Cat Doors & Enclosures: what Claude and GPT would buy

Check before you buy

• Opening size vs. the cat. Measure your cat's widest point (usually the shoulders) and its height from belly to back, then choose a flap opening larger than both. Large breeds such as Maine Coons often will not fit standard openings and may refuse a tight flap.
• Selective entry. If unwanted cats are a concern, choose a microchip- or tag-reading flap. Check that it reads your cat's chip type. Magnetic and manual flaps let in any animal that pushes them.
• Install surface and thickness. Check which surfaces the flap supports (door, wall, glass). For walls or thick doors, look for an available tunnel extension of the right depth. A door-only flap cannot be fitted to brick, and glass needs a round cut by a glazier.
• Locking modes. Prefer four modes: in only, out only, open, locked. Curfew or timer modes are useful for night lock-in. Being able to keep cats inside at night or at the vet's request is the most-used feature after entry.
• Draft and weather sealing. Look for a brush or magnetic seal around the flap and a tight-closing frame. Poorly sealed flaps leak heat and rattle in the wind.