Agent2Agent Protocol

license

Apache-2.0(OSI)

source

public(spec + reference SDKs in 6 languages)

core features withheld

no — the Linux Foundation project sells nothing - one Apache-2.0 LICENSE at the root, no ee/ or enterprise/ path, and all six reference SDKs published as public a2aproject repos on public package registries

The specification is published under Apache-2.0, and its reference SDKs are public repositories in the same a2aproject organization. The repository has no enterprise or commercial directory and no second license file at its root, and there is no paid tier or vendor product beside the protocol, so nothing is withheld from what is published.

• https://api.github.com/repos/a2aproject/A2A recorded 2026-08-12

  Repo metadata: license spdx_id Apache-2.0, default branch main, 25,300 stars, not archived.

• https://api.github.com/repos/a2aproject/A2A/contents recorded 2026-08-12

  Root tree. LICENSE, CODE_OF_CONDUCT.md, CONTRIBUTING.md, GOVERNANCE.md, MAINTAINERS.md, SECURITY.md, adrs, docs, scripts, specification. No ee/, enterprise/, commercial/ or proprietary/ path, and no second LICENSE anywhere at the root.

• https://github.com/a2aproject/A2A recorded 2026-06-04

  Apache-2.0 license, LF-hosted open protocol, spec v1.0.1 + 6-language SDKs, ~24k stars

• https://raw.githubusercontent.com/a2aproject/A2A/main/LICENSE recorded 2026-09-28

  The raw LICENSE file is the unmodified Apache License text, headed "Apache License" and "Version 2.0, January 2004", with no added field-of-use or commercial restriction.

• https://raw.githubusercontent.com/a2aproject/A2A/main/README.md recorded 2026-09-28

  The README closes: "The A2A Protocol is an open source project under the Linux Foundation, contributed by Google. It is licensed under the [Apache License 2.0](LICENSE)". Its SDK list links public a2aproject repositories installed with "pip install a2a-sdk", "npm install @a2a-js/sdk", "dotnet add package A2A" and "cargo add a2a-lf". Searched the body for pricing, paid, subscription, license key, premium and hosted: none.

Adoption is measured as combined downloads of the protocol's two most-installed reference SDKs, `a2a-sdk` on PyPI and `@a2a-js/sdk` on npm, the channels an A2A implementation installs. The protocol has no package of its own. The Linux Foundation's count of supporting organizations and the cloud integrations it names corroborate a broad footprint.

• https://api.npmjs.org/downloads/point/last-month/@a2a-js/sdk recorded 2026-10-03

  npm downloads point API: 12,267,118 downloads for `@a2a-js/sdk` over 2026-09-02 to 2026-10-01.

• https://pypistats.org/api/packages/a2a-sdk/recent recorded 2026-10-03

  "last_month":10333975 downloads for `a2a-sdk` (last_week 2,888,989, last_day 371,578).

• https://www.linuxfoundation.org/press/a2a-protocol-surpasses-150-organizations-lands-in-major-cloud-platforms-and-sees-enterprise-production-use-in-first-year recorded 2026-09-28

  Linux Foundation press release dated April 9, 2026: "Since April 2025, the number of supporting organizations has grown from more than 50 to over 150" and names "AWS, Cisco, Google, IBM, Microsoft, Salesforce, SAP, and ServiceNow", with "Microsoft integrated A2A into Azure AI Foundry and Copilot Studio" and "AWS added support through Amazon Bedrock AgentCore Runtime". It publishes no user, request or download count.

A2A is a specification, and neither the repository nor the specification publishes a benchmark, leaderboard or performance figure, so there is nothing to score for capability. How widely it is implemented is already reflected in adoption, and the Model Context Protocol is left unscored for the same reason.

• https://a2a-protocol.org/latest/specification/ recorded 2026-09-29

  The specification page defines protocol operations and wire behavior, for example task listing that "MUST use cursor-based pagination for performance and consistency". Searched the body for benchmark, leaderboard and throughput: none. The only other performance wording is descriptive, such as a "high-performance, strongly-typed interface" for the gRPC binding, and the page publishes no benchmark result or performance figure for the protocol.

• https://github.com/a2aproject/A2A recorded 2026-08-13

  Repo page - specification, ADRs, governance and reference SDK links. Described as an open protocol and spec, not a runtime. No benchmark result, leaderboard entry or performance figure published.

• https://github.com/a2aproject/A2A recorded 2026-08-14

  A specification repository - spec, ADRs, governance, maintainers and the reference SDK links - with no benchmark, leaderboard or performance figure anywhere on it.

• https://raw.githubusercontent.com/a2aproject/A2A/main/README.md recorded 2026-09-29

  The README describes A2A as "An open protocol enabling communication and interoperability between opaque agentic applications." and lists specification, documentation and SDK links. Searched the body for benchmark, leaderboard, latency, throughput and performance: none.