Agent Development Kit (ADK) for .NET

The Agent Development Kit (ADK) is a code-first toolkit for building AI agents in .NET. It lets you define agent behavior, orchestration, and tools directly in C#, integrating closely with Google Cloud services.

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⚠️ EXPERIMENTAL - This project is in active development. The API is subject to change.

Documentation

For guides, API references, and feature details, see the documentation.

Installation

dotnet add package GoogleAdk --prerelease

Features

Agents & Models

• LLM agents: LlmAgent with tool use, instructions, streaming, and structured output.
• Models: Gemini and local providers such as Ollama.
• Orchestration: SequentialAgent, ParallelAgent, and LoopAgent for multi-step workflows.
• Planning: ReAct-style planners for goal-oriented task breakdown.
• Caching: Gemini-backed implicit prompt and context caching.

Tools & Integrations

• Function tools: Turn C# methods into agent tools with the [FunctionTool] attribute.
• MCP: Model Context Protocol support for connecting to external MCP servers and discovering tools at runtime.
• OpenAPI: Generate tools from OpenAPI specs with OpenAPIToolset.
• Agent skills: Folder-based skills (SKILL.md, references/, assets/, scripts/) via SkillToolset and SkillLoader.LoadFromDirectory.
• Built-in tools: Google Search, BigQuery, Cloud Spanner, Vertex AI Search, RAG Engine, Computer Use, and code execution.
• Text-to-speech: Audio generation from compatible models such as gemini-2.5-flash-preview-tts.

Protocols & Connectivity

• A2A: Agent-to-agent communication over the A2A protocol, with client and server support.
• Plugins & telemetry: Lifecycle hooks, streaming events, and OpenTelemetry-style tracing.

State, Memory & Evaluation

• Session state: Dynamic instructions with placeholder injection.
• Memory: Built-in memory services and persistence, including EF Core storage.
• Evaluation & optimization: Eval sets, inference runs, LLM-as-judge scoring, and prompt tuning.

Runners & UI

• Console runner: Run agents interactively from the command line.
• Web server & UI: Embedded development server with REST/WebSocket APIs, Swagger, and a built-in UI for testing and debugging agents.

Example Usage

// Load env variables like GOOGLE_API_KEY
AdkEnv.Load();

var rootAgent = new LlmAgent(new()
{
    Name = "weather_assistant",
    Description = "An assistant that provides weather data.",
    Model = "gemini-2.5-flash",
    Instruction = "You are a helpful assistant. If the user asks about weather, use the GetWeatherData tool to provide the forecast.",
    Tools = [GetWeatherDataTool]
});

// Creates a webserver that can launch the ADK web UI and other endpoints 
await AdkServer.RunAsync(rootAgent);

// await ConsoleRunner.RunAsync(rootAgent); // For CLI usage

/// <summary>
/// Fetches the current weather data for a given location.
/// </summary>
/// <param name="location">The location to get the weather for (e.g., 'New York')</param>
/// <returns>A WeatherData object containing the location and forecast</returns>
[FunctionTool]
static WeatherData? GetWeatherData(string location)
{
    return new WeatherData(location, "Sunny with a chance of rainbows");
}

public record WeatherData(string Location, string Forecast);

Development UI

A built-in development UI to test, evaluate, and debug your agents.

Samples

Runnable samples cover MCP, A2A, orchestration, skills, evaluation, plugins, audio, and more. See samples/README.md for the full index.

cd samples/GoogleAdk.Samples.GoogleSearch
cp .env.example .env          # then edit .env and set GOOGLE_API_KEY
dotnet run

Building from Source

Prerequisites: .NET SDK 10.0+.

git clone https://github.com/sps014/GoogleAdk-cs.git
cd GoogleAdk-cs
dotnet build GoogleAdk.slnx
dotnet test GoogleAdk.slnx

Package versions are managed centrally in Directory.Packages.props, and shared build settings are in Directory.Build.props.

Contributing

See our guidelines:

• General contribution guideline and flow
• Code Contributing Guidelines

License

Google’s Agent Development Kit (ADK) is a copyrighted product of Google LLC. Google retains applicable rights in that product and in the ADK and Google trademarks.

This repository is a .NET port: an open-source implementation aligned with ADK-style APIs and patterns. It is not Google’s first-party release of ADK for .NET. Copyright in this port belongs to its contributors, who license the code under the Apache License, Version 2.0. See LICENSE.md for full terms.

Use, reproduction, and distribution of this repository are governed by the Apache License, Version 2.0. It does not transfer ownership of Google’s ADK, Google’s trademarks, or third-party materials.