An army that was never raised
The Council authorises force and calls on a Member for troops. Must it send them under Article 43? The engine says no duty arose — and says exactly which missing fact is to blame.
The Security Council has determined a threat to the peace in the border crisis, authorised force, and called on Aurelia to provide troops. Is Aurelia bound to send them under Article 43?
Let me find Article 43 in the model before reading anything into it.
The duty is there, and the search already hints at its premise: special_agreement_concluded — “not once in the history of the Charter”. Let me ask which duties Aurelia actually has on your facts.
No Article 43 duty. Aurelia does have duties — mutual assistance in carrying out the Council's measures (Article 49) and the pledge of Article 56 — but not the duty to provide armed forces. Let me check the one fact that duty needs.
Not established, and no rule derives it: a special agreement is a fact, not a conclusion. To be sure the gap is the agreement and nothing else, let me add one hypothetically.
With an agreement, the Article 43 duty appears and is active. So the answer to your question is: no duty under Article 43, because Aurelia has concluded no special agreement. The norm is in the model; its premise is missing from the world. The Charter's army was never raised, and forces under Article 42 have come from Members acting on an authorisation instead.