Atomic claiming: two tractors never clear the same lot

The problem with a busy fleet

When many machines are choosing their own next property at the same moment, two of them can eye the same lot in the same second. If both start driving to it, you get wasted trips, an angry customer with two tractors in one driveway, and a hole somewhere else.

Snowmass makes that impossible.

One claim, decided by the database

Every property can be owned by exactly one deployment at a time. When a tractor tries to claim a property, Snowmass performs a single atomic database operation that only succeeds if the property is still unclaimed. The database itself is the referee:

• If the operation reports one row changed, the claim succeeded — the property is yours.
• If it reports zero rows changed, a peer got there a heartbeat earlier — you lost the race cleanly and the engine instantly hands you the next best property instead.

There is no "check, then claim" gap for two machines to slip through. The check and the claim are the same indivisible step, so a property can never be booked twice.

Why it matters

• No double-dispatch — never two machines sent to one lot.
• No collisions under load — the guarantee holds whether five tractors are running or fifty, and whether GPS pings arrive milliseconds apart.
• No manual deconfliction — a dispatcher never has to spot and untangle a double-booking, because one can't happen.

This is the quiet foundation under everything else in the swarm: because claiming is race-free, machines can decide independently and still act as one coordinated fleet.