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<h2 align="center">✨ Awesome A2A (Agent2Agent Protocol) ✨</h2>
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A curated list of awesome resources, implementations, tools, and examples related to the Google Agent2Agent (A2A) Protocol for AI agent interoperability.
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## Contents
* [🤔 What is A2A? (Briefly)](#-what-is-a2a-briefly)
* [💡 Key Principles](#-key-principles)
* [⚙️ How Does A2A Work? (High Level)](#️-how-does-a2a-work-high-level)
* [🚀 Getting Started with A2A](#-getting-started-with-a2a)
* [🏛️ Official Resources](#️-official-resources)
* [📜 Specification & Core Concepts](#-specification--core-concepts)
* [⚙️ Implementations & Libraries](#️-implementations--libraries)
* [Official Samples](#official-samples)
* [Framework Integrations (Official Samples)](#framework-integrations-official-samples)
* [Community Implementations](#community-implementations)
* [🛠️ Tools & Utilities](#️-tools--utilities)
* [📚 Tutorials & Articles](#-tutorials--articles)
* [🎬 Demos & Examples](#-demos--examples)
* [🔗 Related Protocols & Concepts](#-related-protocols--concepts)
* [💬 Community](#-community)
* [Contributing](#contributing)
---
## 🤔 What is A2A? (Briefly)
A2A (Agent2Agent) is an **open protocol** from Google and partners enabling different **AI agents** (from various vendors/frameworks) to **communicate securely** and **collaborate on tasks**. It aims to break down silos between isolated agent systems, allowing for more complex cross-application automation.
**⭐ Official Website:** [google.github.io/A2A](https://google.github.io/A2A) | **⭐ Official GitHub:** [github.com/google/A2A](https://github.com/google/A2A)
## 💡 Key Principles
* **Simple:** Uses existing standards (HTTP, JSON-RPC, SSE).
* **Enterprise Ready:** Focuses on Auth, Security, Privacy, Monitoring.
* **Async First:** Handles long-running tasks & human-in-the-loop.
* **Modality Agnostic:** Supports Text, Files, Forms, Streams, etc.
* **Opaque Execution:** Agents interact without sharing internal logic/tools.
## ⚙️ How Does A2A Work? (High Level)
1. **Discovery:** Agents publish an `Agent Card` (JSON) describing capabilities, endpoint, and auth needs.
2. **Communication:** A `Client` agent sends a `Task` request (containing a `Message` with `Parts`) to a `Remote Agent (Server)` using HTTP/JSON-RPC 2.0.
3. **Execution & Response:** The Server processes the task, updating its `status`. It responds with the final status and any generated `Artifacts` (results, also containing `Parts`).
4. **Updates:** For long tasks, the Server can optionally stream `TaskStatusUpdateEvent` or `TaskArtifactUpdateEvent` via Server-Sent Events (SSE) or use Push Notifications.
*For details, see the [Official Technical Documentation](https://google.github.io/A2A/#/documentation).*
---
## 🚀 Getting Started with A2A
New to A2A? Here's a suggested path:
1. **Understand the Basics:** Read the sections above ([What is A2A?](#-what-is-a2a-briefly), [Key Principles](#-key-principles), [How it Works](#️-how-does-a2a-work-high-level)). Check the 📰 [Announcement Blog Post](https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/).
2. **Explore Core Concepts:** Dive into the 📖 [Official Technical Documentation](https://google.github.io/A2A/#/documentation), focusing on `Agent Card`, `Task`, `Message`, `Part`, and `Artifact`.
3. **See it in Action:** Watch the 🎥 [Official Demo Video](https://storage.googleapis.com/gweb-developer-goog-blog-assets/original_videos/A2A_demo_v4.mp4) and explore the code for the 🌐 [Multi-Agent Web App Demo](https://github.com/google/A2A/tree/main/demo).
4. **Run the Samples:** Clone the [Official Repo](https://github.com/google/A2A) and follow the instructions in `/samples` to run a client (like the CLI) and a sample agent (e.g., LangGraph or Genkit agent). See the [Official Samples](#official-samples) tables below for links.
5. **Review the Code:** Look at the `common` (Python) or `server`/`client` (JS/TS) libraries in the official samples to see how A2A communication is implemented.
6. **Try Building:** Adapt a sample or use a library to create your own basic A2A agent or client.
---
## 🏛️ Official Resources
* 📄 [A2A Protocol Website](https://google.github.io/A2A) - The main documentation site.
* 💻 [google/A2A GitHub Repository](https://github.com/google/A2A) - Source code for the spec, docs, and official samples.
* 📰 [Google Developers Blog Post](https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/) - Announcement blog post explaining the motivation and partners.
## 📜 Specification & Core Concepts
*(See [How Does A2A Work?](#️-how-does-a2a-work-high-level) above for summaries)*
* 📖 [A2A Technical Documentation](https://google.github.io/A2A/#/documentation) - **(Full Details)** Detailed explanation of actors, transport, auth, core objects (Task, Artifact, Message, Part), Agent Card, etc.
* 📄 [JSON Specification](https://github.com/google/A2A/tree/main/specification/json) - The raw JSON schema definition for A2A structures.
* 💡 [Key Principles (Docs)](https://google.github.io/A2A/#/documentation?id=key-principles) - Link to the principles section in the official docs.
* 🃏 [Agent Card Specification (Docs)](https://google.github.io/A2A/#/documentation?id=agent-card) - Link to the Agent Card section in the official docs.
* 🗺️ [Agent Discovery (Topic)](https://google.github.io/A2A/#/topics/agent_discovery.md) - Discussion on how clients can find agent cards.
* 🔔 [Push Notifications (Topic)](https://google.github.io/A2A/#/topics/push_notifications.md) - Details on the push notification mechanism.
* 🛡️ [Enterprise Readiness (Topic)](https://google.github.io/A2A/#/topics/enterprise_ready.md) - Discussion on security, auth, privacy aspects.
## ⚙️ Implementations & Libraries
#### Official Samples
*These demonstrate basic A2A client/server communication.*
| Language | Type | Framework | Description | Link |
| :--------- | :--------------- | :---------- | :---------------------------------------------- | :-------------------------------------------------------------------------------- |
| 🐍 Python | Common Library | - | Core HTTP, JSON-RPC, SSE handling | [Link](https://github.com/google/A2A/tree/main/samples/python/common) |
| 🐍 Python | Host (Client) | CLI | Command-line client example | [Link](https://github.com/google/A2A/tree/main/samples/python/hosts/cli) |
| 🐍 Python | Host (Agent) | ADK | Orchestrator agent delegating to A2A agents | [Link](https://github.com/google/A2A/tree/main/samples/python/hosts/multiagent) |
| 🚀 JS/TS | Server Library | Express | Core server implementation | [Link](https://github.com/google/A2A/tree/main/samples/js/src/server) |
| 🚀 JS/TS | Client Library | - | Client implementation | [Link](https://github.com/google/A2A/tree/main/samples/js/src/client) |
| 🚀 JS/TS | Host (Client) | CLI | Command-line client example | [Link](https://github.com/google/A2A/blob/main/samples/js/src/cli.ts) |
#### Framework Integrations (Official Samples)
*These show how agents built with specific frameworks can expose an A2A interface.*
| Language | Agent Framework | Agent Description | Key A2A Features Demonstrated | Link |
| :--------- | :-------------- | :------------------------------------------ | :-------------------------------------- | :----------------------------------------------------------------------------- |
| 🐍 Python | LangGraph | Currency conversion | Tools, Streaming, Multi-turn | [Link](https://github.com/google/A2A/tree/main/samples/python/agents/langgraph) |
| 🐍 Python | CrewAI | Image generation | Non-textual Artifacts (Files) | [Link](https://github.com/google/A2A/tree/main/samples/python/agents/crewai) |
| 🐍 Python | Google ADK | Expense reimbursement | Multi-turn, Forms (DataPart) | [Link](https://github.com/google/A2A/tree/main/samples/python/agents/google_adk)|
| 🚀 JS/TS | Genkit | Movie info / Code generation | Tools, Artifacts (Files), Async | [Link](https://github.com/google/A2A/tree/main/samples/js/src/agents) |
#### Community Implementations
* 🌟 _Your Framework/Language A2A Server/Client Library?_ - Add it here! See [CONTRIBUTING.md](CONTRIBUTING.md).
* <!-- TODO: Add community implementations -->
## 🛠️ Tools & Utilities
* 🔍 *Agent Discovery Services* - [Link] - Description (e.g., implementation of an 'Agent Catalog'). <!-- TODO -->
* ✅ *A2A Validation Tool* - [Link] - Tool to check compliance of an A2A endpoint. <!-- TODO -->
* 📊 *Monitoring/Tracing Adapters* - [Link] - Integrations for observability platforms. <!-- TODO -->
## 📚 Tutorials & Articles
* 📄 [Official A2A Conceptual Overview (README)](https://github.com/google/A2A#conceptual-overview) - High-level explanation in the official repo's README.
* 🚀 [Getting Started Guide (Official README)](https://github.com/google/A2A#getting-started) - Links to docs, spec, samples in the official repo's README.
* ✍️ *[Blog Post/Tutorial Title]* - [Link] - Description. <!-- TODO: Add community articles/guides here -->
## 🎬 Demos & Examples
* 🌐 [Official Multi-Agent Web App (Python/Mesop)](https://github.com/google/A2A/tree/main/demo) - Demonstrates the orchestrator agent interacting with multiple remote agents, rendering text, images, and forms. **Requires running Python code.**
* 🎥 [Official Demo Video (Section Link)](https://github.com/google/A2A#see-a2a-in-action) - Link to the video embedded in the official repository's README.
## 🔗 Related Protocols & Concepts
* 📦 [Model Context Protocol (MCP)](https://github.com/modelcontextprotocol/servers) - Complementary protocol focused on providing tools/context *to* agents. ([A2A and MCP Discussion](https://google.github.io/A2A/#/topics/a2a_and_mcp.md)).
* 📞 *Function Calling / Tool Use Standards* - [Link] - Relevant standards (e.g., OpenAI function calling). <!-- TODO -->
## 💬 Community
* 🐞 [google/A2A GitHub Issues](https://github.com/google/A2A/issues) - For reporting bugs or suggesting protocol improvements.
* 🔒 [Private Feedback Form](https://docs.google.com/forms/d/e/1FAIpQLScS23OMSKnVFmYeqS2dP7dxY3eTyT7lmtGLUa8OJZfP4RTijQ/viewform) - Google form for private feedback.
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## Contributing
Contributions are welcome! 🙌 Please read the [contributing guidelines](CONTRIBUTING.md) first. Let's build this list together!
