#1 - I'm not a native speaker, but I would insist that while it may well be both, since the person using it asks for an explanation, I think there may be readiness to accept this curt reaction if the explanantion is understandable.

Well, no, it's certainly not positive - I was hoping for neutral. I'm trying to find out if he was annoyed with me, so I'd like to avoid causing (further?) annoyance by implying he was rude.

I assume that each person might perceive these things a little differently, but I see calling someone "rude" as being somewhat harsher than calling them "curt." But they are both definitely based in criticism (to answer the OP question).

You can't get around this without implying a negative attitude from your interlocutor, but "brisk" maybe a more diplomatic way of expressing it.

If I needed to be careful or diplomatic, I might say that s/he had seemed/ been "a bit impatient" with me.

Re #6, me too -- 'barsch' was the first word that came to mind.

If your aim is to be tactful and not burn your bridges, then maybe something like ...

Do you have a minute? ...
This morning when I asked you about ..., you seemed very short with me. Were you just busy, or were you upset with me about something? (I'm sorry to have to ask, but since English isn't my native language, I want to make an extra effort to avoid misunderstandings. I really appreciate any advice you can give me.)

*f5* 'Impatient' is also good.

Impatient is more neutral than short. Saying "impatient" is the "nice" way of saying they were rude or curt (or short). IMO.

I don't think "curt" can ever be anything other than negative. It's never desirable.

But it is certainly possible to be curt for understandable reasons, isn't it?

#14: But it is certainly possible to be curt for understandable reasons, isn't it?

#15 - thx, that makes sense to me!

#17 - Well, I think it does in the way that one should avoid the word if one wants to sound neutral, as I deduct from some of the native speakers' comments.

#19 - deduce ≠ deduct, cool! Just learned to distinguish between two more words! :-)

In BE, to be short with someone is also negative.

Yes, Rrabbit, I see "short" as being essentially the same as "curt" in AE. I consider both of them to suggest a criticism.

In this case, I would opt for impatient rather than curt or short or brisk (OT - maybe "brusque" was meant for "brisk") -- it's a politer way of describing the interaction, since it directs any implicit criticism towards yourself rather than towards your interlocutor.

I agree, Martin.

#23: maybe "brusque" was meant for "brisk"

Obviously in the OP the word is meant negatively, or the question would not have been asked in the first place. But if you were talking about two third parties, and said that A was pretty curt towards B, and you took the side of A, regarding B's request or attitude as unreasonable, then it would be positive. The word itself is neutral. We're talking about pragmatics here, not semantics.

#27: I don't think politeness is the issue when it comes to communication between subordinates and superiors, or even equals, in a military context. It would be impolite to breach that protocol, though.

I would argue that "direkt" is akin to "curt".