Tech Reports


CATP: A Communication Protocol for CAT Games (version 2.0)

Jinzhong Niu, Albert Mmoloke, Peter McBurney and Simon Parsons


The Trading Agent Competition (TAC) Market Design Tournament, also known as the CAT Tournament, supports multiple markets, each regulated by a specialist, that run in parallel and compete against each other to attract traders and make profit. Each entrant of the CAT Tournament runs a specialist, and sets the market rules so as to win the game according to a certain set of assessment criteria. The game between specialists is also commonly called a CAT game.

This document presents the specification of the communication protocol for interactions between a CAT server and CAT clients either specialists or traders in CAT games. The protocol is denoted as the CAT Protocol, or in short CATP. The open-source JCAT project provides the software platform for CAT games and an API in Java for entrants to build their market mechanisms (specialists). The API abstracts away the low-level communication details illustrated in this document, so reading this document is only necessary if it is desired to build a CAT client from scratch or to do so in a programming language other than Java.

The document is version 2.0 of the CATP Protocol Specification, and is issued on 30 April 2009. It replaces version 1.19, which was issued on 12 June 2008. Version 2.0 of this document is issued as University of Liverpool Department of Computer Science Technical Report ULCS-09-012. This document should be read in conjunctiom with the CAT Overview document, which was issued as University of Liverpool Department of Computer Science Technical Report ULCS-09-005, available from

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