Crate adk_tool 

adk-tool

Tool system for ADK agents (FunctionTool, MCP, Google Search, AgentTool).

Overview

This crate provides the tool infrastructure for ADK agents:

• FunctionTool - Create tools from async Rust functions
• AgentTool - Use agents as callable tools for composition
• GoogleSearchTool - Web search via Gemini’s grounding
• McpToolset - Model Context Protocol integration
• BasicToolset - Group multiple tools together
• ExitLoopTool - Control flow for loop agents
• LoadArtifactsTool - Inject binary artifacts into context

Quick Start

use adk_tool::FunctionTool;
use adk_core::{ToolContext, Result};
use serde_json::{json, Value};
use std::sync::Arc;

async fn get_weather(ctx: Arc<dyn ToolContext>, args: Value) -> Result<Value> {
    let city = args["city"].as_str().unwrap_or("Unknown");
    Ok(json!({
        "city": city,
        "temperature": 72,
        "condition": "sunny"
    }))
}

let tool = FunctionTool::new(
    "get_weather",
    "Get current weather for a city",
    get_weather,
);

MCP Integration

Connect to MCP servers for external tools:

use adk_tool::McpToolset;
use rmcp::{ServiceExt, transport::TokioChildProcess};

let client = ().serve(TokioChildProcess::new(
    Command::new("npx")
        .arg("-y")
        .arg("@modelcontextprotocol/server-filesystem")
        .arg("/path/to/files")
)?).await?;

let toolset = McpToolset::new(client);

Re-exports

pub use builtin::ExitLoopTool;

pub use builtin::GoogleSearchTool;

pub use builtin::LoadArtifactsTool;

pub use mcp::McpAuth;

pub use mcp::McpHttpClientBuilder;

pub use mcp::McpTaskConfig;

pub use mcp::McpToolset;

pub use mcp::OAuth2Config;

pub use toolset::BasicToolset;

pub use toolset::FilteredToolset;

pub use toolset::MergedToolset;

pub use toolset::PrefixedToolset;

pub use toolset::string_predicate;

Modules

builtin

mcp

toolset

Structs

AgentTool

AgentTool wraps an Agent to make it callable as a Tool.

AgentToolConfig

Configuration options for AgentTool behavior.

FunctionTool

Enums

AdkError

Unified error type for all ADK operations.

Traits

Tool

ToolContext

Toolset

Type Aliases

Result

Convenience alias used throughout ADK crates.

Attribute Macros

tool

Attribute macro that generates a Tool implementation from an async function.