White RoomNEW

Verbs Promise Nothing

A client retries any request that times out, up to three times. Four handlers:

# request server-side effect
a POST /orders inserts an order row with a freshly generated id
b PUT /carts/9/items appends the item in the body to the cart's item list
c PUT /users/42/email sets the email column to the value in the body
d PATCH /counters/7 body {"op":"add","value":1} increments the counter by 1

Which handler is idempotent in the RFC 9110 sense, so that three deliveries leave the same state as one?