_graph"]["edges"]["e00"]["predicates"] = predicates
+
+    return query_json_temp
+
+
+
 def optimize_query_json(query_json, API_name_cur, API_predicates):
     '''
     Optimize the query JSON by removing predicates that are not supported by the selected APIs.