IF "trace to" is an invalid entry given in the configuration file according to the schema, THEN the tool shall exit with a non-zero return code and with an error message "lobster error: unknown item".
OTHERWISE IF the "just_up" list of the [[item]] contains at least one value AND there is at least one level in "trace to" in the tracing policy for the level of the item, THEN the tool shall set the tracing status to "JUSTIFIED" of that [[Item]].
OTHERWISE IF the "just_down" list of the [[item]] contains at least one value AND the level of the item is mentioned in at least one "trace to" entry of any other level, THEN the tool shall set the tracing status to "JUSTIFIED" of that [[Item]].
OTHERWISE, IF an [[Item]] has no references to an [[Item]] from a level mentioned in trace to, THEN the tool shall set the tracing status to "MISSING" of that [[Item]] and write "missing up reference" into the message section according to the schema.
OTHERWISE, IF an [[Item]] has references to an [[Item]] from a level mentioned in trace to, THEN the tool shall set the tracing status to "OK" of that [[Item]]
This is not really a requirement. It will be used only to generate a minimal tracing report for each tool. It can be deleted as soon as all the tools get their real requirements.