What is the contract net protocol?

The contract net protocol is a decentralized method for allocating tasks among agents. An agent with a task to delegate announces it, other agents submit bids reflecting their ability to perform it, and the announcer awards the task to the best bidder. It mimics a simple market for distributing work.

What is the difference between coordination and cooperation?

Coordination is about managing the interdependencies between agents' actions so they do not conflict and fit together, which can matter even among competitors. Cooperation specifically means agents working together toward shared or compatible goals. Cooperation typically requires coordination, but coordination alone does not imply shared goals.

Agent Coordination and Cooperation

Agent coordination and cooperation concern how multiple autonomous agents align their actions to avoid conflict and work together toward shared or compatible goals.

Definition

Coordination is the management of interdependencies between agents' activities so they fit together, and cooperation is agents working together toward common or compatible goals, achieved through communication, negotiation, and shared commitments.

Scope

This topic covers the mechanisms by which agents coordinate and cooperate: agent communication languages and speech-act-based messaging, negotiation and task allocation protocols such as the contract net, teamwork and joint intentions, social conventions and norms, and coalition formation. It addresses how agents reach agreements, divide labor, and maintain coherent joint behavior under decentralization. The strategic, equilibrium-level analysis of incentives is treated under game theory and mechanism design.

Core questions

How do agents communicate intentions and information in a shared language?
How are tasks allocated among agents through negotiation or bidding?
How do agents form and maintain joint commitments to act as a team?
How do social conventions and norms reduce the need for explicit coordination?

Key concepts

agent communication languages
speech acts
negotiation
contract net protocol
task and resource allocation
joint intentions and teamwork
social conventions and norms
coalition formation

Key theories

Agent communication and speech acts: Agent communication languages model messages as speech acts (requests, informs, proposals) with defined meanings, giving agents a principled basis for exchanging information and intentions to coordinate behavior.
Contract net protocol for task allocation: In the contract net protocol, a manager announces a task, agents bid based on their suitability, and the manager awards the contract, providing a decentralized, market-like mechanism for distributing work among agents.
Joint intentions and teamwork: Formal theories of intention and joint commitment specify what it means for agents to act as a team, including obligations to inform teammates when goals become unachievable, underpinning robust cooperative behavior.

Clinical relevance

Coordination and cooperation methods underlie cooperative robotics and multi-robot teams, distributed scheduling and logistics, supply-chain coordination, sensor networks, and collaborative software agents, enabling decentralized systems to achieve coherent collective behavior.

History

Coordination and cooperation emerged as core concerns of distributed AI in the 1980s, with Smith's contract net protocol (1980) a landmark in decentralized task allocation. The 1990s formalized agent communication languages and theories of joint intention and teamwork, which remain central to building cooperative multi-agent systems.

Key figures

Michael Wooldridge
Reid G. Smith
Philip R. Cohen
Hector J. Levesque
Nicholas R. Jennings

Seminal works

smith1980
cohen1990
wooldridge2009

Frequently asked questions

What is the contract net protocol?: The contract net protocol is a decentralized method for allocating tasks among agents. An agent with a task to delegate announces it, other agents submit bids reflecting their ability to perform it, and the announcer awards the task to the best bidder. It mimics a simple market for distributing work.
What is the difference between coordination and cooperation?: Coordination is about managing the interdependencies between agents' actions so they do not conflict and fit together, which can matter even among competitors. Cooperation specifically means agents working together toward shared or compatible goals. Cooperation typically requires coordination, but coordination alone does not imply shared goals.