Paper Submission to: IJCAI-99 Workshop on Agent Communication Languages An Approach to using XML and a Rule-based Content Language with an Agent Communication Language Benjamin N. Grosof IBM T.J. Watson Research Center 30 Saw Mill River Road, Hawthorne, NY 10532, USA grosof@us.ibm.com (alt.: grosof@cs.stanford.edu)\ http://www.research.ibm.com/people/g/grosof/ (914) 784-7783 ; -7455 fax Yannis Labrou Electrical Engineering and Computer Science Department University of Maryland, Baltimore County; Baltimore, MD, 21250, USA jklabrou@cs.umbc.edu http://www.cs.umbc.edu/~jklabrou/ (410) 455-3624 March 15, 1999 We argue for an XML encoding of FIPA Agent Communication Language (ACL), and give an alpha version of it, called Agent Communication Markup Language (ACML), which we have implemented. The XML approach facilitates developing/maintaining parsers, integrating with WWW-world software engineering, and the enriching capability to (hyper-)link to ontologies and other extra information. The XML approach applies similarly to KQML as well. Motivated by the importance of the content language aspect of agent communication, we focus in particular on business rules as a form of content that is important in e-commerce applications such as bidding negotiations. A leading candidate content language for business rules is Knowledge Interchange Format (KIF), which is currently in the ANSI standards committee process. We observe several major practical shortcomings of KIF as a content language for business rules in e-commerce. We argue instead for a knowledge representation (KR) approach based on Courteous Logic Programs (CLP) that overcomes several of KIF's representational limitations, and argue for this CLP approach, e.g., for its logical non-monotonicity and its computational practicality. CLP is a previous KR that expressively extends declarative ordinary logic programs cf. Prolog; it includes negation-as-failure plus prioritized conflict handling. We argue for an XML encoding of business rules content, and give an alpha version of it, called Business Rules Markup Language (BRML), which we have implemented. BRML can express both CLP and a subset of KIF (i.e., of first-order logic) that overlaps with CLP. BRML expressively both extends and complements KIF. Future work includes extending this XML content language expressively in multiple directions. One such direction is to cover full KIF; another is to incorporate semantically-clean procedural attachments, cf. the existing Situated Logic Programs KR; a third is to expressively generalize the Courteous LP conflict handling aspects . The overall advantages of an XML approach to content language are similar to those for the XML approach to ACL, and indeed complements the latter since content is carried within ACL messages.