Agent Protocol

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Introduction

Agent Protocol provides protocol SDKs and a service registry for agent interoperability in the openJiuwen ecosystem. It helps developers connect agents to tools, communicate with remote agents, discover available services, and enforce verifiable user authorization before sensitive operations.

An agent application needs more than a model and task logic: it needs a way to access external capabilities, locate suitable collaborators, exchange messages and task results, and constrain what it can execute on a user’s behalf. This repository addresses these needs through four complementary components: MCP C++ SDK, A2A C++ SDK, A2X Registry, and A4P Python SDK. Developers can choose individual components or combine them according to their integration needs.

Core Capabilities

Tool and resource integration with MCP

The Model Context Protocol (MCP) C++ SDK provides both client and server capabilities, supporting Streamable HTTP and stdio transports. Developers can expose tools, resources, and prompts through an MCP server, or build a client that connects to existing MCP services. The SDK also includes support for authentication, sampling, progress notifications, and roots.

Agent communication with A2A

The Agent2Agent (A2A) C++ SDK implements agent communication over HTTP and JSON-RPC. Clients can discover Agent Cards, send messages, query or cancel tasks, and receive streaming events. Servers can register an AgentExecutor, manage task lifecycles, and expose JSON-RPC endpoints, with extension points such as request interceptors and custom task stores.

Service registration and discovery with A2X

A2X Registry manages agents and services that agents can invoke. It supports registration and deregistration, field-based queries, service-card updates, online/busy/offline states, ownership-based access control, and short-lived reservation leases for Agent Team coordination.

For capability discovery, A2X search combines an automatically constructed hierarchical capability catalog with LLM-guided semantic navigation, allowing agents to locate services from natural-language requests. The registry also provides optional vector search, dataset isolation, HTTP APIs, a Python client, and a web UI for service management and search exploration. A2X search and catalog construction require an LLM configuration; basic registry operations do not.

Verifiable authorization with A4P

The Agentic Authentication, Authorization, and Audit Protocol (A4P) Python SDK supports Operation Mandates for specific operations and Intent Mandates/Tokens that allow repeated execution within specified operation types and parameter constraints. It separates the Agent, A4P Server, local User Authorizer, and protected Tool Server so that authorization checks are enforced outside the agent’s decision-making logic.

The SDK provides Ed25519-signed authorization objects, Ed25519 and WebAuthn/passkey user-signature methods, parameter-scope checks, and execution limits with SQLite-backed atomic consumption. Its two-stage prepare/complete interfaces support asynchronous user confirmation and integration with existing tool services.

Choosing a Component

Each component addresses a different integration need and can be used independently, without adopting the others.

Repository Layout

agent-protocol/
├── MCP/cpp-sdk/          # MCP C++ client/server SDK and examples
├── A2A/cpp-sdk/          # A2A C++ client/server SDK and examples
├── AgentRegistry/       # A2X registry, Python client, web UI, and documentation
└── A4P-python-sdk/       # A4P Python SDK, protocol documentation, and examples

Getting Started

Clone the repository, then follow the guide for the component you need:

git clone https://github.com/openJiuwen-ai/agent-protocol.git
cd agent-protocol

The components are built and installed separately. See each guide for complete dependency requirements and platform-specific instructions.

Documentation

• MCP: API reference · Dependencies · Testing
• A2A: API reference · Dependencies · Error handling
• A2X: Registry guide · Python client · Agent Team deployment
• A4P: Protocol · SDK design · MCP integration example

Contributing

We welcome all forms of contribution, including but not limited to:

• Reporting issues and suggesting features
• Improving documentation
• Submitting code
• Sharing usage experience

License

This project is licensed under the Apache-2.0 License.

This product serves solely as a workflow orchestration tool and does not embed any AI model capabilities. When users integrate AI models for specific business scenarios, they shall bear full responsibility for compliance obligations under the EU AI Act and other relevant regulatory frameworks.