diff --git a/azure_functions_worker/main.py b/azure_functions_worker/main.py
index 3edf28400..4e1f70a77 100644
--- a/azure_functions_worker/main.py
+++ b/azure_functions_worker/main.py
@@ -2,7 +2,6 @@
 # Licensed under the MIT License.
 """Main entrypoint."""
 
-
 import argparse
 
 
@@ -26,6 +25,18 @@ def parse_args():
                              'syslog, or a file path')
     parser.add_argument('--grpcMaxMessageLength', type=int,
                         dest='grpc_max_msg_len')
+    parser.add_argument('--functions-uri', dest='functions_uri', type=str,
+                        help='URI with IP Address and Port used to'
+                             ' connect to the Host via gRPC.')
+    parser.add_argument('--functions-request-id', dest='functions_request_id',
+                        type=str, help='Request ID used for gRPC communication '
+                                       'with the Host.')
+    parser.add_argument('--functions-worker-id',
+                        dest='functions_worker_id', type=str,
+                        help='Worker ID assigned to this language worker.')
+    parser.add_argument('--functions-grpc-max-message-length', type=int,
+                        dest='functions_grpc_max_msg_len',
+                        help='Max grpc message length for Functions')
     return parser.parse_args()
 
 
diff --git a/tests/unittests/test_main.py b/tests/unittests/test_main.py
new file mode 100644
index 000000000..2fe29c8c1
--- /dev/null
+++ b/tests/unittests/test_main.py
@@ -0,0 +1,79 @@
+import unittest
+import sys
+from unittest.mock import patch
+from azure_functions_worker.main import parse_args
+
+
+class TestMain(unittest.TestCase):
+
+    @patch.object(sys, 'argv',
+                  ['xxx', '--host', '127.0.0.1',
+                   '--port', '50821',
+                   '--workerId', 'e9efd817-47a1-45dc-9e20-e6f975d7a025',
+                   '--requestId', 'cbef5957-cdb3-4462-9ee7-ac9f91be0a51',
+                   '--grpcMaxMessageLength', '2147483647',
+                   '--functions-uri', 'http://127.0.0.1:50821',
+                   '--functions-worker-id',
+                   'e9efd817-47a1-45dc-9e20-e6f975d7a025',
+                   '--functions-request-id',
+                   'cbef5957-cdb3-4462-9ee7-ac9f91be0a51',
+                   '--functions-grpc-max-message-length', '2147483647'])
+    def test_all_args(self):
+        args = parse_args()
+        self.assertEqual(args.host, '127.0.0.1')
+        self.assertEqual(args.port, 50821)
+        self.assertEqual(args.worker_id,
+                         'e9efd817-47a1-45dc-9e20-e6f975d7a025')
+        self.assertEqual(args.request_id,
+                         'cbef5957-cdb3-4462-9ee7-ac9f91be0a51')
+        self.assertEqual(args.grpc_max_msg_len, 2147483647)
+        self.assertEqual(args.functions_uri, 'http://127.0.0.1:50821')
+        self.assertEqual(args.functions_worker_id,
+                         'e9efd817-47a1-45dc-9e20-e6f975d7a025')
+        self.assertEqual(args.functions_request_id,
+                         'cbef5957-cdb3-4462-9ee7-ac9f91be0a51')
+        self.assertEqual(args.functions_grpc_max_msg_len, 2147483647)
+
+    @patch.object(sys, 'argv',
+                  ['xxx', '--host', '127.0.0.1',
+                   '--port', '50821',
+                   '--workerId', 'e9efd817-47a1-45dc-9e20-e6f975d7a025',
+                   '--requestId', 'cbef5957-cdb3-4462-9ee7-ac9f91be0a51',
+                   '--grpcMaxMessageLength', '2147483647'])
+    def test_old_args(self):
+        args = parse_args()
+        self.assertEqual(args.host, '127.0.0.1')
+        self.assertEqual(args.port, 50821)
+        self.assertEqual(args.worker_id,
+                         'e9efd817-47a1-45dc-9e20-e6f975d7a025')
+        self.assertEqual(args.request_id,
+                         'cbef5957-cdb3-4462-9ee7-ac9f91be0a51')
+        self.assertEqual(args.grpc_max_msg_len, 2147483647)
+        self.assertIsNone(args.functions_uri)
+        self.assertIsNone(args.functions_worker_id)
+        self.assertIsNone(args.functions_request_id)
+        self.assertIsNone(args.functions_grpc_max_msg_len)
+
+    @patch.object(sys, 'argv',
+                  ['xxx', '--functions-uri', 'http://127.0.0.1:50821',
+                   '--functions-worker-id',
+                   'e9efd817-47a1-45dc-9e20-e6f975d7a025',
+                   '--functions-request-id',
+                   'cbef5957-cdb3-4462-9ee7-ac9f91be0a51',
+                   '--functions-grpc-max-message-length', '2147483647'])
+    def test_new_args(self):
+        args = parse_args()
+        self.assertEqual(args.functions_uri, 'http://127.0.0.1:50821')
+        self.assertEqual(args.functions_worker_id,
+                         'e9efd817-47a1-45dc-9e20-e6f975d7a025')
+        self.assertEqual(args.functions_request_id,
+                         'cbef5957-cdb3-4462-9ee7-ac9f91be0a51')
+        self.assertEqual(args.functions_grpc_max_msg_len, 2147483647)
+
+    @patch.object(sys, 'argv', ['xxx', '--host', 'dummy_host',
+                                '--port', '12345',
+                                '--invalid-arg', 'invalid_value'])
+    def test_invalid_args(self):
+        with self.assertRaises(SystemExit) as context:
+            parse_args()
+        self.assertEqual(context.exception.code, 2)