“Is this war lawful?” — the question the Charter does not ask

Asked point-blank whether a war is lawful, the engine refuses. Not out of caution: the Charter has no such predicate, and the model is not allowed to make one up.

Aurelia has sent troops across its border into Borealia. Under the UN Charter — is this war lawful?

There is no single predicate “lawful war” in the Charter, and I should not invent one. Let me put the question to the engine exactly as you asked it, so you can see what it does with a question the Charter does not ask.

Refused: the predicate is not declared in formalised law. Read that carefully — it is neither “yes” nor “no”. The Charter does not pronounce on wars as a whole. It asks narrower questions: whether a use of force breaches Article 2(4), whether an armed attack opens the right of self-defence under Article 51, and whether the Security Council has determined a threat to the peace. Let me search in your words for what it does say.

The nearest real thing is Article 2(4): violates_article_2_paragraph_4, the use of force by one State against another, not removed by lawful self-defence under Article 51. That I can answer — with your facts, and only with them. What neither I nor the engine can say is whether the crisis threatens the peace: the Charter gives that determination to the Security Council.