Implementing A2A protocol in NET: A Practical Guide
As AI systems mature into multi‑agent ecosystems, the need for agents to communicate reliably and securely has become fundamental. Traditionally, agents built on different frameworks like Semantic Kernel, LangChain, custom orchestrators, or enterprise APIs do not share a common communication model. This creates brittle integrations, duplicate logic, and siloed intelligence. The Agent‑to‑Agent Standard (A2AS) addresses this gap by defining a universal, vendor‑neutral protocol for structured agent interoperability. A2A establishes a common language for agents, built on familiar web primitives: JSON‑RPC 2.0 for messaging and HTTPS for transport. Each agent exposes a machine‑readable Agent Card describing its capabilities, supported input/output modes, and authentication requirements. Interactions are modeled as Tasks, which support synchronous, streaming, and long‑running workflows. Messages exchanged within a task contain Parts; text, structured data, files, or streams, that allow agents to collaborate without exposing internal implementation details. By standardizing discovery, communication, authentication, and task orchestration, A2A enables organizations to build composable AI architectures. Specialized agents can coordinate deep reasoning, planning, data retrieval, or business automation regardless of their underlying frameworks or hosting environments. This modularity, combined with industry adoption and Linux Foundation governance, positions A2A as a foundational protocol for interoperable AI systems. A2AS in .NET — Implementation Guide Prerequisites • .NET 8 SDK • Visual Studio 2022 (17.8+) • A2A and A2A.AspNetCore packages • Curl/Postman (optional, for direct endpoint testing) The open‑source A2A project provides a full‑featured .NET SDK, enabling developers to build and host A2A agents using ASP.NET Core or integrate with other agents as a client. Two A2A and A2A.AspNetCore packages power the experience. The SDK offers: A2AClient - to call remote agents TaskManager - to manage incoming tasks & message routing AgentCard / Message / Task models - strongly typed protocol objects MapA2A() - ASP.NET Core router integration that auto‑generates protocol endpoints This allows you to expose an A2A‑compliant agent with minimal boilerplate. Project Setup Create two separate projects: CurrencyAgentService → ASP.NET Core web project that hosts the agent A2AClient → Console app that discovers the agent card and sends a message Install the packages from the pre-requisites in the above projects. Building a Simple A2A Agent (Currency Agent Example) Below is a minimal Currency Agent implemented in ASP.NET Core. It responds by converting amounts between currencies. Step 1: In CurrencyAgentService project, create the CurrencyAgentImplementation class to implement the A2A agent. The class contains the logic for the following: a) Describing itself (agent “card” metadata). b) Processing the incoming text messages like “100 USD to EUR”. c) Returning a single text response with the conversion. The AttachTo(ITaskManager taskManager) method hooks two delegates on the provided taskManager - a) OnAgentCardQuery → GetAgentCardAsync: returns agent metadata. b) OnMessageReceived → ProcessMessageAsync: handles incoming messages and produces a response. Step 2: In the Program.cs of the Currency Agent Solution, create a TaskManager , and attach the agent to it, and expose the A2A endpoint. Typical flow: GET /agent → A2A host asks OnAgentCardQuery → returns the card POST /agent with a text message → A2A host calls OnMessageReceived → returns the conversion text. All fully A2A‑compliant. Calling an A2A Agent from .NET To interact with any A2A‑compliant agent from .NET, the client follows a predictable sequence: identify where the agent lives, discover its capabilities through the Agent Card, initialize a correctly configured A2AClient, construct a well‑formed message, send it asynchronously, and finally interpret the structured response. This ensures your client is fully aligned with the agent’s advertised contract and remains resilient as capabilities evolve. Below are the steps implemented to call the A2A agent from the A2A client: Identify the agent endpoint: Why: You need a stable base URL to resolve the agent’s metadata and send messages. What: Construct a Uri pointing to the agent service, e.g., https://localhost:7009/agent. Discover agent capabilities via an Agent Card. Why: Agent Cards provide a contract: name, description, final URL to call, and features (like streaming). This de-couples your client from hard-coded assumptions and enables dynamic capability checks. What: Use A2ACardResolver with the endpoint Uri, then call GetAgentCardAsync() to obtain an AgentCard. Initialize the A2AClient with the resolved URL. Why: The client encapsulates transport details and ensures messages are sent to the correct agent endpoint, which may differ from the discovery URL. What: Create A2AClient using new Uri (currencyCard.Url) from the Agent Card for correctness. Construct a well-formed agent request message. Why: Agents typically require structured messages for roles, traceability, and multi-part inputs. A unique message ID supports deduplication and logging. What: Build an AgentMessage: • Role = MessageRole.User clarifies intent. • MessageId = Guid.NewGuid().ToString() ensures uniqueness. • Parts contains content; for simple queries, a single TextPart with the prompt (e.g., “100 USD to EUR”). Package and send the message. Why: MessageSendParams can carry the message plus any optional settings (e.g., streaming flags or context). Using a dedicated params object keeps the API extensible. What: Wrap the AgentMessage in MessageSendParams and call SendMessageAsync(...) on the A2AClient. Outcome: Await the asynchronous response to avoid blocking and to stay scalable. Interpret the agent response. Why: Agents can return multiple Parts (text, data, attachments). Extracting the appropriate part avoids assumptions and keeps your client robust. What: Cast to AgentMessage, then read the first TextPart’s Text for the conversion result in this scenario. Best Practices 1. Keep Agents Focused and Single‑Purpose Design each agent around a clear, narrow capability (e.g., currency conversion, scheduling, document summarization). Single‑responsibility agents are easier to reason about, scale, and test, especially when they become part of larger multi‑agent workflows. 2. Maintain Accurate and Helpful Agent Cards The Agent Card is the first interaction point for any client. Ensure it accurately reflects: Supported input/output formats Streaming capabilities Authentication requirements (if any) Version information A clean and honest card helps clients integrate reliably without guesswork. 3. Prefer Structured Inputs and Outputs Although A2A supports plain text, using structured payloads through DataPart objects significantly improves consistency. JSON inputs and outputs reduce ambiguity, eliminate prompt‑engineering edge cases, and make agent behavior more deterministic especially when interacting with other automated agents. 4. Use Meaningful Task States Treat A2A Tasks as proper state machines. Transition through states intentionally (Submitted → Working → Completed, or Working → InputRequired → Completed). This gives clients clarity on progress, makes long‑running operations manageable, and enables more sophisticated control flows. 5. Provide Helpful Error Messages Make use of A2A and JSON‑RPC error codes such as -32602 (invalid input) or -32603 (internal error), and include additional context in the error payload. Avoid opaque messages, error details should guide the client toward recovery or correction. 6. Keep Agents Stateless Where Possible Stateless agents are easier to scale and less prone to hidden failures. When state is necessary, ensure it is stored externally or passed through messages or task contexts. For local POCs, in‑memory state is acceptable, but design with future statelessness in mind. 7. Validate Input Strictly Do not assume incoming messages are well‑formed. Validate fields, formats, and required parameters before processing. For example, a currency conversion agent should confirm both currencies exist and the value is numeric before attempting a conversion. 8. Design for Streaming Even if Disabled Streaming is optional, but it’s a powerful pattern for agents that perform progressive reasoning or long computations. Structuring your logic so it can later emit partial TextPart updates makes it easy to upgrade from synchronous to streaming workflows. 9. Include Traceability Metadata Embed and log identifiers such as TaskId, MessageId, and timestamps. These become crucial for debugging multi‑agent scenarios, improving observability, and correlating distributed workflows—especially once multiple agents collaborate. 10. Offer Clear Guidance When Input Is Missing Instead of returning a generic failure, consider shifting the task to InputRequired and explaining what the client should provide. This improves usability and makes your agent self‑documenting for new consumers.How to use Comments as Prompts in GitHub Copilot for Visual Studio
GitHub Copilot is a coding assistant powered by Artificial Intelligence (AI), which can run in various environments and help you be more efficient in your daily coding tasks. In this new short video, Bruno shows you how to use inline comments to generate code with GitHub Copilot.Study Buddy: Learning Data Science and Machine Learning with an AI Sidekick
If you've ever wished for a friendly companion to guide you through the world of data science and machine learning, you're not alone. As part of the "For Beginners" curriculum, I recently built a Study Buddy Agent, an AI-powered assistant designed to help learners explore data science interactively, intuitively, and joyfully. Why a Study Buddy? Learning something new can be overwhelming, especially when you're navigating complex topics like machine learning, statistics, or Python programming. The Study Buddy Agent is here to change that. It brings the curriculum to life by answering questions, offering explanations, and nudging learners toward deeper understanding, all in a conversational format. Think of it as your AI-powered lab partner: always available, never judgmental, and endlessly curious. Built with chatmodes, Powered by Purpose The agent lives inside a .chatmodes file in the https://github.com/microsoft/Data-Science-For-Beginners/blob/main/.github/chatmodes/study-mode.chatmode.md. This file defines how the agent behaves, what tone it uses, and how it interacts with learners. I designed it to be friendly, encouraging, and beginner-first—just like the curriculum itself. It’s not just about answering questions. The Study Buddy is trained to: Reinforce key concepts from the curriculum Offer hints and nudges when learners get stuck Encourage exploration and experimentation Celebrate progress and milestones What’s Under the Hood? The agent uses GitHub Copilot's chatmode, which allows developers to define custom behaviors for AI agents. By aligning the agent’s responses with the curriculum’s learning objectives, we ensure that learners stay on track while enjoying the flexibility of conversational learning. How You Can Use It YouTube Video here: Study Buddy - Data Science AI Sidekick Clone the repo: Head to the https://github.com/microsoft/Data-Science-For-Beginners and clone it locally or use Codespaces. Open the GitHub Copilot Chat, and select Study Buddy: This will activate the Study Buddy. Start chatting: Ask questions, explore topics, and let the agent guide you. What’s Next? This is just the beginning. I’m exploring ways to: Expand the agent to other beginner curriculums (Web Dev, AI, IoT) Integrate feedback loops so learners can shape the agent’s evolution Final Thoughts In my role, I believe learning should be inclusive, empowering, and fun. The Study Buddy Agent is a small step toward that vision, a way to make data science feel less like a mountain and more like a hike with a good friend. Try it out, share your feedback, and let’s keep building tools that make learning magical. Join us on Discord to share your feedback.Announcing the Powerful Devs Conference + Hack Together 2025
Discover the potential of Microsoft Power Platform at this global event starting Feb 12, 2025! Learn from experts, explore tools like Power Apps, AI Builder, and Copilot Studio, and create innovative solutions during the two-week hackathon. Prizes await the best projects across 8 categories. 🌟 Build. Innovate. Hack Together. 👉 Register now: aka.ms/powerfuldevs Your future in enterprise app development starts here!GitHub Copilot Global Bootcamp
GitHub Copilot Bootcamp is a series of four live classes designed to teach you tips and best practices for using GitHub Copilot. Discover how to create quick solutions, automate repetitive tasks, and collaborate effectively on projects. REGISTER NOW! Why participate? GitHub Copilot is not just a code suggestion tool, but a programming partner that understands your needs and accelerates your work. By participating in the bootcamp, you will have the opportunity to: Master the creation of effective prompts. Learn to develop web applications using AI. Discover how to automate tests and generate documentation. Explore collaboration practices and automated deployment. Learn in your local language We will also have editions in other languages besides English: Spanish: https://aka.ms/GitHubCopilotBootcampLATAM Brazilian Portuguese: https://aka.ms/GitHubCopilotBootcampBrasil Chinese: https://aka.ms/GitHubCopilotBootcampChina Agenda The English sessions are scheduled for 12pm PST, 3pm ET, 2pm CT, and 1pm MT. 📅 February 4, 2025 Prompt Engineering with GitHub Copilot Learn how GitHub Copilot works and master responsible AI to boost your productivity. 📅 February 6, 2025 Building an AI Web Application with Python and Flask Create amazing projects with AI integration and explore using GitHub Copilot to simplify tasks. 📅 February 11, 2025 Productivity with GitHub Copilot: Docs and Unit Tests Automate documentation and efficiently develop tests by applying concepts directly to real-world projects. 📅 February 13, 2025 Collaboration and Deploy with GitHub Copilot Learn to create GitHub Actions, manage pull requests, and use GitHub Copilot for Azure for deployment. Who can participate? If you are a developer, student, or technology enthusiast, this bootcamp is for you. The classes are designed to cater to both beginners and experienced professionals. Secure your spot now and start your journey to mastering GitHub Copilot! 👉 REGISTER NOW!How to Install GitHub Copilot in Visual Studio
GitHub Copilot is a coding assistant powered by Artificial Intelligence (AI), which can run in various environments and help you be more efficient in your daily coding tasks. In this new series of content, we will show you how GitHub Copilot works in Visual Studio specifically and how it helps you being more productive.Microsoft AI Agents Hack April 8-30th 2025
Build, Innovate, and #Hacktogether Learn from 20+ expert-led sessions streamed live on YouTube, covering top frameworks like Semantic Kernel, Autogen, the new Azure AI Agents SDK and the Microsoft 365 Agents SDK. Get hands-on experience, unleash your creativity, and build powerful AI agents—then submit your hack for a chance to win amazing prizes! Key Dates Expert sessions: April 8th 2025 – April 30th 2025 Hack submission deadline: April 30th 2025, 11:59 PM PST Don't miss out — join us and start building the future of AI! Registration Register now! That form will register you for the hackathon. Afterwards, browse through the live stream schedule below and register for the sessions you're interested in. Once you're registered, introduce yourself and look for teammates! Project Submission Once your hack is ready, follow the submission process. Prizes and Categories Projects will be evaluated by a panel of judges, including Microsoft engineers, product managers, and developer advocates. Judging criteria will include innovation, impact, technical usability, and alignment with corresponding hackathon category. Each winning team in the categories below will receive a prize. Best Overall Agent - $20,000 Best Agent in Python - $5,000 Best Agent in C# - $5,000 Best Agent in Java - $5,000 Best Agent in JavaScript/TypeScript - $5,000 Best Copilot Agent (using Microsoft Copilot Studio or Microsoft 365 Agents SDK) - $5,000 Best Azure AI Agent Service Usage - $5,000 Each team can only win in one category. All participants who submit a project will receive a digital badge. Stream Schedule The series starts with a kick-off for all developers, and then dives into specific tracks for Python, Java, C#, and JavaScript developers. The Copilots track will focus on building intelligent copilots with Microsoft 365 and Copilot Studio. English Week 1: April 8th-11th Day/Time Topic Track 4/8 09:00 AM PT AI Agents Hackathon Kickoff All 4/9 09:00 AM PT Build your code-first app with Azure AI Agent Service Python 4/9 12:00 PM PT AI Agents for Java using Azure AI Foundry Java 4/9 03:00 PM PT Build your code-first app with Azure AI Agent Service Python 4/10 04:00 AM PT Building Secure and Intelligent Copilots with Microsoft 365 Copilots 4/10 09:00 AM PT Overview of Microsoft 365 Copilot Extensibility Copilots 4/10 12:00 PM PT Transforming business processes with multi-agent AI using Semantic Kernel Python 4/10 03:00 PM PT Build your code-first app with Azure AI Agent Service (.NET) C# Week 2: April 14th-18th Day/Time Topic Track 4/15 07:00 AM PT Your first AI Agent in JS with Azure AI Agent Service JS 4/15 09:00 AM PT Building Agentic Applications with AutoGen v0.4 Python 4/15 12:00 PM PT AI Agents + .NET Aspire C# 4/15 03:00 PM PT Prototyping AI Agents with GitHub Models Python 4/16 04:00 AM PT Multi-agent AI apps with Semantic Kernel and Azure Cosmos DB C# 4/16 06:00 AM PT Building declarative agents with Microsoft Copilot Studio & Teams Toolkit Copilots 4/16 09:00 AM PT Building agents with an army of models from the Azure AI model catalog Python 4/16 12:00 PM PT Multi-Agent API with LangGraph and Azure Cosmos DB Python 4/16 03:00 PM PT Mastering Agentic RAG Python 4/17 06:00 AM PT Build your own agent with OpenAI, .NET, and Copilot Studio C# 4/17 09:00 AM PT Building smarter Python AI agents with code interpreters Python 4/17 12:00 PM PT Building Java AI Agents using LangChain4j and Dynamic Sessions Java 4/17 03:00 PM PT Agentic Voice Mode Unplugged Python Week 3: April 21st-25th Day/Time Topic Track 4/21 12:00 PM PT Knowledge-augmented agents with LlamaIndex.TS JS 4/22 06:00 AM PT Building a AI Agent with Prompty and Azure AI Foundry Python 4/22 09:00 AM PT Real-time Multi-Agent LLM solutions with SignalR, gRPC, and HTTP based on Semantic Kernel Python 4/22 10:30 AM PT Learn Live: Fundamentals of AI agents on Azure - 4/22 12:00 PM PT Demystifying Agents: Building an AI Agent from Scratch on Your Own Data using Azure SQL C# 4/22 03:00 PM PT VoiceRAG: talk to your data Python 4/14 06:00 AM PT Prompting is the New Scripting: Meet GenAIScript JS 4/23 09:00 AM PT Building Multi-Agent Apps on top of Azure PostgreSQL Python 4/23 12:00 PM PT Agentic RAG with reflection Python 4/23 03:00 PM PT Multi-source data patterns for modern RAG apps C# 4/24 09:00 AM PT Extending AI Agents with Azure Functions Python, C# 4/24 12:00 PM PT Build real time voice agents with Azure Communication Services Python 4/24 03:00 PM PT Bringing robots to life: Real-time interactive experiences with Azure OpenAI GPT-4o Python Week 4: April 28th-30th Day/Time Topic Track 4/29, 01:00 PM UTC / 06:00 AM PT Irresponsible AI Agents Java 4/29, 04:00 PM UTC / 09:00 AM PT Securing AI agents on Azure Python Spanish / Español See all our Spanish sessions on the Spanish landing page. Consulta todas nuestras sesiones en español en la página de inicio en español. Portuguese / Português See our Portuguese sessions on the Portuguese landing page. Veja nossas sessões em português na página de entrada em português. Chinese / 简体字 See our Chinese sessions on the Chinese landing page. 请查看我们的中文课程在中文登录页面. Office Hours For additional help with your hacks, you can drop by Office Hours in our AI Discord channel. Here are the Office Hours scheduled so far: Day/Time Topic/Hosts Every Thursday, 12:30 PM PT Python + AI (English) Every Monday, 03:00 PM PT Python + AI (Spanish) Learning Resources Access resources here! Join TheSource EHub to explore top picks including trainings, livestreams, repositories, technical guides, blogs, downloads, certifications, and more, all updated monthly. The AI Agent section offers essential resources for creating AI Agents, while other sections provide insights into AI, development tools, and programming languages. You can also post questions in our discussions forum, or chat with attendees in the Discord channel.Bootcamp GitHub Copilot LATAM – gratuito y en español
GitHub Copilot Bootcamp LATAM es una serie de cuatro clases en vivo en español que enseñan consejos y prácticas recomendadas para usar GitHub Copilot. Aprende a crear soluciones rápidas, automatizar tareas repetitivas y colaborar eficazmente en proyectos. ¡REGÍSTRATE AHORA! ¿Por qué participar? GitHub Copilot no es solo una herramienta de sugerencia de código, sino un socio de programación que entiende tus necesidades y acelera tu trabajo. Al participar en el bootcamp, tendrás la oportunidad de: Dominar la creación de indicaciones efectivas. Aprender a desarrollar aplicaciones web utilizando IA. Descubrir cómo automatizar pruebas y generar documentación. Explorar las prácticas de colaboración y la implementación automatizada. Cronograma de clases Las sesiones serán a las 7pm CDMX, 5pm PT, 8pm ET y 2am CET (amigos en España, todas las sesiones se grabarán). 📅 4 de febrero de 2025 Ingeniería de avisos con GitHub Copilot Aprende cómo funciona Copilot y domina la IA responsable para aumentar tu productividad. 📅 6 de febrero de 2025 Construyendo una Aplicación Web de IA con Python y Flask Crea proyectos increíbles con la integración de IA y explora el uso de Copilot para simplificar las tareas. 📅 11 de febrero de 2025 Crea Pruebas Unitarias y Documentación con GitHub Copilot Automatice la documentación y desarrolle pruebas de manera eficiente aplicando conceptos directamente a proyectos del mundo real. 📅 13 de febrero de 2025 Colaboración e implementación con GitHub Copilot Aprenda a crear GitHub Actions, administrar solicitudes de incorporación de cambios y usar Copilot para Azure para la implementación. ¿Quién puede participar? Si eres desarrollador, estudiante o entusiasta de la tecnología, este bootcamp es para ti. Las clases están diseñadas para atender tanto a principiantes como a profesionales experimentados. ¿Cómo aplicar? ¡Asegura tu lugar ahora y comienza tu viaje para dominar GitHub Copilot! 👉 ¡REGÍSTRATE AHORA!
