Crate adk_core 

adk-core

Core traits and types for ADK agents, tools, sessions, and events.

Overview

This crate provides the foundational abstractions for the Agent Development Kit:

• Agent - The fundamental trait for all agents
• Tool / Toolset - For extending agents with custom capabilities
• Session / State - For managing conversation context
• Event - For streaming agent responses
• AdkError / Result - Unified error handling

Quick Start

use adk_core::{Agent, Tool, Event, Result};
use std::sync::Arc;

// All agents implement the Agent trait
// All tools implement the Tool trait
// Events are streamed as the agent executes

Core Traits

Agent

The Agent trait defines the interface for all agents:

#[async_trait]
pub trait Agent: Send + Sync {
    fn name(&self) -> &str;
    fn description(&self) -> Option<&str>;
    async fn run(&self, ctx: Arc<dyn InvocationContext>) -> Result<EventStream>;
}

Tool

The Tool trait defines custom capabilities:

#[async_trait]
pub trait Tool: Send + Sync {
    fn name(&self) -> &str;
    fn description(&self) -> &str;
    async fn execute(&self, ctx: Arc<dyn ToolContext>, args: Value) -> Result<Value>;
}

State Management

State uses typed prefixes for organization:

• user: - User preferences (persists across sessions)
• app: - Application state (application-wide)
• temp: - Temporary data (cleared each turn)

Re-exports

pub use agent::Agent;

pub use agent::EventStream;

pub use agent_loader::AgentLoader;

pub use agent_loader::MultiAgentLoader;

pub use agent_loader::SingleAgentLoader;

pub use callbacks::AfterAgentCallback;

pub use callbacks::AfterModelCallback;

pub use callbacks::AfterToolCallback;

pub use callbacks::BeforeAgentCallback;

pub use callbacks::BeforeModelCallback;

pub use callbacks::BeforeModelResult;

pub use callbacks::BeforeToolCallback;

pub use callbacks::GlobalInstructionProvider;

pub use callbacks::InstructionProvider;

pub use context::Artifacts;

pub use context::CallbackContext;

pub use context::IncludeContents;

pub use context::InvocationContext;

pub use context::Memory;

pub use context::MemoryEntry;

pub use context::ReadonlyContext;

pub use context::ReadonlyState;

pub use context::RunConfig;

pub use context::Session;

pub use context::State;

pub use context::StreamingMode;

pub use error::AdkError;

pub use error::Result;

pub use event::Event;

pub use event::EventActions;

pub use event::KEY_PREFIX_APP;

pub use event::KEY_PREFIX_TEMP;

pub use event::KEY_PREFIX_USER;

pub use instruction_template::inject_session_state;

pub use model::FinishReason;

pub use model::GenerateContentConfig;

pub use model::Llm;

pub use model::LlmRequest;

pub use model::LlmResponse;

pub use model::LlmResponseStream;

pub use model::UsageMetadata;

pub use tool::Tool;

pub use tool::ToolContext;

pub use tool::ToolPredicate;

pub use tool::Toolset;

pub use types::Content;

pub use types::Part;

Modules

agent

agent_loader

callbacks

context

error

event

instruction_template

model

tool

types