---
type: Agentic Web Standard
title: "Agent2Agent Protocol (A2A)"
description: "How do two independent agents, built on different frameworks, discover each other and delegate a task to completion?"
resource: "https://a2a-protocol.org/latest/specification/"
tags: ["coordinate", "endpoint", "linux-foundation", "agent-to-agent-messaging", "describe-agent-capabilities", "discover-my-api"]
status: stable
generated: { by: agenticweb-builder/1.0, at: 2026-10-30T00:00:00Z }
verified: { by: process:agenticweb-engine, at: 2026-10-28T00:00:00Z }
stale_after: 2026-11-27T00:00:00Z
sources:
  - id: ref-1
    resource: "https://a2a-protocol.org/latest/specification/"
    title: "A2A Project, Overview - A2A Protocol (Agent2Agent (A2A) Protocol Specification, the page labels it \"Latest Released Version 1.0.0\"), checked 2026-10-28: \"Latest Released Version 1.0.0 Previous Versions 0.3.0 0.2.6 0.1.0\" \"Simple: Reuse existing, well-understood standards (HTTP, JSON-RPC 2.0, Server-Sent Events).\" \"Well-Known URI: Accessing https://{server_domain}/.well-known/agent-card.json\" \"A2A Servers MUST make an Agent Card available.\" \"The JSON-RPC protocol binding provides a simple, HTTP-based interface using JSON-RPC 2.0 for method calls and Server-Sent Events for streaming.\" \"The core ones officially supported are JSONRPC, GRPC and HTTP+JSON.\" \"Push Notifications: Asynchronous task updates delivered via server-initiated HTTP POST requests to a client-provided webhook URL, for long-running or disconnected scenarios.\" \"A2A and MCP are complementary protocols designed for different aspects of agentic systems:\" \"Think of MCP as the \"how-to\" for an agent to use a specific capability or access a resource.\" \"URI suffix: agent-card.json Change controller: A2A Protocol Working Group\""
    last_modified: 2026-10-28T00:00:00Z
  - id: ref-2
    resource: "https://github.com/a2aproject/A2A/releases/tag/v1.0.1"
    title: "a2aproject, Release v1.0.1 · a2aproject/A2A · GitHub (published 2026-05-28), checked 2026-10-28: \"1.0.1 (2026-05-26) Bug Fixes spec: prefer application/a2a+json in HTTP binding\""
    last_modified: 2026-05-28T00:00:00Z
  - id: ref-3
    resource: "https://github.com/a2aproject/A2A/blob/main/CHANGELOG.md"
    title: "a2aproject, A2A CHANGELOG.md (entries 1.0.1 dated 2026-05-26, 1.0.0 dated 2026-03-12, 0.3.0 dated 2025-07-30), checked 2026-10-28 (text checked at the raw.githubusercontent.com copy): \"* Change Well-Known URI for Agent Card hosting from agent.json to agent-card.json\""
    last_modified: 2026-05-26T00:00:00Z
  - id: ref-4
    resource: "https://github.com/a2aproject/A2A/pull/841"
    title: "holtskinner (GitHub), refactor!: Change Well-Known URI for Agent Card hosting from agent.json to agent-card.json by holtskinner · Pull Request #841 · a2aproject/A2A · GitHub (opened 2025-07-07, merged 2025-07-29), checked 2026-10-28"
    last_modified: 2025-07-29T00:00:00Z
  - id: ref-5
    resource: "https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/"
    title: "Google, Announcing the Agent2Agent Protocol (A2A) - Google Developers Blog, 2025-04-09: \"Today, we're launching a new, open protocol called Agent2Agent (A2A), with support and contributions from more than 50 technology partners\" \"A2A is an open protocol that complements Anthropic's Model Context Protocol (MCP), which provides helpful tools and context to agents.\""
    last_modified: 2025-04-09T00:00:00Z
  - id: ref-6
    resource: "https://www.linuxfoundation.org/press/linux-foundation-launches-the-agent2agent-protocol-project-to-enable-secure-intelligent-communication-between-ai-agents"
    title: "Linux Foundation, Linux Foundation Launches the Agent2Agent Protocol Project to Enable Secure, Intelligent Communication Between AI Agents (press release), 2025-06-23: \"The Linux Foundation, the nonprofit organization enabling mass innovation through open source, today announced the launch of the Agent2Agent (A2A) project, an open protocol created by Google for secure agent-to-agent communication and collaboration.\""
    last_modified: 2025-06-23T00:00:00Z
  - id: ref-7
    resource: "https://developers.googleblog.com/en/google-cloud-donates-a2a-to-linux-foundation/"
    title: "Rao Surapaneni, Todd Segal and Michael Vakoc, Google Cloud donates A2A to Linux Foundation - Google Developers Blog, 2025-06-23: \"The project will be hosted by the Linux Foundation and will be seeded with Google's transfer of the groundbreaking Agent2Agent (A2A) protocol specification, accompanying SDKs, and developer tooling.\""
    last_modified: 2025-06-23T00:00:00Z
  - id: ref-8
    resource: "https://github.com/a2aproject/A2A/blob/main/GOVERNANCE.md"
    title: "a2aproject, A2A GOVERNANCE.md, checked 2026-10-28 (text checked at the raw.githubusercontent.com copy): \"The Agent2Agent project is governed by the Technical Steering Committee. The Committee has nine seats, each held by the following companies:\""
    last_modified: 2026-10-28T00:00:00Z
  - id: ref-9
    resource: "https://aaif.io/blog/a2a-joins-aaif"
    title: "Agentic AI Foundation, A2A joins AAIF's open agentic stack - Agentic AI Foundation (AAIF), 2026-08-17: \"Agent2Agent (A2A), the open standard for inter-agent communication, is joining the Agentic AI Foundation (AAIF) as a hosted project.\" \"A2A v1.0, the first stable specification, shipped in March 2026.\""
    last_modified: 2026-08-17T00:00:00Z
  - id: ref-10
    resource: "https://github.com/aaif/project-proposals/issues/37"
    title: "AAIF, [Project Proposal] Agent2Agent Protocol (A2A) · Issue #37 · aaif/project-proposals · GitHub (comments of 2026-07-15 and 2026-08-04), checked 2026-10-28: \"The AAIF TC has approved A2A as a Growth Stage project, and it will now be passed to the Governing Board for a final vote.\" \"The GB has approved A2A as a Growth Stage project for inclusion into the AAIF.\""
    last_modified: 2026-08-04T00:00:00Z
  - id: ref-11
    resource: "https://a2a-protocol.org/latest/blog/2026/08/27/a-new-chapter-for-a2a-joining-the-agentic-ai-foundation/"
    title: "A2A Project, A New Chapter for A2A: Joining the Agentic AI Foundation - A2A Protocol, 2026-08-27: \"The Agent2Agent (A2A) protocol has officially been accepted as a Growth Stage project at the Agentic AI Foundation (AAIF).\" \"While the Model Context Protocol (MCP) serves as the vertical integration layer connecting agents to internal tools and databases, A2A acts as the horizontal protocol enabling peer-to-peer collaboration.\" \"By operating under the Linux Foundation-directed AAIF alongside sibling projects like MCP, goose, and AGENTS.md, A2A is protected from single-vendor constraints.\""
    last_modified: 2026-08-27T00:00:00Z
  - id: ref-12
    resource: "https://www.iana.org/assignments/well-known-uris"
    title: "IANA, Well-Known URIs (registry entry agent-card.json), checked 2026-10-28: \"agent-card.json https://a2a-protocol.org/latest/specification/ permanent Linux Foundation 2025-08-01\""
    last_modified: 2025-08-01T00:00:00Z
  - id: ref-13
    resource: "https://a2a-protocol.org/latest/whats-new-v1/"
    title: "A2A Project, What's New in v1.0 - A2A Protocol, checked 2026-10-28: \"Protocols are complementary, not competing\" \"preferredTransport and additionalInterfaces consolidated into supportedInterfaces[]\""
    last_modified: 2026-10-28T00:00:00Z
  - id: ref-14
    resource: "https://agenticresourcediscovery.org/spec/"
    title: "ards-project, ARD Specification - AgenticResourceDiscovery.org (v0.91), checked 2026-10-28: \"application/a2a-agent-card+json — A2A Agent Card\" \"The specification does not define or constrain the internal schema of specific agent types (MCP, A2A, etc.).\""
    last_modified: 2026-10-28T00:00:00Z
  - id: ref-15
    resource: "https://docs.cloud.google.com/gemini/enterprise/docs/release-notes"
    title: "Google Cloud, Gemini Enterprise release notes | Google Cloud Documentation (entry of 2026-08-17), checked 2026-10-28: \"Gemini Enterprise administrators can register and manage agents using Agent to UI (A2UI) to build custom interfaces and the Agent2Agent (A2A) Protocol for communication with Gemini Enterprise. With this release: The feature is generally available (GA) instead of Public Preview.\""
    last_modified: 2026-08-17T00:00:00Z
  - id: ref-16
    resource: "https://learn.microsoft.com/en-us/azure/foundry/agents/how-to/tools/agent-to-agent"
    title: "Microsoft, Connect to an A2A agent endpoint from Foundry Agent Service - Microsoft Foundry | Microsoft Learn (page date 2026-10-04), checked 2026-10-28: \"This article shows you how to configure an A2A connection and call a remote A2A endpoint from your Foundry Agent Service agent.\" \"Use the generally available a2a tool type for new integrations.\""
    last_modified: 2026-10-04T00:00:00Z
  - id: ref-17
    resource: "https://learn.microsoft.com/en-us/microsoft-copilot-studio/add-agent-agent-to-agent"
    title: "Microsoft, Connect to an agent over the Agent2Agent (A2A) protocol - Microsoft Copilot Studio | Microsoft Learn (page date 2026-08-26), checked 2026-10-28: \"By using A2A, Copilot Studio can delegate tasks to another agent, not just call APIs.\""
    last_modified: 2026-08-26T00:00:00Z
  - id: ref-18
    resource: "https://aws.amazon.com/blogs/machine-learning/introducing-agent-to-agent-protocol-support-in-amazon-bedrock-agentcore-runtime/"
    title: "AWS, Introducing agent-to-agent protocol support in Amazon Bedrock AgentCore Runtime | Artificial Intelligence (AWS Machine Learning Blog), 2025-11-11: \"We recently announced the support for Agent-to-Agent (A2A) protocol on Amazon Bedrock AgentCore Runtime.\""
    last_modified: 2025-11-11T00:00:00Z
  - id: ref-19
    resource: "https://architecture.learning.sap.com/docs/ref-arch/ae6821"
    title: "SAP, Integrating AI Agents with Joule (Outbound A2A) | SAP Architecture Center (last updated 2026-10-26), checked 2026-10-28: \"At runtime, when a user's request triggers this scenario, Joule acts as an A2A client.\""
    last_modified: 2026-10-26T00:00:00Z
  - id: ref-20
    resource: "https://architecture.learning.sap.com/news/2026/10/27/a2a-agent-gateway-interoperability"
    title: "SAP, Third-party agents can now interoperate with SAP Agents via the Agent Gateway | SAP Architecture Center, 2026-10-27: \"SAP announces the October 2026 general availability of inbound Agent2Agent (A2A) interoperability, connecting SAP's autonomous enterprise agents with the broader AI ecosystem through open standards and governed access.\""
    last_modified: 2026-10-27T00:00:00Z
  - id: ref-21
    resource: "https://www.salesforce.com/news/press-releases/2025/06/23/agentforce-3-announcement/?bc=OTH"
    title: "Salesforce, Salesforce Announces Agentforce 3 - Salesforce (press release), 2025-06-23: \"MuleSoft MCP and A2A support — generally available in July\""
    last_modified: 2025-06-23T00:00:00Z
  - id: ref-22
    resource: "https://www.theregister.com/devops/2026/08/07/ai-titans-to-tidy-agent-frontier-with-plugin-prescription/5285017"
    title: "Joab Jackson, The Register, AI titans to tidy agent frontier with plugin prescription, 2026-08-07: \"Google folded its own Agent2Agent (A2A) agentic communications protocol effort into AAIF.\""
    last_modified: 2026-08-07T00:00:00Z
  - id: ref-23
    resource: "https://www.infoworld.com/article/4088217/what-is-a2a-how-the-agent-to-agent-protocol-enables-autonomous-collaboration.html"
    title: "Josh Fruhlinger, InfoWorld, What is A2A? How the agent-to-agent protocol enables autonomous collaboration | InfoWorld, 2025-11-18: \"A2A, short for agent-to-agent, is an open, vendor-neutral protocol that allows autonomous AI agents to communicate, coordinate, and delegate work to one another.\""
    last_modified: 2025-11-18T00:00:00Z
  - id: ref-24
    resource: "https://www.infoworld.com/article/4239696/stop-building-agents-that-cant-change-models.html"
    title: "Alex Merced, InfoWorld, Stop building agents that can't change models | InfoWorld, 2026-10-26 (first published 2026-10-23): \"The Agent2Agent (A2A) protocol, which reached version 1.0 in March 2026 and joined the AAIF in August, lets agents from different vendors hand off work.\""
    last_modified: 2026-10-26T00:00:00Z
---

# Agent2Agent Protocol (A2A)

Agent2Agent Protocol (A2A) is an agentic-web standard (endpoint — /.well-known/agent-card.json) at step 6, Coordinate, governed by Linux Foundation: launched as the Agent2Agent project on 2025-06-23, seeded with Google's transfer of the specification, SDKs and tooling; its status is "Stable: v1.0 is the first stable specification". It answers: "How do two independent agents, built on different frameworks, discover each other and delegate a task to completion?" Implementation status is multi-implementation (150+ supporting organizations, claimed by the Linux Foundation on 9 April 2026), last verified 2026-10-28.

# Overview

A2A is an open protocol that lets AI agents built by different vendors and on different frameworks find each other, delegate tasks and exchange results, without having to share their internal thoughts, plans or tool implementations [^ref-1][^ref-5]. An A2A server describes itself in a JSON Agent Card, usually published at /.well-known/agent-card.json, which lists its skills, endpoints and security requirements; a client then talks to it over JSON-RPC 2.0, gRPC or HTTP+JSON, with streaming and push notifications for long-running tasks [^ref-1]. Google announced A2A in April 2025 and donated it to the Linux Foundation in June 2025, and in August 2026 it joined the Agentic AI Foundation, where MCP is also hosted [^ref-5][^ref-6][^ref-7][^ref-9][^ref-11]. The project describes A2A and MCP as complementary: MCP is how an agent uses tools and data, A2A is how agents work with each other, and one agent can use both [^ref-1][^ref-13].

# Examples

```http
GET {origin}/.well-known/agent-card.json
# parse: Accept either card shape and record which one was seen. A v1.0 card places url, protocolBinding, and protocolVersion inside supportedInterfaces[] (preferredTransport and additionalInterfaces fold into that array). A legacy v0.3 card carries a top-level url. name may be present on either shape.
# on absent: 404 or non-JSON response means no public Agent Card is hosted at this well-known path; the origin may still run A2A behind auth or a registry
```

# Knowledge Graph

* **Lifecycle Step**: [6 Coordinate](/category/coordinate/index.md)
* **Depended on by**: [Ad Context Protocol (AdCP)](/okf/protocols/adcp.md)
* **Pairs with**: [Model Context Protocol](/okf/protocols/mcp.md), [x402](/okf/protocols/x402.md), [Agent Payments Protocol (AP2)](/okf/protocols/ap2.md), [Official MCP Registry](/okf/protocols/mcp-registry.md), [The Agent Identity Document: A Hosted, Accountable Public Record for AI Agents](/okf/protocols/agent-identity-document.md), [Agent Client Protocol](/okf/protocols/agent-client-protocol.md)
* **Related terms**: [Agent Card](/okf/terms/agent-card.md), [Well-known URI](/okf/terms/well-known.md), [Agentic web](/okf/terms/agentic-web.md), [Subagent](/okf/terms/subagent.md), [Agent2Agent (A2A)](/okf/terms/agent-to-agent.md), [A2A Task](/okf/terms/a2a-task.md), [AI agent](/okf/terms/ai-agent.md)
* **Compared in**: [Webhooks & RPC vs Agent2Agent Protocol (A2A) (classic vs agentic)](/compare/webhooks-vs-a2a/index.md), [Agent2Agent Protocol (A2A) vs Model Context Protocol](/compare/a2a-vs-mcp/index.md), [Agent2Agent Protocol (A2A) vs MCP Server Cards](/compare/a2a-vs-mcp-server-cards/index.md), [Agent2Agent Protocol (A2A) vs Agent Communication Protocol](/compare/a2a-vs-agent-communication-protocol/index.md), [Agent Identity & Discovery (AID) vs Agent2Agent Protocol (A2A)](/compare/aid-vs-a2a/index.md), [Agent2Agent Protocol (A2A) vs Agent Network Protocol](/compare/a2a-vs-anp/index.md), [Agent2Agent Protocol (A2A) vs Coral Protocol (CoralOS)](/compare/a2a-vs-coral-protocol/index.md), [Agent2Agent Protocol (A2A) vs Agent Interaction & Transaction Protocol (AITP)](/compare/a2a-vs-aitp/index.md), [Agent2Agent Protocol (A2A) vs Secure Low-Latency Interactive Messaging (SLIM)](/compare/a2a-vs-slim/index.md), [Agent2Agent Protocol (A2A) vs Natural Language Interaction Protocol (NLIP)](/compare/a2a-vs-nlip/index.md)

[^ref-1]: A2A Project, Overview - A2A Protocol (Agent2Agent (A2A) Protocol Specification, the page labels it "Latest Released Version 1.0.0"), checked 2026-10-28: "Latest Released Version 1.0.0 Previous Versions 0.3.0 0.2.6 0.1.0" "Simple: Reuse existing, well-understood standards (HTTP, JSON-RPC 2.0, Server-Sent Events)." "Well-Known URI: Accessing https://{server_domain}/.well-known/agent-card.json" "A2A Servers MUST make an Agent Card available." "The JSON-RPC protocol binding provides a simple, HTTP-based interface using JSON-RPC 2.0 for method calls and Server-Sent Events for streaming." "The core ones officially supported are JSONRPC, GRPC and HTTP+JSON." "Push Notifications: Asynchronous task updates delivered via server-initiated HTTP POST requests to a client-provided webhook URL, for long-running or disconnected scenarios." "A2A and MCP are complementary protocols designed for different aspects of agentic systems:" "Think of MCP as the "how-to" for an agent to use a specific capability or access a resource." "URI suffix: agent-card.json Change controller: A2A Protocol Working Group" (https://a2a-protocol.org/latest/specification/)
[^ref-2]: a2aproject, Release v1.0.1 · a2aproject/A2A · GitHub (published 2026-05-28), checked 2026-10-28: "1.0.1 (2026-05-26) Bug Fixes spec: prefer application/a2a+json in HTTP binding" (https://github.com/a2aproject/A2A/releases/tag/v1.0.1)
[^ref-3]: a2aproject, A2A CHANGELOG.md (entries 1.0.1 dated 2026-05-26, 1.0.0 dated 2026-03-12, 0.3.0 dated 2025-07-30), checked 2026-10-28 (text checked at the raw.githubusercontent.com copy): "* Change Well-Known URI for Agent Card hosting from agent.json to agent-card.json" (https://github.com/a2aproject/A2A/blob/main/CHANGELOG.md)
[^ref-4]: holtskinner (GitHub), refactor!: Change Well-Known URI for Agent Card hosting from agent.json to agent-card.json by holtskinner · Pull Request #841 · a2aproject/A2A · GitHub (opened 2025-07-07, merged 2025-07-29), checked 2026-10-28 (https://github.com/a2aproject/A2A/pull/841)
[^ref-5]: Google, Announcing the Agent2Agent Protocol (A2A) - Google Developers Blog, 2025-04-09: "Today, we're launching a new, open protocol called Agent2Agent (A2A), with support and contributions from more than 50 technology partners" "A2A is an open protocol that complements Anthropic's Model Context Protocol (MCP), which provides helpful tools and context to agents." (https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/)
[^ref-6]: Linux Foundation, Linux Foundation Launches the Agent2Agent Protocol Project to Enable Secure, Intelligent Communication Between AI Agents (press release), 2025-06-23: "The Linux Foundation, the nonprofit organization enabling mass innovation through open source, today announced the launch of the Agent2Agent (A2A) project, an open protocol created by Google for secure agent-to-agent communication and collaboration." (https://www.linuxfoundation.org/press/linux-foundation-launches-the-agent2agent-protocol-project-to-enable-secure-intelligent-communication-between-ai-agents)
[^ref-7]: Rao Surapaneni, Todd Segal and Michael Vakoc, Google Cloud donates A2A to Linux Foundation - Google Developers Blog, 2025-06-23: "The project will be hosted by the Linux Foundation and will be seeded with Google's transfer of the groundbreaking Agent2Agent (A2A) protocol specification, accompanying SDKs, and developer tooling." (https://developers.googleblog.com/en/google-cloud-donates-a2a-to-linux-foundation/)
[^ref-8]: a2aproject, A2A GOVERNANCE.md, checked 2026-10-28 (text checked at the raw.githubusercontent.com copy): "The Agent2Agent project is governed by the Technical Steering Committee. The Committee has nine seats, each held by the following companies:" (https://github.com/a2aproject/A2A/blob/main/GOVERNANCE.md)
[^ref-9]: Agentic AI Foundation, A2A joins AAIF's open agentic stack - Agentic AI Foundation (AAIF), 2026-08-17: "Agent2Agent (A2A), the open standard for inter-agent communication, is joining the Agentic AI Foundation (AAIF) as a hosted project." "A2A v1.0, the first stable specification, shipped in March 2026." (https://aaif.io/blog/a2a-joins-aaif)
[^ref-10]: AAIF, [Project Proposal] Agent2Agent Protocol (A2A) · Issue #37 · aaif/project-proposals · GitHub (comments of 2026-07-15 and 2026-08-04), checked 2026-10-28: "The AAIF TC has approved A2A as a Growth Stage project, and it will now be passed to the Governing Board for a final vote." "The GB has approved A2A as a Growth Stage project for inclusion into the AAIF." (https://github.com/aaif/project-proposals/issues/37)
[^ref-11]: A2A Project, A New Chapter for A2A: Joining the Agentic AI Foundation - A2A Protocol, 2026-08-27: "The Agent2Agent (A2A) protocol has officially been accepted as a Growth Stage project at the Agentic AI Foundation (AAIF)." "While the Model Context Protocol (MCP) serves as the vertical integration layer connecting agents to internal tools and databases, A2A acts as the horizontal protocol enabling peer-to-peer collaboration." "By operating under the Linux Foundation-directed AAIF alongside sibling projects like MCP, goose, and AGENTS.md, A2A is protected from single-vendor constraints." (https://a2a-protocol.org/latest/blog/2026/08/27/a-new-chapter-for-a2a-joining-the-agentic-ai-foundation/)
[^ref-12]: IANA, Well-Known URIs (registry entry agent-card.json), checked 2026-10-28: "agent-card.json https://a2a-protocol.org/latest/specification/ permanent Linux Foundation 2025-08-01" (https://www.iana.org/assignments/well-known-uris)
[^ref-13]: A2A Project, What's New in v1.0 - A2A Protocol, checked 2026-10-28: "Protocols are complementary, not competing" "preferredTransport and additionalInterfaces consolidated into supportedInterfaces[]" (https://a2a-protocol.org/latest/whats-new-v1/)
[^ref-14]: ards-project, ARD Specification - AgenticResourceDiscovery.org (v0.91), checked 2026-10-28: "application/a2a-agent-card+json — A2A Agent Card" "The specification does not define or constrain the internal schema of specific agent types (MCP, A2A, etc.)." (https://agenticresourcediscovery.org/spec/)
[^ref-15]: Google Cloud, Gemini Enterprise release notes | Google Cloud Documentation (entry of 2026-08-17), checked 2026-10-28: "Gemini Enterprise administrators can register and manage agents using Agent to UI (A2UI) to build custom interfaces and the Agent2Agent (A2A) Protocol for communication with Gemini Enterprise. With this release: The feature is generally available (GA) instead of Public Preview." (https://docs.cloud.google.com/gemini/enterprise/docs/release-notes)
[^ref-16]: Microsoft, Connect to an A2A agent endpoint from Foundry Agent Service - Microsoft Foundry | Microsoft Learn (page date 2026-10-04), checked 2026-10-28: "This article shows you how to configure an A2A connection and call a remote A2A endpoint from your Foundry Agent Service agent." "Use the generally available a2a tool type for new integrations." (https://learn.microsoft.com/en-us/azure/foundry/agents/how-to/tools/agent-to-agent)
[^ref-17]: Microsoft, Connect to an agent over the Agent2Agent (A2A) protocol - Microsoft Copilot Studio | Microsoft Learn (page date 2026-08-26), checked 2026-10-28: "By using A2A, Copilot Studio can delegate tasks to another agent, not just call APIs." (https://learn.microsoft.com/en-us/microsoft-copilot-studio/add-agent-agent-to-agent)
[^ref-18]: AWS, Introducing agent-to-agent protocol support in Amazon Bedrock AgentCore Runtime | Artificial Intelligence (AWS Machine Learning Blog), 2025-11-11: "We recently announced the support for Agent-to-Agent (A2A) protocol on Amazon Bedrock AgentCore Runtime." (https://aws.amazon.com/blogs/machine-learning/introducing-agent-to-agent-protocol-support-in-amazon-bedrock-agentcore-runtime/)
[^ref-19]: SAP, Integrating AI Agents with Joule (Outbound A2A) | SAP Architecture Center (last updated 2026-10-26), checked 2026-10-28: "At runtime, when a user's request triggers this scenario, Joule acts as an A2A client." (https://architecture.learning.sap.com/docs/ref-arch/ae6821)
[^ref-20]: SAP, Third-party agents can now interoperate with SAP Agents via the Agent Gateway | SAP Architecture Center, 2026-10-27: "SAP announces the October 2026 general availability of inbound Agent2Agent (A2A) interoperability, connecting SAP's autonomous enterprise agents with the broader AI ecosystem through open standards and governed access." (https://architecture.learning.sap.com/news/2026/10/27/a2a-agent-gateway-interoperability)
[^ref-21]: Salesforce, Salesforce Announces Agentforce 3 - Salesforce (press release), 2025-06-23: "MuleSoft MCP and A2A support — generally available in July" (https://www.salesforce.com/news/press-releases/2025/06/23/agentforce-3-announcement/?bc=OTH)
[^ref-22]: Joab Jackson, The Register, AI titans to tidy agent frontier with plugin prescription, 2026-08-07: "Google folded its own Agent2Agent (A2A) agentic communications protocol effort into AAIF." (https://www.theregister.com/devops/2026/08/07/ai-titans-to-tidy-agent-frontier-with-plugin-prescription/5285017)
[^ref-23]: Josh Fruhlinger, InfoWorld, What is A2A? How the agent-to-agent protocol enables autonomous collaboration | InfoWorld, 2025-11-18: "A2A, short for agent-to-agent, is an open, vendor-neutral protocol that allows autonomous AI agents to communicate, coordinate, and delegate work to one another." (https://www.infoworld.com/article/4088217/what-is-a2a-how-the-agent-to-agent-protocol-enables-autonomous-collaboration.html)
[^ref-24]: Alex Merced, InfoWorld, Stop building agents that can't change models | InfoWorld, 2026-10-26 (first published 2026-10-23): "The Agent2Agent (A2A) protocol, which reached version 1.0 in March 2026 and joined the AAIF in August, lets agents from different vendors hand off work." (https://www.infoworld.com/article/4239696/stop-building-agents-that-cant-change-models.html)