Conversations

Concrete instances of a conversation/interaction protocol shared between specific agents, typically tracked by a conversation-id and represented as a Coloured Petri Net or Dooley Graph marking in engines like ACRE. Conversations make protocol state first-class so plans can reason about whether a dialogue is in progress, completed, or stuck.

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Backlinks

ACRE Agent Conversation Reasoning Engine line 26

Linked Pages

Colored Petri Nets

Petri-net extension with typed tokens and arc expressions — common formalism for ACL conversation protocols.

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Conversation Protocols

Stateful, multi-turn interaction patterns (Contract Net, auction, query) specified as a finite automaton, Petri net, or role-based dialogue over performatives. Promote tractable ACL use by constraining expected message sequences, and are the unit on which ACRE’s reasoning engine operates.

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ACRE Agent Conversation Reasoning Engine

ACRE: Agent Conversation Reasoning Engine

Reference: Lillis & Collier (University College Dublin). Source file: ACRE_Agent_Conversation_Reasoning_Engine.pdf. URL

Summary

ACRE complements existing rule-based agent programming languages (AFAPL2, AgentSpeak, Jason, Jack) with explicit support for modelling, managing, and reasoning about complex multi-message conversations. Rather than handling each FIPA-ACL message individually, ACRE represents conversations as instances of protocols specified as Coloured Petri Nets or Dooley Graphs, so agents can track which performatives are expected next and react accordingly.

The paper integrates ACRE with the Agent Factory framework: conversations are exposed via a conversation-id parameter, and plan pre/postconditions in AFAPL2 reason over BELIEF(status(...)) predicates derived from ACRE. A Vickrey auction example shows how an Auctioneer agent uses ACRE-tracked conversations to issue cfp, collect propose/refuse messages, and broadcast accept-proposal/reject-proposal.

Key Ideas

Protocols are first-class citizens, separate from individual messages.
Conversations tracked via Coloured Petri Nets / Dooley Graphs.
Integration with AFAPL2: conversation state surfaces as beliefs for plan reasoning.
Code verification check that agent plans honour protocol expectations.
Vickrey auction case study using FIPA Contract Net-style interactions.

Connections

Conceptual Contribution

Claim: Agents need conversations, not just messages, as first-class abstractions; existing AOP languages (AgentSpeak, Jason, AFAPL2) lack native protocol reasoning.
Mechanism: Models FIPA-ACL interaction protocols as Coloured Petri Nets / Dooley Graphs instantiated per conversation-id; surfaces conversation state as BELIEF(status(...)) predicates usable in plan pre/postconditions; validated via Vickrey auction (Contract Net).
Concepts introduced/used: Interaction Protocols, Coloured Petri Nets, Dooley Graphs, Conversations, Conversation Policy, FIPA-ACL, Performatives, Contract Net Protocol, BDI, Agent-Oriented Programming, Multi-Agent Systems
Stance: engineering
Relates to: Operationalises the protocol-tracking needs implicit in FIPA-ACL and KQML; its plan-level conversation awareness is an ancestor of task/session tracking in modern Agent-to-Agent Protocol as covered by Survey Of Agent Interoperability Protocols.