Lead with consent, because you are not the owner
An ordinary boarding folder proves the cat is vaccinated and says who to call. Yours must also prove that you, a temporary carer, are entitled to hand this cat to a cattery or sitter at all. Put the owner's written consent at the front: a signed note or printed message authorising you to arrange boarding or sitting, naming any cattery or person the owner already approved, and — most importantly — authorising emergency veterinary treatment up to the limit the owner set, with their payment arrangement stated. Behind it, keep a copy of any power of attorney or care instruction the owner left for the deployment. A cattery that asks, quite properly, whether you may sign for someone else's cat should find the answer on page one.
Records in the owner's name, contacts that reflect deployment
The vaccination record, microchip registration, and insurance details will mostly be in the owner's name, so keep them exactly as issued and add a cover sheet explaining the arrangement rather than letting a cattery think the paperwork is wrong. The chip deserves a check of its own: if it still rings the owner's mobile, note beside it the number that should actually be called first while they are deployed, and whether the owner has updated the registry to you for the deployment period. Then build the contact list around communication reality — your number first, the owner's deployment contact route second with an honest note about how often it is checked, then any family member or unit family contact the owner named as the fallback decision-maker, then the vet.
The owner's vet, the owner's routine, written as they left it
Record the vet practice the owner chose and registered the cat with, even if another practice is closer to your home, because continuity of records matters and the owner may have prepaid or insured arrangements there. If an emergency forces a different vet, the folder should say so explicitly and give the registered practice's details for records transfer. The routine section should reproduce the owner's own instructions rather than your interpretation of them: the food they specified, the feeding times as they set them, any medication schedule with its administering notes, and the behaviours they flagged — the cat's reaction to carriers, to dogs, to being picked up — in their words where you have them. Where your own household has adapted things, mark clearly which lines are yours, so the next carer can tell the owner's baseline from temporary changes.
Plan for the stay extending and the carer changing
Deployment folders must survive two disruptions an ordinary folder never faces: dates moving, and the cat moving. Write down what happens if the owner's return is delayed beyond the boarding dates — who extends the booking, from what funds, and where the cat goes if the cattery cannot extend. Also assume the folder itself may travel: if you are posted elsewhere, fall ill, or the cat passes to another approved carer, everything that person needs must be inside it, including this consent chain, because a second-hand verbal summary of an absent owner's wishes is where mistakes breed. Keep a list inside the front cover of everyone who has held the folder and when, so the chain stays visible.
A packet that belongs to the cat, not to one house
That travelling quality is exactly what this cat needs from its records. KinsLe's Pet Passport keeps the pet's records together in one portable packet — vaccinations, chip details, vet, consent, and routine — ready for a cattery, a sitter, or a new temporary carer, so if the cat's care passes from your home to another, the owner's instructions and authority travel with the cat intact instead of being reconstructed from memory at each handover.