docs/content/docs/integrations/llamaindex/shared-state/state-inputs-outputs.mdx
Not all state properties are relevant for frontend-backend sharing. This guide shows how to ensure only the right portion of state is communicated back and forth.
Depending on your implementation, some properties are meant to be processed internally, while some others are the way for the UI to communicate user input. In addition, some state properties contain a lot of information. Syncing them back and forth between the agent and UI can be costly, while it might not have any practical benefit.
```python title="agent.py"
# Full state structure for the agent
initial_state = {
"question": "", # Input from user
"answer": "", # Output to user
"resources": [] # Internal use only
}
```
Here's a complete example showing how to structure your agent with these considerations:
```python title="agent.py"
from typing import Annotated, List
from fastapi import FastAPI
from llama_index.llms.openai import OpenAI
from llama_index.core.workflow import Context
from llama_index.protocols.ag_ui.router import get_ag_ui_workflow_router
from llama_index.protocols.ag_ui.events import StateSnapshotWorkflowEvent
async def answerQuestion(
ctx: Context,
answer: Annotated[str, "The answer to store in state."]
) -> str:
"""Stores the answer to the user's question in shared state.
Args:
ctx: The workflow context for state management.
answer: The answer to store in state.
Returns:
str: A message indicating the answer was stored.
"""
async with ctx.store.edit_state() as global_state:
state = global_state.get("state", {})
if state is None:
state = {}
state["answer"] = answer
# Emit state update to frontend
ctx.write_event_to_stream(
StateSnapshotWorkflowEvent(snapshot=state)
)
global_state["state"] = state
return f"Answer stored: {answer}"
async def addResource(
ctx: Context,
resource: Annotated[str, "The resource URL or reference to add."]
) -> str:
"""Adds a resource to the internal resources list in shared state.
Args:
ctx: The workflow context for state management.
resource: The resource URL or reference to add.
Returns:
str: A message indicating the resource was added.
"""
async with ctx.store.edit_state() as global_state:
state = global_state.get("state", {})
if state is None:
state = {}
resources = state.get("resources", [])
resources.append(resource)
state["resources"] = resources
global_state["state"] = state
return f"Resource added: {resource}"
# Initialize the LLM
llm = OpenAI(model="gpt-5.4")
# Create the AG-UI workflow router
agentic_chat_router = get_ag_ui_workflow_router(
llm=llm,
system_prompt="""
You are a helpful assistant. When the user asks a question:
1. Think through your answer
2. Optionally use addResource to track any sources you reference
3. Use answerQuestion to provide your final answer - this stores it in state for the user to see
Always use the answerQuestion tool to provide your response so it appears in the UI.
""",
backend_tools=[answerQuestion, addResource],
initial_state={
"question": "", # Input: received from frontend
"answer": "", # Output: sent to frontend
"resources": [] # Internal: tracking resources
},
)
# 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)
```
```tsx title="ui/app/page.tsx"
"use client";
import { useState } from "react";
import { useAgent, useCopilotKit } from "@copilotkit/react-core/v2";
// Define the agent state type, should match the actual state of your agent
type AgentState = {
question: string;
answer: string;
}
/* Example usage in a pseudo React component */
function YourMainContent() { // [!code highlight]
const [inputQuestion, setInputQuestion] = useState("What's the capital of France?");
const [isLoading, setIsLoading] = useState(false);
const { agent } = useAgent({
agentId: "my_agent",
});
const { copilotkit } = useCopilotKit();
const askQuestion = async (newQuestion: string) => {
setIsLoading(true);
// Update the state with the new question
agent.setState({ ...agent.state, question: newQuestion, answer: "" });
try {
// Add a message and trigger the agent to run
agent.addMessage({
id: crypto.randomUUID(),
role: "user",
content: newQuestion,
});
await copilotkit.runAgent({ agent });
} catch (error) {
console.error("Error running agent:", error);
} finally {
setIsLoading(false);
}
};
return (
<div style={{ padding: "2rem", fontFamily: "system-ui, sans-serif" }}>
<h1>Q&A Assistant</h1>
<div style={{ marginBottom: "1rem" }}>
<input
type="text"
value={inputQuestion}
onChange={(e) => setInputQuestion(e.target.value)}
placeholder="Enter your question..."
style={{
padding: "0.5rem",
width: "300px",
marginRight: "0.5rem",
borderRadius: "4px",
border: "1px solid #ccc"
}}
/>
<button
onClick={() => askQuestion(inputQuestion)}
disabled={isLoading || !inputQuestion.trim()}
style={{
padding: "0.5rem 1rem",
borderRadius: "4px",
border: "none",
backgroundColor: isLoading ? "#ccc" : "#0070f3",
color: "white",
cursor: isLoading ? "not-allowed" : "pointer"
}}
>
{isLoading ? "Thinking..." : "Ask Question"}
</button>
</div>
<div style={{ marginTop: "1.5rem" }}>
<p><strong>Question:</strong> {agent.state?.question || "(none yet)"}</p>
<p><strong>Answer:</strong> {agent.state?.answer || (isLoading ? "Thinking..." : "Waiting for question...")}</p>
</div>
</div>
);
}
```
<Callout type="warn" title="Important">
The `name` parameter must exactly match the agent name you defined in your CopilotRuntime configuration (e.g., `my_agent` from the quickstart).
</Callout>