Does Mark spend my ad budget automatically?

No. Mark is built so that you are always in control of your money, and there are three layers protecting you.

Nothing runs until you turn it on

Everything Mark creates, including campaigns, ad sets, and ads, is created paused. Paused ads exist in your account but do not deliver and do not spend.

You are the one who switches it on

Mark does what you ask it to, so a clear instruction gets carried out without a second round of approval. What it cannot do is make something live. Turning a campaign, ad set, or ad on is always your call, from the created objects panel in the chat or from Manage Ads.

You set the budget, Meta charges it

You set and approve the budget, and Meta charges that spend directly to the payment method on your Meta account. Mark never moves money on its own and is never a party to the payment.

The result is simple: a campaign only starts spending when you turn it on from Manage Ads, with a budget you approved.