Tarot is a tool, and like every tool it does some things well and other things badly. Knowing which is which makes you a better reader and a better client.
Here is what a reading can't do.
It can't tell you what someone else is thinking. The cards in front of you reflect your relationship to the question, not the inside of someone else's head. When I pull cards about a relationship, I'm reading you — your part of it, your energy in it, what's possible from where you are now. Not them. I won't tell you whether your ex still loves you. I will tell you what your part of the loop has been.
It can't tell you what's going to happen next Tuesday. Tarot doesn't work that way. It can show you trajectories — where the current trend is heading if you stay the course — but the moment you change a choice, you change the path. The cards reflect a moment. The moment changes.
It can't make a decision for you. The cards can lay out the energies of two options. They can show you what each path holds. They can name what's underneath the surface choice. But the choosing is yours. If you come to a reader hoping to be told what to do, you'll leave disappointed by the good readers and lied to by the bad ones.
It can't fix a problem the cards don't see. The cards reflect what's already moving. If you ask about a situation and the cards don't mention an obvious player or factor — your mom, your boss, the lease — that's worth noting, but it doesn't mean those things aren't real. The cards aren't omniscient. They're focused.
It can't override what your body already knows. If the reading says yes and your stomach says no, the stomach wins. Always. The cards are a mirror, not an oracle. A good reading agrees with what you already half-knew. A great reading makes the half-knowing speakable.
It also can't replace a therapist, a doctor, a lawyer, an accountant, or a friend who will actually listen to you. It can sit alongside any of those. It is not any of them.
Know what the tool does. Use it for what it does. Don't ask the screwdriver to be a hammer.