ThirdBrAIn.tech

Advanced Video Search

Agent2Agent (A2A) protocol

3 min read

Agent2Agent (A2A) protocol

Open protocol that lets agents built by different vendors and frameworks discover each other, delegate tasks and exchange results. Complements model-context-protocol (agent-to-tool) rather than competing with it.

Traction, as of 2026-10-10

A2A has moved from a Google proposal to a hosted project of the Agentic AI Foundation, with cloud platforms integrating it and a stable 1.0 spec. Adoption figures below are the project’s and the Linux Foundation’s own; no independent measurement was found.

Timeline

  • 2025-04: announced by Google as an open standard.
  • 2025-06-23: donated to the Linux Foundation (Open Source Summit NA, Denver); founding members AWS, Cisco, Microsoft, Salesforce, SAP, ServiceNow (Google Developers blog).
  • 2026-03-12: v1.0.0 released, confirmed on the GitHub release. It includes breaking changes from 0.3.
  • 2026-04-09: Linux Foundation one-year release: “more than 150 organizations”, up from “more than 50” in April 2025. Integrations named for Microsoft (Azure AI Foundry, Copilot Studio) and AWS (Amazon Bedrock AgentCore Runtime). The release does not say whether these are GA or preview.
  • 2026-05-26: v1.0.1 (tagged 2026-05-28): HTTP binding and spec fixes, no new features.
  • 2026-08-17: AAIF post: A2A “is joining the Agentic AI Foundation as a hosted project” (AAIF). The post names no membership tier and no effective date beyond the post date.

Concepts

  • Agent Card: JSON metadata describing an agent’s skills, endpoints and auth. Signed cards (JWS with JSON canonicalisation) are reported as a v1.0 addition by secondary sources; not checked against the spec.
  • Task / Message / Part / Artifact: the unit of delegated work and its content. Secondary sources say v1.0 unified the Text/File/Data parts into a single Part.
  • Bindings: JSON-RPC 2.0 over HTTPS, gRPC and HTTP+JSON/REST (per secondary sources); version negotiation via supportedInterfaces.
  • v1.0 also added multi-tenancy, cursor-based task pagination and the OAuth Device Code flow (secondary sources). The v1.0.0 release notes confirm breaking changes such as “Combine TaskPushNotificationConfig and PushNotificationConfig”, the ProtoJSON enum format and the removal of a redundant final field.

Adoption

  • Cloud platforms: Azure AI Foundry and Copilot Studio; Amazon Bedrock AgentCore Runtime (Linux Foundation release, 2026-04-09).
  • Frameworks: google-adk, microsoft-agent-framework (A2A 1.0), LangGraph, crewai and AG2, per Google and Microsoft posts (not re-checked today).
  • Production: the Linux Foundation says there are “active production deployments across multiple industries”, naming supply chain, financial services, insurance and IT operations. It names no individual enterprise. The AAIF post names Huawei, Tencent, Google Cloud, Microsoft Azure, AWS and PayPal as deployers, not as backers.
  • Stars: about 26,100 on the GitHub repository (2026-10-10); repository created 2025-03-25, Apache-2.0, last push 2026-10-08.

Intended to sit next to MCP and ag-ui; commerce protocols build on it (agent-payments-protocols).

Open items

  • The AAIF hosting date: the AAIF post is dated 2026-08-17, but one search summary says Google Cloud donated A2A to AAIF on 2026-08-20. That second source is unverified, so the note uses 2026-08-17.
  • Whether the 2026 Linux Foundation release’s cloud integrations are GA or preview is not stated.
  • The 2025 version history (0.1 to 0.3) dates are unverified.
  • Adoption is self-reported by the project and its backers. Independent measurement is not available. A skeptical 2026 analysis argues A2A matters mainly where agents are independent systems with their own trust boundaries.

Sources

Filter Videos

Tags

Advanced Tag Filters

Channels

Favorites

Active list: Quick Saves

This list is empty

Browse videos and save them to a list to get started

Recent Updates

See 1493 more →

Backlinks