FIPA-ACL heritage — what 2026 protocols keep and drop
FIPA-ACL (2000)
~20 performatives
inform · request · query-if · query-ref
propose · accept · reject · cfp
subscribe · cancel · failure · agree
SL0/SL1 content languages
formal ontology required
JADE / JACK reference platforms
what faded
ontology overhead
Java/commercial runtimes
SL semantics no one used
non-web transport
the web stack won
REST · JSON-RPC · gRPC
2026 successors
MCP · A2A · ACP · ANP · NLIP
JSON-native payloads
natural-language content
HTTP · SSE · WebSocket
self-describing discovery
looser semantics, easier wire
Performative → 2026 equivalent
request
MCP tools/call · A2A POST /tasks
query-ref
MCP resources/read · A2A GET /tasks/{id}
subscribe
A2A SSE task events · MCP subscriptions/listen
cfp
task-market broadcast (bid solicitation)
propose · accept · reject
bidder response · manager award/decline
cancel
A2A task cancellation · MCP cancellation notification
inform · failure
artifact push · error object in JSON-RPC response
kept: envelope + intent + correlation · dropped: SL semantics + mandatory ontology