1. A descriptor repository comprising one or more computers, wherein the one or more computers are configured to perform operations for: receiving a descriptor label for a merchant, wherein the descriptor label comprises a merchant name, a merchant address, a merchant telephone, a merchant location, a merchant slogan, a merchant operating name, or a combination thereof, and wherein the descriptor label identifies financial transactions associated with the merchant; identifying at least one descriptor definition that maps to the descriptor label, wherein the at least one descriptor definition provides supplementary contextual information for the financial transactions associated with the descriptor label for a respective merchant, and comprises information directly received from a source other than the merchant, is not included in the descriptor label, and further describes the identified financial transactions associated with the descriptor label; storing the at least one descriptor definition in a database; receiving, from a network, a request for additional information associated with a transaction; identifying one or more of the descriptor definitions based on a comparison of at least a portion of information for the transaction with the descriptor labels associated with the one or more descriptor definitions, wherein one or more of the descriptor definitions includes at least one descriptor definition; and transmitting, to the network, a response including the one or more descriptor definitions.