Model Context Protocol (MCP)

The ADK provides first-class support for the Model Context Protocol (MCP), enabling your agents to dynamically discover and consume tools provided by external MCP servers. This allows your agent to safely interact with a vast ecosystem of third-party APIs and local resources.

Core Components

• McpToolset: Connects to an MCP server, discovers its available tools, and makes them available to an agent. It manages the lifecycle of the connection.
• McpSessionManager: Manages the underlying client sessions (e.g., Stdio or HTTP) and handles protocol-level communication.
• McpTool: A dynamically generated wrapper for an individual MCP tool, exposing it to the LLM identically to any other IBaseTool.

Connecting to an MCP Server

The ADK supports connecting to MCP servers via standard input/output (stdio) or over HTTP/SSE.

Stdio Connections (Local Processes)

Connecting to a local MCP server via stdio is ideal for utilities running on the same machine, such as npx packages or Python tools via uvx.

using GoogleAdk.Tools.Mcp;
using GoogleAdk.Core.Agents;

// 1. Configure the connection parameters for the MCP server
var stdioParams = new StdioConnectionParams
{
    Command = "npx",
    Arguments = ["-y", "@modelcontextprotocol/server-everything"],
    TimeoutMs = 30_000 // Optional: Set a startup/request timeout
};

// 2. Initialize the toolset
// Note: It's important to dispose of the toolset when shutting down 
// your application to ensure the external process exits cleanly.
var toolset = new McpToolset(stdioParams, prefix: "mcp");

// 3. Attach the toolset to your agent
var agent = new LlmAgent(new LlmAgentConfig
{
    Name = "mcp_agent",
    Model = "gemini-2.5-flash",
    Instruction = "You have access to MCP tools. Use them to assist the user.",
    // The toolset will automatically discover all tools provided by the server
    Toolsets = [toolset] 
});

// To clean up later:
// await toolset.DisposeAsync();

Using Python-based MCP Servers (e.g., uvx):

var blenderParams = new StdioConnectionParams
{
    Command = "uvx",
    Arguments = ["-q", "blender-mcp"],
    TimeoutMs = 60_000
};
var blenderToolset = new McpToolset(blenderParams);

HTTP/SSE Connections (Remote Servers)

You can connect to remote MCP servers over HTTP using Server-Sent Events (SSE). This is useful when the MCP server is hosted externally or behind a load balancer.

using GoogleAdk.Tools.Mcp;
using GoogleAdk.Core.Agents;

// 1. Configure the connection parameters for the remote server
var httpParams = new HttpConnectionParams
{
    Url = "http://localhost:8788/mcp",
    // You can also provide custom HTTP headers if the server requires them
    Headers = new Dictionary<string, string>
    {
        { "Authorization", "Bearer my-secret-token" }
    }
};

// 2. Initialize the toolset
var toolset = new McpToolset(httpParams);

// 3. Attach the toolset to your agent
var agent = new LlmAgent(new LlmAgentConfig
{
    Name = "mcp_http_agent",
    Model = "gemini-2.5-flash",
    Toolsets = [toolset]
});

Prefixing Tool Names

MCP servers often expose generic tool names like search or execute. To prevent naming collisions when using multiple toolsets or built-in tools, you can specify a prefix.

// Tools will be exposed as 'github_search', 'github_execute', etc.
var toolset = new McpToolset(stdioParams, prefix: "github");

Security and Authentication

• The Headers property in HttpConnectionParams allows you to pass authentication tokens to remote servers.
• Further connection hardening and granular tool filtering capabilities will be added in future releases.