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?#
This guide shows you how to write to your agent's state from your application.
When should I use this?#
You can use this when you want to provide the user with feedback about what your agent is doing, specifically when your agent is calling tools. CopilotKit allows you to fully customize how these tools are rendered in the chat.
Implementation#
Run and connect your agent#
You'll need to run your agent and connect it to CopilotKit before proceeding. If you haven't done so already, you can follow the instructions in the Getting Started guide.
If you don't already have an agent, you can use the coagent starter as a starting point as this guide uses it as a starting point.
Define the Agent State#
LangGraph is stateful. As you transition between nodes, that state is updated and passed to the next node. For this example, let's assume that our agent state looks something like this.
Use the useAgent hook to read and write state#
useAgent gives you access to the agent, including its state. You can update state by calling agent.setState.
import { useAgent } from "@copilotkit/react-core/v2"; // [!code highlight]
// Example usage in a pseudo React component
function YourMainContent() {
// [!code highlight:3]
const { agent } = useAgent({
agentId: "sample_agent",
});
const language = (agent.state.language as string) ?? "english";
// ...
const toggleLanguage = () => {
agent.setState({ language: language === "english" ? "spanish" : "english" }); // [!code highlight]
};
// ...
return (
// style excluded for brevity
<div>
<h1>Your main content</h1>
{/* [!code highlight:1] */}
<p>Language: {language}</p>
<button onClick={toggleLanguage}>Toggle Language</button>
</div>
);
}
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.
This video shows the result of npx copilotkit@latest init with the implementation section applied to it!
Advanced Usage#
Re-run the agent with updated state#
The new agent state will be used next time the agent runs.
If you want to re-run it manually, use agent.runAgent after updating state.
import { useAgent } from "@copilotkit/react-core/v2"; // [!code highlight]
// ...
function YourMainContent() {
const { agent } = useAgent({
agentId: "sample_agent",
});
const language = (agent.state.language as string) ?? "english";
// setup to be called when some event in the app occurs
const toggleLanguage = () => {
const newLanguage = language === "english" ? "spanish" : "english";
agent.setState({ language: newLanguage });
// [!code highlight:2]
// re-run the agent with updated state
agent.runAgent();
};
return (
// ...
);
}
Intermediately Stream and Render Agent State#
By default, the LangGraph agent state will only update between LangGraph node transitions -- which means state updates will be discontinuous and delayed.
You likely want to render the agent state as it updates continuously.