A2A Protocol Joins MCP Under Agentic AI Foundation After v1.0

From launch-day promise to shared infrastructure

Google introduced the Agent2Agent protocol, or A2A, in April 2025. It was an open specification meant to let AI agents talk to each other, share information securely and coordinate actions across enterprise applications, and more than 50 technology partners backed it at launch, including Atlassian, Salesforce, SAP, ServiceNow, PayPal and LangChain.21 Eighteen months later, the result is mostly settled. A2A has moved from a Google project to a standard governed by the Linux Foundation. It shipped a stable v1.0 release, and it now sits under the same foundation as Anthropic's Model Context Protocol (MCP).526

The adoption figures look strong. The Linux Foundation said in April 2026 that more than 150 organizations supported the protocol. It also said Google, Microsoft and AWS had built A2A deeply into their platforms and that companies in several industries were running it in production.1 The open question has changed from whether A2A will survive to how much real use those numbers represent.

What Google actually shipped

The first design was deliberately conservative. A2A was built on HTTP, server-sent events and JSON-RPC, so it could fit into the IT systems enterprises already run. Its authentication matched the schemes OpenAPI supports.21 Agents describe what they can do in a JSON "Agent Card," and other agents use those cards to find the right partner for a job. Work is organized around a "task" object with a defined lifecycle. Tasks can last anywhere from seconds to days when humans are involved, and the output of a task is called an "artifact."21

Google's main example was hiring. A manager asks one agent to find candidates, and that agent hands parts of the work to specialist agents for sourcing, interview scheduling and background checks.2124 The example was ordinary on purpose. It cast A2A as plumbing for routine business processes, not a research project.

From the start, Google said A2A complements MCP rather than competing with it.21 InfoQ's early coverage made the line clearer. Google's documentation says A2A lets agents talk to each other "as agents" instead of as tools, but it also suggests that applications represent A2A agents as MCP resources.28 So the two protocols were designed to overlap a little, even if the marketing made them sound separate.

The road to neutral governance

Governance changed in steps. Google gave A2A to the Linux Foundation at Open Source Summit North America in June 2025. AWS, Cisco, Microsoft, Salesforce, SAP and ServiceNow joined as founding members.525 Version 0.3 followed in July 2025. It added gRPC support, signed security cards and broader Python SDK support, and Google released native A2A support in its Agent Development Kit at the same time.22 In August 2025, IBM folded its competing Agent Communication Protocol into A2A instead of keeping a rival spec going.5

The change that matters most for enterprise buyers came in March 2026, when v1.0 arrived as the first stable, production-ready version.26 The release added Signed Agent Cards for cryptographic identity checks, multi-tenancy, updated security flows and a migration path for early adopters.2 Analysts at one firm noted that version negotiation and support for multiple transports, including gRPC and WebSocket, also came with v1.0.4 The SDKs grew from a single Python version to five production-ready languages, including JavaScript, Java, Go and .NET.2

The latest step came in August 2026, when A2A became a hosted project of the Agentic AI Foundation (AAIF). That is the Linux Foundation body that already hosts MCP, Block's goose and OpenAI's AGENTS.md.5 Axios reported, as cited in later coverage, that AAIF grew from fewer than 40 members at its December 2025 launch to more than 250 by August 2026.5

Where the reporting diverges

The coverage agrees on the overall story but disagrees on several details. Readers should not take any single date as final.

• When A2A joined AAIF. Several outlets give August 17, 2026.45 Enterprise DNA gives August 20.8
• When v1.0 shipped. Google's own open-source blog says March 2026, and one analysis puts the spec freeze on March 12.264 At least one enterprise consultancy dates v1.0 to April 9, 2026, which is the one-year anniversary.7 That most likely mixes up the release with the anniversary announcement.
• Later versions. One source says a v1.2 with signed Agent Cards came out in March 2026.29 Another says v1.2 arrived "reportedly" around Cloud Next 2026, and it lists signed cards as part of v1.0.52
• The donation date. One October 2026 commentary describes the Linux Foundation donation as an early-2026 event.6 That conflicts with Google's own account of a June 2025 handover.26

The primary sources are the most reliable guide here: Google's blogs and the Linux Foundation's press release. They point to a June 2025 donation, a March 2026 v1.0 and an August 2026 move into AAIF.2615

The MCP question, settled

The industry has mostly stopped asking whether to choose A2A or MCP. Vendors and analysts now describe the same picture. MCP is the vertical layer, connecting an agent to tools, databases and APIs. A2A is the horizontal layer, coordinating work between agents that may come from different vendors.1620 An IT-operations vendor puts it plainly: pulling logs or updating a ServiceNow ticket is an MCP job, while handing off triage or sequencing fixes across agents is an A2A job.14

The two protocols are not equally mature. MCP came first, in November 2024, and one analysis credits it with more than 10,000 servers and 97 million monthly downloads. A2A's main figures are organizational: 150-plus supporters and native support on all three major clouds.4 Some integration guides tell enterprises, especially smaller ones, to start with MCP and add A2A only once several agents need to coordinate across vendor or company boundaries.1918 Taken together, MCP is the default starting point, and A2A only becomes necessary once multiple agents are involved.

Bringing both under AAIF matters mainly because it lowers procurement risk. Enterprise DNA argues that moving from one agent framework to another should no longer mean rebuilding every integration.8 Other analysts describe the change as one of trust structure rather than technology.4

The enterprise case — and its caveats

The production story centers on the cloud platforms. Coverage lists Microsoft Azure AI Foundry, Amazon Bedrock AgentCore and Salesforce Agentforce as headline deployments, and names IBM, Cisco, SAP and ServiceNow among users.9 Partners have also extended the protocol. Twilio added latency signals so tasks get routed to the fastest agent, and Adobe uses A2A to connect its distributed agents with Google Cloud's ecosystem.22

A2A has also become a base for agentic commerce. In September 2025, Google Cloud and Coinbase released the Agent Payments Protocol (AP2) as a formal A2A extension.25 The Linux Foundation counts more than 60 payments and financial-services organizations backing it.2

The more skeptical coverage deserves weight, though. One adoption review points out that the Linux Foundation's anniversary report named industries but published no deployment count or usage numbers behind the 150-organization figure.5 The same review warns that WeChat, its biggest example, may use A2A's name for an access arrangement Tencent controls, not the full open spec.5 One critique's title says outright that real usage has not moved since the AAIF announcement.4 Another analyst argues that the meaningful test is whether companies keep A2A in production after their first real incident.3

There are technical gaps as well. A2A standardizes the message envelope but not the contents of skill payloads. Two agents that both advertise "search inventory" may expect completely different inputs.9 Security researchers warn that prompt injection through A2A can spread along delegation chains instead of staying inside one session.17 The governance shift may also be more cosmetic than it looks. As of August 2026, A2A's governance file still described an eight-seat technical committee drawn from the original corporate backers and did not mention AAIF.4

The verdict

A2A has done what Google promised in April 2025 and more. It has become a vendor-neutral standard, has stable releases and is built into every major cloud. It now shares a governance home with MCP, which effectively ends the industry's agent-protocol fight. But the adoption numbers mostly measure how many organizations have endorsed it, not how much they use it. For companies running autonomous AI agents, A2A is now safe to bet on. It does not yet prove that multi-agent systems are ready for production. The next year will show whether the 150 supporters become running deployments that someone can actually count.