Start with lived history, not the label
A card that says good with cats can mean very different things. For one rescue cat it means she curled up with a bonded companion for years. For another it means she ignored cats in neighboring kennels during a short shelter stay. Your first questions should pin down which version applies to the cat in front of you. Ask whether she has ever lived in a home with other cats, for how long, and what that daily life looked like at feeding time, at the litter boxes, and overnight when people were not refereeing.
Ask about introductions she has already done
How a cat handled past introductions predicts more than a single meet-and-greet. Ask how she was introduced to feline roommates in foster care or at the shelter: through a closed door, through a baby gate, or straight into shared space. Ask how many days passed before she ate calmly nearby, stopped hissing, or chose to approach. A cat who needed a week of scent swapping and then settled is a very different prospect from a cat who has never progressed past barrier contact, even if both are described as fine with cats.
Probe the friction points specifically
General friendliness hides the moments that actually break multi-cat homes. Ask directly about food guarding around bowls, chasing during nighttime play, blocking access to litter boxes or favorite perches, and staring standoffs that staff had to interrupt. Ask whether she prefers male or female companions, kittens or calm adults, and whether a confident cat or a shy cat brought out her best behavior. Also ask what she does when she wants space: a cat who walks away is easier to house with others than one who swats first and retreats second.
Ask what your home needs to provide
Turn the conversation toward fit. If your resident cat is elderly and slow-moving, ask whether this rescue cat has lived with a senior before or whether her play style is boisterous enough to overwhelm one. Ask how many litter boxes and separate feeding stations the rescue recommends for the pairing, and whether they suggest a full room separation to start. Their willingness to discuss a staged plan, and to share notes from foster carers who watched her with other cats day to day, tells you how much real observation sits behind the label.
Plan the introduction before you commit
If the answers sound grounded, agree on what the first two weeks will look like: a separate room, scent swapping with bedding, short visual contact, then brief supervised time together if meals on opposite sides of a door stay relaxed. Ask whether the rescue will take your call if tension escalates and what signs they would consider a genuine mismatch rather than normal adjustment. Writing that plan down while it is fresh keeps everyone in the household consistent about doors, feeding spots, and who supervises. KinsLe Family Sharing helps that consistency hold, because the new cat's profile, quirks, and introduction notes sit alongside your resident cats' details where every family member can see them.