Creativity · Agent Protocol
FIPA ACL — Agent Communication Language (historical)
FIPA ACL (Agent Communication Language) is the IEEE/FIPA standard for inter-agent messaging, ratified in the late 1990s and early 2000s. Built on speech-act theory and the KQML tradition, ACL defines performatives — inform, request, propose, agree, refuse — that let autonomous agents negotiate intent rather than just exchange data. It shaped every modern A2A protocol even as the market moved on from symbolic agents.
Protocol facts
- Sponsor
- FIPA / IEEE (historical)
- Status
- deprecated
- Spec
- http://www.fipa.org/repository/aclspecs.html
- Interop with
- KQML, JADE
Frequently asked questions
Is FIPA ACL still used?
In mainstream LLM-agent stacks, no. Its direct heirs are academic multi-agent frameworks like JADE. But FIPA's speech-act vocabulary — inform, request, propose, accept, reject — recurs throughout A2A, ACP, and even tool-calling designs.
What is a 'performative' in FIPA ACL?
A performative is the communicative intent of a message — not the data, but the type of act. 'Request' means 'I am asking you to do X'; 'inform' means 'I am asserting X is true.' Borrowed from Searle's speech-act theory.
Why did FIPA ACL fall out of fashion?
It presupposed symbolic reasoning agents with shared ontologies — a world that never quite arrived. LLM-era agents speak natural language plus tool calls, so the elaborate performative grammar was overkill for most use cases.
Sources
- FIPA ACL specifications — accessed 2026-04-20