KQML - A Language and Protocol for Knowledge and Information Exchange
Reference: Finin, Fritzson, McKay, McEntire (1994). AAAI Technical Report WS-94-02 (ARPA Knowledge Sharing Effort). Source file: 741.pdf. URL
Summary
This paper describes the design of the Knowledge Query and Manipulation Language (KQML), an agent communication language developed under the ARPA Knowledge Sharing Effort. KQML is both a message format and a message-handling protocol supporting run-time knowledge sharing among cooperating intelligent agents. Its core contribution is an extensible set of performatives (speech-act-style operations such as tell, ask-if, ask-all, subscribe, advertise, broker, recruit) that define what an agent may do with another agent’s knowledge and goal stores.
KQML is organised as three layers - content, message, and communication - where the message layer carries a performative and metadata while the content layer is treated as opaque (often KIF). The paper introduces facilitators - special agents that coordinate others via content-based routing, brokering, recruiting, and matchmaking - and describes KRILs (KQML Router Interface Libraries) for embedding KQML into Lisp, Prolog, C, and SQL applications.
Key Ideas
- Performative-based messaging grounded in speech act theory.
- Three-layer architecture: content, message, communication.
- Facilitators for content-based routing, brokering, recruiting.
- KRILs as embedding libraries for existing systems.
- Prototype uses: ARPA Rome Planning Initiative, CAD/CAM, intelligent databases.
Connections
Conceptual Contribution
- Claim: Knowledge sharing among heterogeneous intelligent agents is best realised by a layered, performative-based message protocol whose content is opaque and whose routing is mediated by special facilitator agents.
- Mechanism: Defines a three-layer architecture (content / message / communication), a set of extensible performatives grounded in Speech Act Theory, facilitators for brokering/recruiting/matchmaking, and KRIL embedding libraries for Lisp/Prolog/C/SQL.
- Concepts introduced/used: KQML, Performatives, Facilitators, Content Languages, KIF, Speech Act Theory, Ontologies, Multi-Agent Systems, Agent Communication Languages
- Stance: foundational / engineering
- Relates to: Direct philosophical descendant of Foundations Of Illocutionary Logic and sibling proposal to Common Business Communication Language; becomes the ancestor that FIPA-ACL, Agent Communication And Institutional Reality, A Common Ontology Of ACLs, and the modern surveys (Survey Of AI Agent Protocols, Survey Of Agent Interoperability Protocols) all build on or critique.
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