The agent protocol stack settles into two standards
A2A crossed 150 organizations in its first year. With MCP for tools and A2A for agents, the wiring of the agent economy has a shape.
- The Agent2Agent (A2A) protocol reached v1.0 and grew from about 50 to more than 150 backing organizations in its first year.
- Backers include AWS, Cisco, Google, IBM, Microsoft, Salesforce, SAP, and ServiceNow. The core repository passed 22,000 GitHub stars, with SDKs in five languages.
- A2A and the Model Context Protocol (MCP) are now both Linux Foundation projects. MCP connects agents to tools. A2A connects agents to each other.
- The interoperability layer of the agent economy is consolidating around two complementary standards, not one platform.
The plumbing of the agent economy is settling, and it is settling into two standards rather than one. The Agent2Agent protocol, known as A2A, hit its v1.0 release and marked its first year with more than 150 backing organizations, up from around 50 twelve months earlier. The Linux Foundation laid out the milestone alongside integrations across the major clouds.
What A2A is, and what shipped
A2A is a standard for how one agent talks to another across systems and company lines. The v1.0 release added multi-protocol support, enterprise multi-tenancy, updated security flows, and a migration path for early adopters. The backer list reads like a roll call of enterprise software: AWS, Cisco, Google, IBM, Microsoft, Salesforce, SAP, and ServiceNow. The core repository has passed 22,000 stars on GitHub, and the SDK now ships in five languages.
MCP and A2A, split by job
The two standards do not compete. They divide the work. MCP, which we cover in our agent protocol glossary entry, connects an agent to tools and data, where the tool is a passive capability the agent calls. A2A connects an agent to another agent, where the peer has its own reasoning and can be handed part of the goal. One is about reaching for a tool. The other is about delegating to a colleague. When several agents coordinate on a single job, you get a multi-agent system, and A2A is the language they speak.
Why a two-standard stack matters
For most of the last year, buyers worried the agent space would fracture into rival, incompatible platforms. Two open standards under the same foundation is the opposite outcome. It means an agent built on one vendor's stack can call tools and delegate to agents on another, without a single company owning the wiring. That is the difference between a market and a walled garden. For the wider vocabulary showing up in these announcements, our terminology guide keeps score.
Sources: Linux Foundation press release, AIwire, analysis of MCP vs A2A.