Agent2Agent (A2A) Protocol
Agent2Agent (A2A) Protocol is a framework maintained by Agent2Agent project (Linux Foundation; Agentic AI Foundation project)14512. Its source code is public1 under the Apache License 2.02.
Agent2Agent (A2A) is an open protocol for communication between AI agents built on different frameworks and run by different parties. Agents publish Agent Cards describing their capabilities and endpoints, and exchange messages and long-running tasks over JSON-RPC, gRPC, or HTTP+JSON bindings without exposing internal state or tools. The project publishes the specification, SDKs, and samples.16
- Documentation: Website and documentation (external site: a2a-protocol.org)
- Documentation: Specification (external site: a2a-protocol.org)
- Repository: Repository (external site: github.com)
- Documentation: Governance (external site: github.com)
- License: LICENSE (external site: github.com)
- Release notes: Releases (external site: github.com)
Availability and license
Overall availability
The specification, SDKs, and samples are public. Interacting with a particular A2A agent is governed by that agent operator's own authentication and terms.16
Availability is separate from permission: read the license before using or redistributing.
Apache License 2.0 (external site: raw.githubusercontent.com)2
Plain-language guide to the Apache License 2.0
The A2A specification repository's LICENSE is the Apache License 2.0, and the README states the project is licensed under it; the Python SDK repository's LICENSE is also Apache 2.0. Other SDK repositories carry their own LICENSE files. The license does not cover agents or services built with the protocol.213
Component reuse rights
- weights
- Unknown — no complete fact-level rights review
- code
- Reviewed qualifying license recorded — check scope and conditions
- data
- Unknown — no complete fact-level rights review
- documentation
- Unknown — no complete fact-level rights review
No complete system-rights review is recorded for this release.
Public materials checklist
| Item | Status | Notes and evidence |
|---|---|---|
| Source codeIs the source code publicly readable? | Public | The specification is developed in a public repository; SDKs for Python, Go, JavaScript, Java, .NET, and Rust are in separate public repositories.1 |
| DocumentationIs user documentation published? | Public | Public documentation site with the full specification, tutorials, and guides.16 |
| InstallationAre installation instructions or packages publicly available? | Public | The README documents package installation for each SDK, for example pip install a2a-sdk for Python, npm for JavaScript, Maven for Java, NuGet for .NET, and cargo for Rust.1 |
| Supported platformsAre supported operating systems or hardware documented? | Public | Official SDKs cover Python, Go, JavaScript, Java, .NET, and Rust; the specification defines JSON-RPC, gRPC, and HTTP+JSON/REST bindings.16 |
| Release statusAre versioned releases published? | Public | The specification page presents version 1.0.0 as the latest released version. The repository's latest tagged release reviewed is v1.0.1, published May 28, 2026; v1.0.0 was published March 12, 2026.67 |
What it is useful for
Organization context
Provenance and derivatives
In the news
Nous Research releases Hermes Agent 0.20.0 with conversational voice and A2A v1.0 support
Nous Research published Hermes Agent v0.20.0 (tagged v2026.8.3) on GitHub on August 3, 2026, calling it "The Herald Release." The release notes list streaming conversational voice with barge-in and on-device wake words, and a new bundled plugin that implements the Agent-to-Agent (A2A) protocol v1.0 so Hermes can discover, talk to, and be driven by other A2A-compatible agents. The notes also list signed outbound webhooks, grounded research with citations and fact-checking, and a plugin SDK for the desktop app. USASI has not tested this release.
U.S. eligibility
Eligible · basis: U.S.-governed project
A2A is an open-source project under The Linux Foundation, which Google transferred to it in June 2025; the documentation site carries a Linux Foundation copyright, and the project's governance charter refers to a series agreement and series manager. In August 2026 it became a Growth Stage project of the Agentic AI Foundation, a directed fund of The Linux Foundation. The Linux Foundation describes itself as a 501(c)(6) nonprofit with a legal postal address in San Francisco, California. The Technical Steering Committee has eight company-held seats (AWS, Cisco, Google, IBM, Microsoft, Salesforce, SAP, and ServiceNow); this multi-organization governance was assessed, and eligibility rests on the documented Linux Foundation stewardship rather than on the composition of the committee or the nationality of contributors.18541011131415
Sources
This listing is not an endorsement, a safety assessment, or a federal approval.
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APA style
USASI. (2026, October 1). Agent2Agent (A2A) Protocol. United States of America Superintelligence. https://unitedstatesofamericasuperintelligence.com/open/a2a-protocol/
BibTeX
@misc{usasi_a2a_protocol,
author = {{USASI}},
title = {Agent2Agent (A2A) Protocol},
year = {2026},
month = oct,
howpublished = {\url{https://unitedstatesofamericasuperintelligence.com/open/a2a-protocol/}},
note = {United States of America Superintelligence. Last updated 2026-10-01}
}The date is when this page was last updated. Add the date you read it if your style needs one.
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