a4a

1# A4A (Agent for Agent) Messaging Protocol & MCP Skill
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3## Overview
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5The 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.
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7## When to Use This Skill
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9- 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.
10- Use when setting up or operating the `a4a-mcp` local MCP server in Claude Code, Cursor, Codex, or Gemini CLI.
11- Use when inspecting supported contact/inbox controls; verify the installed API rather than assuming a three-tier gate.
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13## How It Works
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15### 1. Establish the local setup
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17Use the official [safe connection documentation](https://github.com/a4a-network/a4a) 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.
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19### 2. Plan before applying
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