No etiquette exists for this yet. The technology moved faster than any shared understanding of what it means, so the question feels far heavier than the activity really is.
What follows is not a rulebook. It is a handful of distinctions that make the decision easier.
One test that covers most cases
Drop the debate about whether it is "cheating" or "weird." Those arguments never end, and people mostly use them to defend a conclusion they already reached.
Try this instead: would I be fine with it being discovered rather than disclosed?
If yes, you are using software and there is nothing to confess. If no, that discomfort is telling you something. It does not necessarily mean you are doing wrong. It means you have decided the app carries a meaning you have not said out loud.
This one question settles the partner situation more reliably than any argument over categories.
With a partner
The best reason to speak up is a plain one: being found out is worse than telling, every time. An unlocked phone, a notification on the lock screen, a charge on a joint bank statement. See payment privacy and using a shared device for the practical side, though no setup removes the risk completely.
If you bring it up, two things help.
Start with what it is, not with a defense. "I've been trying one of those AI chat apps, kind of like a game" opens a conversation. Explaining unprompted why it means nothing opens an interrogation.
Listen for the question underneath. It is rarely about the app. It is usually "is something missing for you?" That deserves a real answer, not reassurance about the technology.
Sometimes the honest answer is yes, something is missing. Good to know, and not the app's doing.
With friends
The stakes run lower than most people assume. Curiosity is the typical response ("what's it actually like?"), because plenty of people have read about the category and never tried it.
A short, honest description does the job: it is entertaining, it is like a novel you can talk to, and it costs about what a streaming service does.
People who react badly are usually reacting to a stereotype about loneliness, not to you. That deserves its own look, but it is no reason to lie.
At the office
Don't.
Stigma is not the point. The point is what employers can see. A work laptop is managed hardware, the network is monitored, and none of that is yours to negotiate. Keep this off employer devices entirely. The reasoning is in using a shared device.
Wording that helps
Name the activity, not the relationship. "I use an AI chat app" lands very differently than "I have an AI girlfriend," and both are true. The first invites a question. The second invites a verdict.
Also say what you get out of it in everyday terms: it is relaxing, it is fun to write with, it fills a quiet evening. Those are ordinary reasons to do something, and presenting them as ordinary is usually honest as well as effective.
Where the uncomfortable part is
One case is worth pulling out, because plain talk serves you better than comfort.
Suppose you avoid mentioning it specifically because you know you are using it in place of something else: returning a call, going out, tackling a task. Then the hesitation points at the substitution, not the app. That is the signal the boundaries piece is about, and it is better to catch it early than late.
Most people are not in that situation. Most use one of these apps a few evenings a week, and the only awkwardness is conversational, which fades fast.
A line that tends to work
"It's a chat app with a character, it helps me unwind, and I'd rather you hear it from me than stumble on the subscription."
It is direct and unapologetic, and it shows you were thinking of them, which is usually the whole point of the question.
