a2a-protocol

a2a-protocol is a skill for Claude Code, Codex from Lord1Egypt/awesome-skill-forge. It costs 96 tokens per session (3,480 once invoked), scanned A, original, MIT.

A guide for connecting AI agents through the Agent2Agent (A2A) protocol, a standard way for agents to discover one another and exchange tasks and data. It covers clients, servers, capability descriptions, task updates, files, and different communication formats.

In plain words
What is it for?
Use it to build an A2A client or server, publish an AgentCard describing an agent’s capabilities, or add A2A support to an existing agent framework.
Why use it?
It removes the guesswork from making separately built agents work together. It explains the order of protocol operations and the concepts needed for multi-step communication.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build an A2A client or server, publish an AgentCard describing an agent’s capabilities, or add A2A support to an existing agent framework.

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Install with agentmods
npx agentmods add skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Lord1Egypt/awesome-skill-forge --skill a2a-agent-protocol
Clone the repo
git clone --depth 1 https://github.com/Lord1Egypt/awesome-skill-forge

Made for: Claude Code, Codex.

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.

agentmods badge for a2a-protocol

README.md
[![agentmods](https://agentmods.dev/badge/skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol/github.svg)](https://agentmods.dev/skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol)
Your own site
<a href="https://agentmods.dev/skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol"><img src="https://agentmods.dev/badge/skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol/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.

agentmods 80×15 button for a2a-protocol

Your own site · 80×15
<a href="https://agentmods.dev/skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol"><img src="https://agentmods.dev/badge/skills/lord1egypt/awesome-skill-forge/a2a-agent-protocol.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 96 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,480 The whole file, excluding the scripts and references it only reads on demand.
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00096 $0.03480
Opus 5 $0.00048 $0.01740
Sonnet 5 $0.00019 $0.00696
Haiku 4.5 $0.00010 $0.00348

Measured 9d ago against content hash e2a1d1653961, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

a2a-protocol 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 9d 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.

community/clawhub/a/a2a-agent-protocol/SKILL.md · 306 lines

How it starts

The opening of the file, as written. The whole thing — 306 lines — stays where its author put it; the contents beside it link to each section on GitHub.

A2A Protocol Skill

An AI agent skill for building, connecting, and operating A2A-compliant agents. This skill is the definitive guide for agents participating in the Agent2Agent protocol ecosystem.

Core Position

This skill is NOT a general API wrapper — it is a protocol education and implementation guide. It teaches agents what A2A is, how to structure AgentCards for discovery, which operations to perform in which order, and how to handle the multi-turn task lifecycle.

This skill is NOT framework-specific. It guides agents regardless of whether they are built with LangGraph, BeeAI, Google ADK, or custom code. The A2A protocol is language-agnostic.

This skill covers the JSON-RPC 2.0 over HTTP binding (the most common) plus key concepts for gRPC and HTTP+REST bindings.

What Problem This Solves

AI agents today operate in silos. Even when they share the same infrastructure, they have no standard way to:

  • Discover what capabilities other agents expose
  • Send a task to a remote agent and track its lifecycle
  • Handle streaming updates or push notifications from a remote agent
  • Exchange files, structured data, or multi-part messages

The A2A protocol solves all of the above. This skill makes an AI agent A2A-aware.

Modes

/a2a-protocol

Default mode. Learn A2A concepts, data structures, and operation semantics.

Preferred opening: "The A2A protocol enables agents to discover each other and collaborate without exposing internal state. Here is the protocol overview:"

Use it when:

  • The user asks what A2A is, how it works, or why it matters
  • You need to explain the difference between A2A and MCP
  • You want to understand the AgentCard structure and discovery mechanism
  • You need to understand the full task lifecycle (submitted → working → completed)

/a2a-protocol build-card

Generate an AgentCard JSON for the agent. The AgentCard is the public identity document that other agents use to discover capabilities, auth requirements, and connection endpoints.

Read the full file on GitHub · 306 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.

  1. 9d ago First seen · 306 lines · 96 tokens per session scan A e2a1d1653961

Subscribe to this mod's changes

a2a-protocol is a skill published in the GitHub repository Lord1Egypt/awesome-skill-forge (2 stars, last pushed 3mo ago), licensed MIT. It adds 96 tokens to every session and 3,480 once invoked, about $0.0005 per session on Opus 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 2026-08-31.

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