Creativity · Agent Protocol
AI Engineer Foundation Agent Protocol (aka Arcadia)
The AI Engineer Foundation Agent Protocol — sometimes discussed under the Arcadia project banner — is an open, vendor-neutral REST specification for talking to an agent as a service: create a task, list steps, stream outputs, fetch artifacts. It was spun out of the AutoGPT-era 'agent benchmark' community and is the closest thing the open ecosystem has to a simple, HTTP-first agent runtime protocol. It deliberately overlaps minimally with MCP (tools) and A2A (agent-to-agent discovery) — it governs how a human or system operates a single agent.
Protocol facts
- Sponsor
- AI Engineer Foundation (open community)
- Status
- proposed
- Spec
- https://github.com/Significant-Gravitas/AgentProtocol
- Interop with
- MCP, A2A, AutoGPT, Hugging Face Agents
Frequently asked questions
How does it differ from A2A?
A2A governs agent-to-agent discovery and task handoff across independent agents. The Agent Protocol governs how a caller (UI, other system) runs and inspects a single agent — it's operator-to-agent, not peer-to-peer.
Is anyone using this in production?
Adoption is niche compared with OpenAI Agents SDK or LangGraph APIs, but it's used in benchmarks and OSS research projects because its simple REST surface is easy to implement against any agent framework.
Is the project still active?
The spec repo saw steady maintenance into 2025 and influenced the design of A2A and similar efforts. Activity has slowed as larger-sponsor protocols consolidate, but it remains a useful lightweight option.
Sources
- Agent Protocol — Significant Gravitas repo — accessed 2026-04-20
- AI Engineer Foundation — accessed 2026-04-20