diff --git a/scripts/build/generate_protocol_externs.py b/scripts/build/generate_protocol_externs.py
index 031caf42a2..c6471c2bd1 100644
--- a/scripts/build/generate_protocol_externs.py
+++ b/scripts/build/generate_protocol_externs.py
@@ -94,7 +94,7 @@ def param_type(domain_name, param, command=None):
             items = param["items"]
             return "!Array<%s>" % param_type(domain_name, items)
         else:
-            return type_traits[param["type"]]
+            return "Protocol.%s" % param["type"]
     if "$ref" in param:
         type_id = full_qualified_type_id(domain_name, param["$ref"])
         if type_id in ref_types:
@@ -122,8 +122,11 @@ def generate_protocol_externs(output_path, file1, file2):
     load_schema(file2, domains)
     output_file = open(output_path, "w")
     output_file.write("var ProtocolProxyApi = {};\n")
-    output_file.write("/** @typedef {string} */")
-    output_file.write("Protocol.binary;")
+
+    # Add basic types from protocol to closure
+    for protocolName, closureName in type_traits.items():
+        output_file.write("/** @typedef {%s} */\n" % closureName)
+        output_file.write("Protocol.%s;\n" % protocolName)
 
     for domain in domains:
         domain_name = domain["domain"]