CopilotKit

Authentication

Pass user auth context from your frontend to the agent so it can scope tools, data, and decisions to the signed-in user.

"use client";// Auth demo — framework-native request authentication via the V2 runtime's// `onRequest` hook. The runtime route (/api/copilotkit-auth) rejects any// request whose `Authorization: Bearer <demo-token>` header is missing or// wrong.//// UX shape: the demo defaults to UNAUTHENTICATED on first paint so visitors// land on a clear sign-in card. We don't render `<CopilotKit>` until the user// has signed in at least once — that sidesteps the transport 401 that would// otherwise crash `<CopilotChat>` during its initial `/info` handshake.// After the user signs in once, `<CopilotKit>` stays mounted across the// sign-out → sign-in cycle so the post-sign-out state can actually// demonstrate the runtime rejecting unauthenticated requests in the chat// surface (the whole point of the demo).//// Error surfacing: the post-sign-out 401 is captured via the AGENT-SCOPED// `<CopilotChat onError>` channel, NOT the provider-level `<CopilotKit// onError>` alone. Agent-run errors (`agent_run_failed`) are reliably// delivered to the chat-scoped subscription, whereas the provider-level// handler does not fire for them in this flow — so a demo that relies only// on `<CopilotKit onError>` never renders the rejection banner. We register// the same handler on BOTH channels: `<CopilotKit onError>` covers any// provider-level errors (e.g. the initial `/info` handshake) and// `<CopilotChat onError>` covers agent-run rejections, which is what the// sign-out path produces.import { useCallback, useEffect, useMemo, useState } from "react";import { CopilotKit, CopilotChat } from "@copilotkit/react-core/v2";import type { CopilotKitCoreErrorCode } from "@copilotkit/react-core/v2";import { AuthBanner } from "./auth-banner";import { SignInCard } from "./sign-in-card";import { useDemoAuth } from "./use-demo-auth";import { DEMO_TOKEN } from "./demo-token";interface AuthDemoErrorState {  message: string;  code: CopilotKitCoreErrorCode | string;}interface AuthErrorEvent {  error?: { message?: string } | null;  code: CopilotKitCoreErrorCode;}export default function AuthDemoPage() {  const {    isAuthenticated,    authorizationHeader,    hasEverSignedIn,    signIn,    signOut,  } = useDemoAuth();  const headers = useMemo<Record<string, string>>(    () => (authorizationHeader ? { Authorization: authorizationHeader } : {}),    [authorizationHeader],  );  const [authError, setAuthError] = useState<AuthDemoErrorState | null>(null);  // Shared error handler wired to BOTH the provider-level and chat-level  // `onError` channels (see the file header for why both are needed).  const handleAuthError = useCallback((event: AuthErrorEvent) => {    setAuthError({      message:        (event.error?.message && event.error.message.trim()) ||        (event.code          ? `Request rejected (${event.code})`          : "The request was rejected."),      code: event.code,    });  }, []);  // Clear stale errors as soon as the user re-authenticates. This is the  // ONLY thing that gates the amber error surface on auth state — the render  // condition below keys off `authError` alone. Coupling the render to a  // second `!isAuthenticated` slice (the obvious-but-wrong guard) created a  // post-sign-out race: the rejection's `onError` fires and calls  // `setAuthError`, but if that commit landed in a render where the auth  // state hadn't yet settled to false, `authError && !isAuthenticated`  // evaluated false and the banner never appeared. Driving the surface off  // `authError` and clearing it here on re-auth removes the cross-slice  // ordering dependency: a rejection always renders, and signing back in  // always wipes it.  useEffect(() => {    if (isAuthenticated) setAuthError(null);  }, [isAuthenticated]);  if (!hasEverSignedIn) {    return (      <div className="flex h-screen flex-col">        <SignInCard onSignIn={signIn} />      </div>    );  }  return (    // `useSingleEndpoint={false}` opts into the V2 multi-endpoint protocol    // (separate /info, /agents/<id>/run, etc.), which is what this demo's    // runtime route is wired up for.    <CopilotKit      runtimeUrl="/api/copilotkit-auth"      agent="auth-demo"      headers={headers}      useSingleEndpoint={false}      onError={handleAuthError}    >      <div className="flex h-screen flex-col gap-3 p-6">        <AuthBanner          authenticated={isAuthenticated}          onSignOut={signOut}          onSignIn={() => signIn(DEMO_TOKEN)}        />        <header>          <h1 className="text-lg font-semibold">Authentication</h1>        </header>        {authError && (          <div            data-testid="auth-demo-error"            className="rounded-md border border-amber-300 bg-amber-50 px-3 py-2 text-sm text-amber-900"          >            <strong className="font-semibold">              Runtime rejected the request:            </strong>{" "}            <span data-testid="auth-demo-error-message">              {authError.message}            </span>{" "}            <code className="ml-1 rounded bg-amber-100 px-1 py-0.5 font-mono text-xs">              {authError.code}            </code>          </div>        )}        <div className="flex-1 overflow-hidden rounded-md border border-neutral-200">          <CopilotChat            agentId="auth-demo"            className="h-full"            onError={handleAuthError}          />        </div>      </div>    </CopilotKit>  );}

You have a chat surface or a hook driving an agent and you want every agent run to know who the request came from. By the end of this guide, your frontend will forward a token, the runtime will pass it through, and your agent code will read the resulting user info on every turn.

When to use this#

  • Multi-tenant apps where the agent reads or writes per-user data.
  • Tool gating where some tools should only run for authorised users.
  • Audit and billing where every run needs an identity to attribute it to.
  • Session-aware UX where the agent's behaviour depends on the user's role or permissions.

If you don't need any of those, skip auth entirely. The agent runs anonymously and the frontend never has to care about tokens.

Frontend#

Pass your token via the headers prop. CopilotKit attaches it to every runtime request, and the runtime forwards the Authorization header on to your agent — whether that's a LangGraph deployment or a self-hosted AG-UI endpoint.

frontend/src/app/page.tsx
import { CopilotKit } from "@copilotkit/react-core/v2";

<CopilotKit
  runtimeUrl="/api/copilotkit"
  headers={{
    Authorization: `Bearer ${userToken}`,
  }}
>
  <YourApp />
</CopilotKit>

`properties` is not an auth channel

Older versions of this guide passed the token as properties={{ authorization: userToken }}. The runtime delivers properties to the agent as AG-UI forwardedProps — run payload data, not a request header — so nothing turns them into a Bearer credential. Use headers for auth. Headers the server configured on the agent itself still win on collision, so a service-to-service token can't be overridden from the browser.

Backend#

LangGraph supports two deployment modes. The frontend code above is the same in both, but the backend wiring differs in where the resolved user identity lands. Pick the tab that matches where your agent runs.

On LangGraph Platform (and on langgraph dev), authentication is a managed service. You declare an @auth.authenticate handler, and the server runs it on every request before the graph starts. The forwarded Authorization header arrives as the handler's authorization argument, and the handler's return value becomes available to every node in the run.

backend/auth.py
from langgraph_sdk import Auth

auth = Auth()

@auth.authenticate
async def authenticate(authorization: str | None):
    if not authorization or not authorization.startswith("Bearer "):
        raise Auth.exceptions.HTTPException(status_code=401, detail="Unauthorized")

    token = authorization.replace("Bearer ", "")
    user_info = validate_your_token(token)  # your validation logic

    return {
        "identity": user_info["user_id"],
        "role": user_info.get("role"),
        "permissions": user_info.get("permissions", []),
    }

The return value of the handler shows up in every node's config["configurable"]["langgraph_auth_user"]. From there, scoping tool access or filtering data is straightforward:

backend/agent.py
from langchain_core.runnables import RunnableConfig

async def my_agent_node(state: AgentState, config: RunnableConfig):
    user_info = config["configurable"]["langgraph_auth_user"]
    user_id = user_info["identity"]
    user_role = user_info.get("role")
    # agent logic with user context
    return state

For full handler details, see the LangGraph Platform Authentication documentation.

When you self-host the agent behind FastAPI, there's no managed auth handler to plug into — validation is your job, and the natural place for it is the endpoint that serves the AG-UI stream. add_langgraph_fastapi_endpoint mounts that endpoint for you, but it takes one pre-built agent and gives you no per-request hook, so replace it with the equivalent route of your own: a FastAPI dependency verifies the Authorization header the runtime forwarded, and the resolved user is baked into a per-request agent's config.

backend/main.py
from typing import Optional

from ag_ui.core.types import RunAgentInput
from ag_ui.encoder import EventEncoder
from copilotkit import LangGraphAGUIAgent
from fastapi import Depends, FastAPI, Header, HTTPException, Request
from fastapi.responses import StreamingResponse

from src.agent import graph

app = FastAPI()

def current_user(authorization: Optional[str] = Header(default=None)) -> dict:
    if not authorization or not authorization.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="Missing bearer token")
    return validate_your_token(authorization.removeprefix("Bearer ").strip())  # your validation

@app.post("/")
async def run_agent(
    input_data: RunAgentInput,
    request: Request,
    user: dict = Depends(current_user),
):
    encoder = EventEncoder(accept=request.headers.get("accept"))

    # One agent per request: the verified identity rides on this run only, and
    # each request gets its own isolated streaming state.
    agent = LangGraphAGUIAgent(
        name="sample_agent",
        graph=graph,
        config={"configurable": {"auth_user": user}},
    )

    async def event_generator():
        async for event in agent.run(input_data):
            yield encoder.encode(event)

    return StreamingResponse(event_generator(), media_type=encoder.get_content_type())

Unauthenticated requests never reach the graph — they get a 401 from the dependency. Authenticated ones arrive with an already-verified user on the config, so nodes read identity instead of re-validating a raw token:

backend/src/agent.py
from langchain_core.runnables import RunnableConfig

async def my_agent_node(state: AgentState, config: RunnableConfig):
    user = config["configurable"]["auth_user"]
    user_id = user["user_id"]
    user_role = user.get("role")
    # agent logic with user context
    return state

If you only need the 401 gate

When nodes don't need the identity — you just want unauthenticated traffic rejected — keep add_langgraph_fastapi_endpoint and hang the dependency off the app: FastAPI(dependencies=[Depends(current_user)]). The gate applies, but nothing lands on the run config, so config["configurable"] stays empty of user context.

`CopilotKitRemoteEndpoint` no longer works here

Guides written for CopilotKit v1 wrapped the graph in CopilotKitRemoteEndpoint(agents=lambda context: [...]). That path is retired: copilotkit no longer exports LangGraphAgent (ImportError), and the current LangGraphAGUIAgent exposes run() rather than the execute() that CopilotKitRemoteEndpoint calls — giving AgentExecutionException: 'LangGraphAGUIAgent' object has no attribute 'execute'. Use the endpoint above instead.

Tool gating#

The most common reason to wire auth is so individual tools can decline to run. Read the resolved user inside the tool's handler and bail if the role doesn't match:

def delete_record(record_id: str, *, user: User):
    if "admin" not in user.permissions:
        raise PermissionError("admin role required")
    # do the delete

This composes with Human in the loop: gate on auth first, surface a confirmation card next, execute last.

Security checklist#

  • Always validate the token on the backend. Never trust the frontend's claim.
  • Scope every read and write to the resolved user. Auth context only matters if you actually use it to filter data.
  • Don't log raw tokens. Log the resolved user id (or anonymous) instead.
  • Use HTTPS in production. The Bearer token is sensitive.
  • Refresh strategy. Your frontend is responsible for rotating expired tokens before they reach the agent. CopilotKit doesn't refresh on your behalf.

On this page

When to use thisFrontendBackendTool gatingSecurity checklist