# Agent Interop & Transport

> how agents talk to each other

_5 of 28 · [all The Agent Protocol Atlas](/protocols)_

- [A2A](/protocols/interop/a2a) — The leading standard for agent-to-agent coordination: agents publish an Agent Card describing their skills, then negotiate and delegate tasks to one another.
- [ACP](/protocols/interop/acp) — A REST-native alternative to A2A for teams that want inter-agent messaging over plain HTTP with minimal new machinery.
- [AGNTCY](/protocols/interop/agntcy) — A Linux Foundation project building open infrastructure for an 'Internet of Agents' — discovery (OASF), identity, messaging (SLIM) and observability — so agents from different vendors interoperate.
- [SLIM](/protocols/interop/slim) — AGNTCY's secure, low-latency messaging substrate for agent-to-agent, human-in-the-loop and tool communication, designed for multi-modal exchange and quantum-safe security.
- [ANP](/protocols/interop/anp) — An open protocol aiming to be the 'HTTP of the agent internet': decentralized DID-based identity, a meta-protocol negotiation layer, and JSON-LD agent descriptions so billions of agents can connect.