Writing agent state
Write to agent's state from your application.
This example demonstrates writing to shared state in the CopilotKit Feature Viewer.
What is this?
You can easily write to your agent's state from your native application, allowing you to update the agent's working memory from your UI.
When should I use this?
You can use this when you want to provide user input or control to your agent's working memory. As your application state changes, you can update the agent state to reflect these changes.
Implementation
Run and connect your agent
You'll need to run your agent and connect it to CopilotKit before proceeding.
If you don't already have CopilotKit and your agent connected, choose one of the following options:
Define the Agent State
Create your LlamaIndex agent with a stateful structure using initial_state. Here's a complete example that tracks language:
from fastapi import FastAPI
from llama_index.llms.openai import OpenAI
from llama_index.protocols.ag_ui.router import get_ag_ui_workflow_router
# Initialize the LLM
llm = OpenAI(model="gpt-4o")
# Create the AG-UI workflow router
agentic_chat_router = get_ag_ui_workflow_router(
llm=llm,
system_prompt="""
You are a helpful assistant for tracking the language.
IMPORTANT:
- ALWAYS use the lower case for the language
- ALWAYS respond in the current language from the state
""",
initial_state={
"language": "english"
},
)
# Create FastAPI app
app = FastAPI(
title="LlamaIndex Agent",
description="A LlamaIndex agent integrated with CopilotKit",
version="1.0.0"
)
# Include the router
app.include_router(agentic_chat_router)
# Health check endpoint
@app.get("/health")
async def health_check():
return {"status": "healthy", "agent": "llamaindex"}
if __name__ == "__main__":
import uvicorn
uvicorn.run(app, host="localhost", port=8000)Use the useCoAgent Hook
With your agent connected and running all that is left is to call the useCoAgent hook, pass the agent's name, and
use the setState function to update the agent state.
"use client";
import { useCoAgent } from "@copilotkit/react-core";
// Define the agent state type, should match the actual state of your agent
type AgentState = {
language: "english" | "spanish";
}
// Example usage in a pseudo React component
function YourMainContent() {
const { state, setState } = useCoAgent<AgentState>({
name: "my_agent", // MUST match the agent name in CopilotRuntime
initialState: { language: "english" } // optionally provide an initial state
});
// ...
const toggleLanguage = () => {
setState({ language: state.language === "english" ? "spanish" : "english" });
};
// ...
return (
// style excluded for brevity
<div>
<h1>Your main content</h1>
<p>Language: {state.language}</p>
<button onClick={toggleLanguage}>Toggle Language</button>
</div>
);
}Important
The name parameter must exactly match the agent name you defined in your CopilotRuntime configuration (e.g., my_agent from the quickstart).
The setState function in useCoAgent will update the state and trigger a rerender when the state changes.
Give it a try!
You can now use the setState function to update the agent state and state to read it. Try toggling the language button
and talking to your agent. You'll see the language change to match the agent's state.
Advanced Usage
Re-run the agent with a hint about what's changed
The new agent state will be used next time the agent runs.
If you want to re-run it manually, use the run argument on the useCoAgent hook.
The agent will be re-run, and it will get not only the latest updated state, but also a hint that can depend on the data delta between the previous and the current state.
import { useCoAgent } from "@copilotkit/react-core";
import { TextMessage, MessageRole } from "@copilotkit/runtime-client-gql";
// ...
function YourMainContent() {
const { state, setState, run } = useCoAgent<AgentState>({
name: "my_agent", // MUST match the agent name in CopilotRuntime
initialState: { language: "english" } // optionally provide an initial state
});
// setup to be called when some event in the app occurs
const toggleLanguage = () => {
const newLanguage = state.language === "english" ? "spanish" : "english";
setState({ language: newLanguage });
// re-run the agent and provide a hint about what's changed
run(({ previousState, currentState }) => {
return new TextMessage({
role: MessageRole.User,
content: `the language has been updated to ${currentState.language}`,
});
});
};
return (
// ...
);
}
