google--adk-python/contributing/samples/core/app

Application Configuration (App)

Overview

This sample demonstrates how to configure an App in ADK. An App serves as the top-level container for an agentic system, wrapping a root agent or workflow and providing application-wide configurations such as plugins, event compaction, and context caching.

Sample Inputs

• Hello, who are you?

  The application executes greeter_agent. The CountInvocationPlugin logs the agent and LLM run counts to the console.

• Can you help me plan a trip?

  As the conversation continues, event compaction automatically summarizes past turns every 2 invocations, while context caching optimizes token usage.

Graph

graph TD
    User[User Input] --> AppContainer[App: app]
    subgraph AppContainer [App Container]
        Plugins[Plugins: CountInvocation, SaveFilesAsArtifacts] --> GreeterAgent[root_agent: greeter_agent]
        GreeterAgent --> Configs[Configs: EventCompaction, ContextCache]
    end
    AppContainer --> Response[User Response]

How To

Wrapping an Agent in an App

To configure application-level behaviors, instantiate an App object and pass your root agent to the root_agent parameter:

from google.adk import Agent
from google.adk.apps.app import App

root_agent = Agent(
    name="greeter_agent",
    instruction="You are a friendly assistant.",
)

app = App(
    name="app",
    root_agent=root_agent,
)

Configuring Application Plugins

Plugins provide cross-cutting capabilities (such as telemetry, custom logging, or artifact saving) across the entire application. Pass a list of plugin instances to plugins:

from google.adk.plugins.save_files_as_artifacts_plugin import SaveFilesAsArtifactsPlugin

app = App(
    name="app",
    root_agent=root_agent,
    plugins=[
        CountInvocationPlugin(),
        SaveFilesAsArtifactsPlugin(),
    ],
)

Configuring Event Compaction and Caching

The App container is also where you define long-term session behavior and optimization strategies:

• events_compaction_config: Manages token usage by periodically summarizing older turns in a session.
• context_cache_config: Enables prompt caching across invocations to reduce latency and cost.

from google.adk.apps.app import EventsCompactionConfig
from google.adk.agents.context_cache_config import ContextCacheConfig

app = App(
    name="app",
    root_agent=root_agent,
    events_compaction_config=EventsCompactionConfig(
        compaction_interval=2,
        overlap_size=1,
    ),
    context_cache_config=ContextCacheConfig(
        cache_intervals=10,
        ttl_seconds=1800,
        min_tokens=1000,
    ),
)