Is a trans person obligated to tell someone they're trans before having casual sex, if the person thinks they're a cis person of their AGAB?

I'm sure most people would say it should always be said if they're a stealth trans person. But what if they're medically transitioning yet don't pass?

Edit: Not gonna lie, it surprised me how many people misunderstood the question and said that a fully transitioned person shouldn't have to disclose.

I remembered this sub being a lot more "if you don't tell them you're trans you are RAPING them!", so I guess it makes me a little glad?

I wonder if all the transphobic trolls have quit the sub now that they can't gaslight us that "no one is trying to take away ur rights" or whatever