mq9
A message broker built specifically for multi-agent systems that unifies agent registration, capability-based discovery, and reliable asynchronous messaging, with native support for the A2A agent-to-agent protocol.
mq9 is infrastructure for multi-agent systems that solves two problems general-purpose tools do not address well together: how agents find each other and how they communicate reliably when tasks are long-running, agents come and go, and communication is not simple request-response. It provides an AgentCard data model, capability-based semantic discovery, persistent per-agent mailboxes, many-to-many agent topology, and long-task state retention, unified in one broker with shared storage, networking, and cluster coordination.
It natively supports the A2A protocol through a Python SDK facade over the official a2a-sdk, letting a developer build a compliant A2A agent in a small amount of code. The broker itself is a separate protocol inside the RobustMQ project, while this repository holds SDKs for Python, Java, Go, Rust, and JavaScript, a LangChain toolkit, demos, and the project's documentation site.