A formal specification language for agent conversations

Abstract

Agents interact in the context of a society to exchange knowledge, to cooperate and to coordinate their activities. A standard approach is to describe these interactions as conversations specified by means of interaction protocols (IPs). The set of conversations in which an agent can participate defines its communication interface. Therefore, the standardised sets of IPs that specify these conversations can be viewed as Agent Interface Definitions (AID), just as procedure and function definitions make up programming interfaces (API) in other programming paradigms. This paper presents the abstract syntax and semantics of ACSL1: a new formal specification language that can clearly and precisely describe these interfaces so that they can be consumed both by designers and programmers (generally using CASE tools) and automatically by actual agents during interaction. This language fills a gap in the development of agent interface definition languages (AIDL). The paper focuses particularly on the newest features of the language, like (1) protocol composition, (2) protocol exceptions related to the reception of out-of-sequence messages or timeout expirations, (3) compensation protocols that adapt the classical concept of transaction to the autonomy and rationality of agents and, finally, (4) specification of message correlation and causality.