What is a2a-java AGENTS.md?

Project instructions for a2a-java, a multi-module Java SDK for the Agent2Agent Protocol, which lets AI agents communicate through JSON-RPC, gRPC, and REST.

Use them to build and navigate client, server, transport, protocol, reference-server, and compatibility modules.

They explain the modules, Java requirement, build command, and protocol-related structure so changes land in the right part of the SDK.

How a2aproject/a2a-java configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to a2aproject/a2a-java. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/a2aproject/a2a-java/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/a2aproject/a2a-java

Made for: Codex, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/instructions/a2aproject/a2a-java/agents-md/github.svg)](https://agentmods.dev/instructions/a2aproject/a2a-java/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/a2aproject/a2a-java/agents-md"><img src="https://agentmods.dev/badge/instructions/a2aproject/a2a-java/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/instructions/a2aproject/a2a-java/agents-md"><img src="https://agentmods.dev/badge/instructions/a2aproject/a2a-java/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 1,850 This file is loaded in full into every session.

When invoked 1,850 The same file — it is already loaded in full.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.01850	$0.01850
Opus 5.5	$0.00740	$0.00740
Sonnet 5.5	$0.00370	$0.00370
Haiku 4.5	$0.00185	$0.00185

Measured 10d ago against content hash 12a8dfa68de1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

a2a-java AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

AGENTS.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md

Project Overview

Java SDK for the Agent2Agent (A2A) Protocol. Multi-module Maven project (org.a2aproject.sdk group) providing client and server libraries for A2A agent communication over JSON-RPC, gRPC, and REST transports.

Build

Requires Java 17+. Tests output is redirected to files by default.

mvn clean install

Project Structure

spec/ — A2A specification types (Java records for the protocol)
spec-grpc/ — gRPC protobuf definitions and generated classes
common/ — Shared utilities used across modules
client/ — Client SDK
- base/ — Core client API
- transport/spi/ — Transport SPI
- transport/jsonrpc/, transport/grpc/, transport/rest/ — Transport implementations
server-common/ — Server-side core (AgentExecutor, TaskStore, QueueManager)
transport/ — Server transport layer (jsonrpc, grpc, rest)
http-client/ — HTTP client abstraction
jsonrpc-common/ — Shared JSON-RPC utilities
reference/ — Reference server implementations built on Quarkus
- common/, jsonrpc/, grpc/, rest/
- multiversion-jsonrpc/, multiversion-rest/ — Multi-version dispatching (v1.0 + v0.3)
tck/ — Technology Compatibility Kit (protocol conformance tests)
tests/ — Integration and server-common tests
- server-common/ — Server-common integration tests
- multiversion/ — Multi-version integration tests (jsonrpc, rest, grpc)
extras/ — Optional add-ons
- common/ — Shared classes across extras modules
- opentelemetry/ — OpenTelemetry integration
- task-store-database-jpa/ — JPA-backed task store
- push-notification-config-store-database-jpa/ — JPA-backed push notification config store
- queue-manager-replicated/ — Kafka-based replicated queue manager
- http-client-vertx/ — Vert.x HTTP client
- http-client-android/ — Android HTTP client
compat-0.3/ — Backward compatibility layer for A2A protocol v0.3
integrations/ — Runtime integrations (e.g., MicroProfile Config)
test-utils-docker/ — Test utilities for conditional Docker-based test execution
boms/ — Bill of Materials POMs (sdk, extras, reference, test-utils)
examples/ — Sample applications (helloworld, cloud-deployment)

Read the full file on GitHub · 132 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

10d ago Changed · +35 tokens per session 12a8dfa68de1
2mo ago First seen · 132 lines · 1,815 tokens per session scan A b15c2fbfa073

Subscribe to this mod's changes

a2a-java AGENTS.md is an instructions file published in the GitHub repository a2aproject/a2a-java (509 stars, last pushed yesterday), licensed Apache-2.0. It adds 1,850 tokens to every session, about $0.0074 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Building agents Java Languages a2a a2a-client a2a-server agent2agent ai hacktoberfest

a2a-java AGENTS.md next to 6 instructions from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
a2a-java AGENTS.mda2aproject/a2a-java	Instructions file	509	yesterday	Apache-2.0	A	1,850	Codex, OpenCode
vscode buildNext.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	9,719	GitHub Copilot
next.js AGENTS.mdvercel/next.js	Instructions file	143k	today	MIT	A	7,461	Codex, OpenCode
langchain AGENTS.mdlangchain-ai/langchain	Instructions file	149k	yesterday	MIT	A	4,680	Codex, OpenCode
vscode oss-third-party-notices.instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	5,516	GitHub Copilot
vscode copilot-instructions.mdmicrosoft/vscode	Instructions file	195k	yesterday	MIT	A	3,093	GitHub Copilot
deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness	Instructions file	274k	2d ago	MIT	A	4,313	Codex, OpenCode

a2a-java: Instructions file for Codex