as result - items in the real host does not start to monitor because it has no interface in the DB.
Host availability is marked as "Invalid port number []"

Item created by zabcon.
Request:
raw json {"auth":"$auth","method":"item.create","id":163,"params":

{"hostid":10098,"type":0,"value_type":3,"delay":60,"history":10,"description":"Test key created by API","key_":"test.echo[my_test_text]"}

,"jsonrpc":"2.0"}
Answer:
{:class=>:raw, :result=>{"itemids"=>["25447"]}}

DB (item in the host):
mysql> SELECT `key_`, `description`, `interfaceid` FROM `items` WHERE `itemid` =25449;
-----------------------------------------------------------

-----------------------------------------------------------

-----------------------------------------------------------
1 row in set (0,00 sec)