Agent Communications Language

Agent Communication Language (ACL) consists of computer communication protocols that are intended for AI agents to communicate with each other.

In 2007, protocols of this nature were proposed which include:

After the surge in generative AI based on the use of Large language models and the advent of Agentic AI, new protocols emerge in this area as the Natural Language Interaction Protocol (NLIP) or the Agent2Agent open protocol. NLIP is an application-level communication protocol defined between AI Agents or between a human and an AI agent. Ecma International; a standards body which develops and publishes international standards for the information and communication industry; published on 10 December 2025 five new standards and one technical report defining the Natural Language Interaction Protocol (NLIP).

As a result, we can define agent communication protocols into two categories: ontology based agent communication protocols and generative AI based agent communication protocols.

Ontology based agent communication protocols use a common ontology to be used between agents. An ontology is a part of the agent's knowledge base that describes what kind of things an agent can deal with and how they are related to each other. FIPA-ACL and KQML are examples of such protocols. These protocols rely on speech act theory developed by Searle in the 1960s and enhanced by Winograd and Flores in the 1970s. They define a set of performatives, also called Communicative Acts, and their meaning (e.g. ask-one). The content of the performative is not standardized, but varies from system to system. Implementation support of FIPA-ACL is included in FIPA-OS and Jade.

Generative AI based agent communication protocols such as NLIP do not require a shared ontology among communicating agents. In its stead, they use generative AI models to translate natural language text, images, videos or other modalities of data into a local ontology. This provides for hot-extensibility where the same protocol can be used for multiple communication needs, and simplifies version control since different agents can use different versions of a shared ontology. NLIP has been designed with security considerations in mind. The specification and standards comprising NLIP are developed and maintained by Ecma Technical Community 56.

References

  1. ↑ Poslad, Stefan (2007). "Specifying Protocols for Multi-agent System Interaction". ACM Transactions on Autonomous and Adaptive Systems. 2 (4): 15–es. doi:10.1145/1293731.1293735. S2CID 9477595.
  2. ↑ Finin, Tim; Richard Fritzson, Don McKay and Robin McEntire (1994). KQML as an agent communication language. Proceedings of the third international conference on Information and knowledge management, CIKM '94. pp. 456–463.
  3. ↑ Aiyagari, Sanjay; Bertino, Elisa; Bieniek, Jan; Chiou, Yan-Ming; Dodhiawala, Raj; Hughes, Sean; Jamin, Sugih; Kundu, Ashish; Lenchner, Jon; Mauriello, Matthew; Ratnaparkhi, Abhay; Rahouti, Mohamed; Sheffler, Tom; Shen, Chien-Chung; Verma, Dinesh C. (2025-05-21). "Natural language interaction protocol (NLIP)". In Wysocki, Bryant T.; Blowers, Misty (eds.). Disruptive Technologies in Information Sciences IX. SPIE. p. 13. doi:10.1117/12.3054059. ISBN 978-1-5106-8749-3.
  4. ↑ "Ecma International approves NLIP standards suite for universal AI agent communication". ecma-international.org. Ecma International. Retrieved 17 December 2025.
  5. ↑ Searle, J.R. (1969). Speech Acts. Cambridge University Press, Cambridge, UK.
  6. ↑ Poslad, Stefan; Philip Buckle and Robert Hadingham (2000). The FIPA-OS agent platform: Open Source for Open Standards. Proceedings of 5th International Conference on the Practical Application Of Intelligent Agents And Multi-Agent Technology (PAAM). pp. 355–368.
  7. ↑ Poslad, S; Buckle P, Hadingham R.G (2001). "Open Source, Standards and Scaleable Agencies". Infrastructure for Agents, Multi-Agent Systems, and Scalable Multi-Agent Systems. Lecture Notes in Computer Science. Vol. 1887. pp. 296–303. doi:10.1007/3-540-47772-1_30. ISBN 978-3-540-42315-7.
  8. ↑ Bellifeminee, Fabio; Agostino Poggi and Giovanni Rimassa (2001). JADE: a FIPA2000 compliant agent development environment. Proceedings of the fifth international conference on Autonomous agents. pp. 216–217.
  9. ↑ "NLIP Project". nlip-project.org. Retrieved 2025-05-27.
  10. ↑ Aiyagiri, Sanjay. "Security design for NLIP: a universal protocol for AI-enabled systems". spie.org. Retrieved 2025-05-27.{{cite web}}: CS1 maint: url-status (link)
  11. ↑ "NLIP: Redefining Secure Communication Between Natural Language AI Models". www.linkedin.com. Retrieved 2025-05-27.
  12. ↑ "NLIP Security Guidelines and Best Practices". nlip-project. Retrieved 25 December 2025.
  13. ↑ "TC56". Ecma International. Retrieved 2025-05-27.