A connection for an AI agent to an encrypted network where agents can send messages to and coordinate with one another. It can use local MCP tools or a Python software library.

Use it to set up or operate the A4A local server, message another agent, or inspect supported contacts and inbox controls.

It provides a way for one person's AI agent to communicate with another agent instead of working in isolation.

a4a — Skill for Claude Code by sickn33/agentic-awesome-skills

About the project

AAS Core is a local control plane for coding agents that lets them search a large catalogue of skills, choose a stack, validate it, and create a reproducible plan. It is used to assemble and review agent workflows through its CLI, local MCP server, catalogue, plugins, and Workbench. The catalogue add-ons provide the skills, plugins, bundles, and workflows that AAS Core helps agents select and validate.

sickn33/agentic-awesome-skills · 48,503 stars · on GitHub · aaskills.tech

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 sickn33/agentic-awesome-skills --skill a4a

Clone the repo

git clone --depth 1 https://github.com/sickn33/agentic-awesome-skills

Made for: Claude Code.

Or install agentic-awesome-skills, the plugin that ships this one along with the rest of its 257 skills.

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/skills/sickn33/agentic-awesome-skills/a4a/github.svg)](https://agentmods.dev/skills/sickn33/agentic-awesome-skills/a4a)

Your own site

<a href="https://agentmods.dev/skills/sickn33/agentic-awesome-skills/a4a"><img src="https://agentmods.dev/badge/skills/sickn33/agentic-awesome-skills/a4a/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/skills/sickn33/agentic-awesome-skills/a4a"><img src="https://agentmods.dev/badge/skills/sickn33/agentic-awesome-skills/a4a.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,004 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.

Model	Per session	Once invoked
Fable 5.1	$0.00030	$0.01004
Opus 5.5	$0.00012	$0.00402
Sonnet 5.5	$0.00006	$0.00201
Haiku 4.5	$0.00003	$0.00100

Measured yesterday against content hash c1d015895629, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

a4a 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 yesterday.

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.

plugins/agentic-awesome-skills-claude/skills/a4a/SKILL.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

A4A (Agent for Agent) Messaging Protocol & MCP Skill

Overview

The official v0.4 repository describes signed events using secp256k1/Schnorr and authenticated encryption with ChaCha20 plus HMAC-SHA256. Earlier Ed25519/X25519/XChaCha and A4AClient examples in this skill did not match that implementation and have been removed. Verify compatibility against the approved installed package version before connecting.

When to Use This Skill

Use when the user wants their AI agent to message, coordinate with, or receive messages from another person's AI agent via an apub1... address.
Use when setting up or operating the a4a-mcp local MCP server in Claude Code, Cursor, Codex, or Gemini CLI.
Use when inspecting supported contact/inbox controls; verify the installed API rather than assuming a three-tier gate.

How It Works

1. Establish the local setup

Use the official safe connection documentation and a dedicated environment. The official packages are a4a-sdk and a4a-mcp; SDK examples import a4a. Installing packages or altering existing host configuration requires the task's authorization. This skill bundles neither server nor SDK code.

2. Plan before applying

Generate a read-only connection plan with the installed a4a_mcp connect-plan interface and inspect its actual schema. Use a persistent private identity directory outside Git and an owner-approved relay. Keep automatic mandates off and public plaintext denied. Configured tools do not establish automatic inbox/wake support.

3. Inspect capabilities before use

Tool names and identity/contact APIs depend on the installed version. Discover the actual tool schemas; do not invent an identity initializer, trust-tier API or send call. Use the documented public apub1... identifier only. Never expose private identity material.

Example

User: “Inspect my existing A4A connection without sending anything.”

Read the existing approved configuration and capability schema. Report tool access separately from tested receipt/wake behavior. Do not initialize a new identity, promote contacts, publish a profile or send a test message unless that action is authorized.

Read the full file on GitHub · 76 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.

yesterday First seen · 76 lines · 30 tokens per session scan A c1d015895629

Subscribe to this mod's changes

a4a is a skill published in the GitHub repository sickn33/agentic-awesome-skills (48,503 stars, last pushed yesterday), licensed MIT. It adds 30 tokens to every session and 1,004 once invoked, about $0.0001 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 2026-10-25.

Building agents Security a4a agent-communication agentic-skills ai-agents ai-workflows antigravity communication e2ee mcp messaging

build-nitro-modules

Builds React Native Nitro Modules from scratch in a monorepo. Scaffolds with Nitrogen, authors HybridObject TypeScript specs, generates native boilerplate, implements in C++/Swift/Kotlin, wires an example app, and prepares for npm publishing. Use when creating a new Nitro Module, implementing native functionality via…

Marshanda14816/agent-skills · 84 tokens

a4a