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Routing

This guide explains how requests are routed to agents, how naming works, and patterns for organizing your agents.

How routing works

When a request comes in, routeAgentRequest() examines the URL and routes it to the appropriate agent instance:

https://your-worker.dev/agents/{agent-name}/{instance-name}
                               └────┬────┘   └─────┬─────┘
                               Class name     Unique instance ID
                              (kebab-case)

Example URLs:

URLAgent ClassInstance
/agents/counter/user-123Counteruser-123
/agents/chat-room/lobbyChatRoomlobby
/agents/my-agent/defaultMyAgentdefault

Name resolution

Agent class names are automatically converted to kebab-case for URLs:

Class NameURL Path
Counter/agents/counter/...
MyAgent/agents/my-agent/...
ChatRoom/agents/chat-room/...
AIAssistant/agents/ai-assistant/...

The router matches both the original name and kebab-case version, so you can use either:

  • useAgent({ agent: "Counter" }) → /agents/counter/...
  • useAgent({ agent: "counter" }) → /agents/counter/...

Using routeAgentRequest()

The routeAgentRequest() function is the main entry point for agent routing:

JavaScript
import { routeAgentRequest } from "agents";


export default {
  async fetch(request, env, ctx) {
    // Route to agents - returns Response or undefined
    const agentResponse = await routeAgentRequest(request, env);


    if (agentResponse) {
      return agentResponse;
    }


    // No agent matched - handle other routes
    return new Response("Not found", { status: 404 });
  },
};

Instance naming patterns

The instance name (the last part of the URL) determines which agent instance handles the request. Each unique name gets its own isolated agent with its own state.

Per-user agents

Each user gets their own agent instance:

JavaScript
// Client
const agent = useAgent({
  agent: "UserProfile",
  name: `user-${userId}`, // e.g., "user-abc123"
});
 
/agents/user-profile/user-abc123 → User abc123's agent
/agents/user-profile/user-xyz789 → User xyz789's agent (separate instance)

Shared rooms

Multiple users share the same agent instance:

JavaScript
// Client
const agent = useAgent({
  agent: "ChatRoom",
  name: roomId, // e.g., "general" or "room-42"
});
 
/agents/chat-room/general → All users in "general" share this agent

Global singleton

A single instance for the entire application:

JavaScript
// Client
const agent = useAgent({
  agent: "AppConfig",
  name: "default", // Or any consistent name
});

Dynamic naming

Generate instance names based on context:

JavaScript
// Per-session
const agent = useAgent({
  agent: "Session",
  name: sessionId,
});


// Per-document
const agent = useAgent({
  agent: "Document",
  name: `doc-${documentId}`,
});


// Per-game
const agent = useAgent({
  agent: "Game",
  name: `game-${gameId}-${Date.now()}`,
});

Custom URL routing

For advanced use cases where you need control over the URL structure, you can bypass the default /agents/{agent}/{name} pattern.

Using basePath (client-side)

The basePath option lets clients connect to any URL path:

JavaScript
// Client connects to /user instead of /agents/user-agent/...
const agent = useAgent({
  agent: "UserAgent", // Required but ignored when basePath is set
  basePath: "user", // → connects to /user
});

This is useful when:

  • You want clean URLs without the /agents/ prefix
  • The instance name is determined server-side (for example, from auth/session)
  • You are integrating with an existing URL structure

Server-side instance selection

When using basePath, the server must handle routing. Use getAgentByName() to get the agent instance, then forward the request with fetch():

JavaScript
export default {
  async fetch(request, env) {
    const url = new URL(request.url);


    // Custom routing - server determines instance from session
    if (url.pathname === "/user") {
      const session = await getSession(request);
      const agent = await getAgentByName(env.UserAgent, session.userId);
      return agent.fetch(request); // Forward request directly to agent
    }


    // Default routing for standard /agents/... paths
    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  },
};

Custom path with dynamic instance

Route different paths to different instances:

JavaScript
// Route /chat/{room} to ChatRoom agent
if (url.pathname.startsWith("/chat/")) {
  const roomId = url.pathname.replace("/chat/", "");
  const agent = await getAgentByName(env.ChatRoom, roomId);
  return agent.fetch(request);
}


// Route /doc/{id} to Document agent
if (url.pathname.startsWith("/doc/")) {
  const docId = url.pathname.replace("/doc/", "");
  const agent = await getAgentByName(env.Document, docId);
  return agent.fetch(request);
}

Receiving the instance identity (client-side)

When using basePath, the client does not know which instance it connected to until the server returns this information. The agent automatically sends its identity on connection:

JavaScript
const agent = useAgent({
  agent: "UserAgent",
  basePath: "user",
  onIdentity: (name, agentType) => {
    console.log(`Connected to ${agentType} instance: ${name}`);
    // e.g., "Connected to user-agent instance: user-123"
  },
});


// Reactive state - re-renders when identity is received
return (
  <div>
    {agent.identified ? `Connected to: ${agent.name}` : "Connecting..."}
  </div>
);

For AgentClient:

JavaScript
const agent = new AgentClient({
  agent: "UserAgent",
  basePath: "user",
  host: "example.com",
  onIdentity: (name, agentType) => {
    // Update UI with actual instance name
    setInstanceName(name);
  },
});


// Wait for identity before proceeding
await agent.ready;
console.log(agent.name); // Now has the server-determined name

Handling identity changes on reconnect

If the identity changes on reconnect (for example, session expired and user logs in as someone else), you can handle it with onIdentityChange:

JavaScript
const agent = useAgent({
  agent: "UserAgent",
  basePath: "user",
  onIdentityChange: (oldName, newName, oldAgent, newAgent) => {
    console.log(`Session changed: ${oldName} → ${newName}`);
    // Refresh state, show notification, etc.
  },
});

If onIdentityChange is not provided and identity changes, a warning is logged to help catch unexpected session changes.

Disabling identity for security

If your instance names contain sensitive data (session IDs, internal user IDs), you can disable identity sending:

JavaScript
class SecureAgent extends Agent {
  // Do not expose instance names to clients
  static options = { sendIdentityOnConnect: false };
}

When identity is disabled:

  • agent.identified stays false
  • agent.ready never resolves (use state updates instead)
  • onIdentity and onIdentityChange are never called

When to use custom routing

ScenarioApproach
Standard agent accessDefault /agents/{agent}/{name}
Instance from auth/sessionbasePath + getAgentByName + fetch
Clean URLs (no /agents/ prefix)basePath + custom routing
Legacy URL structurebasePath + custom routing
Complex routing logicCustom routing in Worker

Routing options

Both routeAgentRequest() and getAgentByName() accept options for customizing routing behavior.

CORS

For cross-origin requests (common when your frontend is on a different domain):

JavaScript
const response = await routeAgentRequest(request, env, {
  cors: true, // Enable default CORS headers
});

Or with custom CORS headers:

JavaScript
const response = await routeAgentRequest(request, env, {
  cors: {
    "Access-Control-Allow-Origin": "https://myapp.com",
    "Access-Control-Allow-Methods": "GET, POST, OPTIONS",
    "Access-Control-Allow-Headers": "Content-Type, Authorization",
  },
});

Location hints

For latency-sensitive applications, hint where the agent should run:

JavaScript
// With getAgentByName
const agent = await getAgentByName(env.MyAgent, "instance-name", {
  locationHint: "enam", // Eastern North America
});


// With routeAgentRequest (applies to all matched agents)
const response = await routeAgentRequest(request, env, {
  locationHint: "enam",
});

Available location hints: wnam, enam, sam, weur, eeur, apac, oc, afr, me

Jurisdiction

For data residency requirements:

JavaScript
// With getAgentByName
const agent = await getAgentByName(env.MyAgent, "instance-name", {
  jurisdiction: "eu", // EU jurisdiction
});


// With routeAgentRequest (applies to all matched agents)
const response = await routeAgentRequest(request, env, {
  jurisdiction: "eu",
});

Props

Since agents are instantiated by the runtime rather than constructed directly, props provides a way to pass initialization arguments:

JavaScript
const agent = await getAgentByName(env.MyAgent, "instance-name", {
  props: {
    userId: session.userId,
    config: { maxRetries: 3 },
  },
});

Props are passed to the agent's onStart lifecycle method:

JavaScript
class MyAgent extends Agent {
  userId;
  config;


  async onStart(props) {
    this.userId = props?.userId;
    this.config = props?.config;
  }
}

When using props with routeAgentRequest, the same props are passed to whichever agent matches the URL. This works well for universal context like authentication:

JavaScript
export default {
  async fetch(request, env) {
    const session = await getSession(request);
    return routeAgentRequest(request, env, {
      props: { userId: session.userId, role: session.role },
    });
  },
};

For agent-specific initialization, use getAgentByName instead where you control exactly which agent receives the props.

Hooks

routeAgentRequest supports hooks for intercepting requests before they reach agents:

JavaScript
const response = await routeAgentRequest(request, env, {
  onBeforeConnect: (req, lobby) => {
    // Called before WebSocket connections
    // Return a Response to reject, Request to modify, or void to continue
  },
  onBeforeRequest: (req, lobby) => {
    // Called before HTTP requests
    // Return a Response to reject, Request to modify, or void to continue
  },
});

These hooks are useful for authentication and validation. Refer to Cross-domain authentication for detailed examples.

Server-side agent access

You can access agents from your Worker code using getAgentByName() for RPC calls:

JavaScript
import { getAgentByName, routeAgentRequest } from "agents";


export default {
  async fetch(request, env) {
    const url = new URL(request.url);


    // API endpoint that interacts with an agent
    if (url.pathname === "/api/increment") {
      const counter = await getAgentByName(env.Counter, "global-counter");
      const newCount = await counter.increment();
      return Response.json({ count: newCount });
    }


    // Regular agent routing
    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  },
};

For options like locationHint, jurisdiction, and props, refer to Routing options.

Sub-paths and HTTP methods

Requests can include sub-paths after the instance name. These are passed to your agent's onRequest() handler:

/agents/api/v1/users     → agent: "api", instance: "v1", path: "/users"
/agents/api/v1/users/123 → agent: "api", instance: "v1", path: "/users/123"

Handle sub-paths in your agent:

JavaScript
export class API extends Agent {
  async onRequest(request) {
    const url = new URL(request.url);


    // url.pathname contains the full path including /agents/api/v1/...
    // Extract the sub-path after your agent's base path
    const path = url.pathname.replace(/^\/agents\/api\/[^/]+/, "");


    if (request.method === "GET" && path === "/users") {
      return Response.json(await this.getUsers());
    }


    if (request.method === "POST" && path === "/users") {
      const data = await request.json();
      return Response.json(await this.createUser(data));
    }


    return new Response("Not found", { status: 404 });
  }
}

Multiple agents

You can have multiple agent classes in one project. Each gets its own namespace:

JavaScript
// server.ts
export { Counter } from "./agents/counter";
export { ChatRoom } from "./agents/chat-room";
export { UserProfile } from "./agents/user-profile";


export default {
  async fetch(request, env) {
    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  },
};
 
{
  "durable_objects": {
    "bindings": [
      { "name": "Counter", "class_name": "Counter" },
      { "name": "ChatRoom", "class_name": "ChatRoom" },
      { "name": "UserProfile", "class_name": "UserProfile" },
    ],
  },
  "migrations": [
    {
      "tag": "v1",
      "new_sqlite_classes": ["Counter", "ChatRoom", "UserProfile"],
    },
  ],
}

Each agent is accessed via its own path:

/agents/counter/...
/agents/chat-room/...
/agents/user-profile/...

Request flow

Here is how a request flows through the system:

flowchart TD
    A["HTTP Request<br/>or WebSocket"] --> B["routeAgentRequest<br/>Parse URL path"]
    B --> C["Find binding in<br/>env by name"]
    C --> D["Get/create DO<br/>by instance ID"]
    D --> E["Agent Instance"]
    E --> F{"Protocol?"}
    F -->|WebSocket| G["onConnect(), onMessage"]
    F -->|HTTP| H["onRequest()"]

Routing with authentication

There are several ways to authenticate requests before they reach your agent.

Using authentication hooks

The routeAgentRequest() function provides onBeforeConnect and onBeforeRequest hooks for authentication:

JavaScript
import { Agent, routeAgentRequest } from "agents";


export default {
  async fetch(request, env) {
    return (
      (await routeAgentRequest(request, env, {
        // Run before WebSocket connections
        onBeforeConnect: async (request) => {
          const token = new URL(request.url).searchParams.get("token");
          if (!(await verifyToken(token, env))) {
            // Return a response to reject the connection
            return new Response("Unauthorized", { status: 401 });
          }
          // Return nothing to allow the connection
        },
        // Run before HTTP requests
        onBeforeRequest: async (request) => {
          const auth = request.headers.get("Authorization");
          if (!auth || !(await verifyAuth(auth, env))) {
            return new Response("Unauthorized", { status: 401 });
          }
        },
        // Optional: prepend a prefix to agent instance names
        prefix: "user-",
      })) ?? new Response("Not found", { status: 404 })
    );
  },
};

Manual authentication

Check authentication before calling routeAgentRequest():

JavaScript
export default {
  async fetch(request, env) {
    const url = new URL(request.url);


    // Protect agent routes
    if (url.pathname.startsWith("/agents/")) {
      const user = await authenticate(request, env);
      if (!user) {
        return new Response("Unauthorized", { status: 401 });
      }


      // Optionally, enforce that users can only access their own agents
      const instanceName = url.pathname.split("/")[3];
      if (instanceName !== `user-${user.id}`) {
        return new Response("Forbidden", { status: 403 });
      }
    }


    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  },
};

Using a framework (Hono)

If you are using a framework like Hono ↗, authenticate in middleware before calling the agent:

JavaScript
import { Agent, getAgentByName } from "agents";
import { Hono } from "hono";


const app = new Hono();


// Authentication middleware
app.use("/agents/*", async (c, next) => {
  const token = c.req.header("Authorization")?.replace("Bearer ", "");
  if (!token || !(await verifyToken(token, c.env))) {
    return c.json({ error: "Unauthorized" }, 401);
  }
  await next();
});


// Route to a specific agent
app.all("/agents/code-review/:id/*", async (c) => {
  const id = c.req.param("id");
  const agent = await getAgentByName(c.env.CodeReviewAgent, id);
  return agent.fetch(c.req.raw);
});


export default app;

For WebSocket authentication patterns (tokens in URLs, JWT refresh), refer to Cross-domain authentication.

Troubleshooting

Agent namespace not found

The error message lists available agents. Check:

  1. Agent class is exported from your entry point.
  2. Class name in code matches class_name in wrangler.jsonc.
  3. URL uses correct kebab-case name.

Request returns 404

  1. Verify the URL pattern: /agents/{agent-name}/{instance-name}.
  2. Check that routeAgentRequest() is called before your 404 handler.
  3. Ensure the response from routeAgentRequest() is returned (not just called).

WebSocket connection fails

  1. Do not modify the response from routeAgentRequest() for WebSocket upgrades.
  2. Ensure CORS is enabled if connecting from a different origin.
  3. Check browser dev tools for the actual error.

basePath not working

  1. Ensure your Worker handles the custom path and forwards to the agent.
  2. Use getAgentByName() + agent.fetch(request) to forward requests.
  3. The agent parameter is still required but ignored when basePath is set.
  4. Check that the server-side route matches the client's basePath.

API reference

routeAgentRequest(request, env, options?)

Routes a request to the appropriate agent.

ParameterTypeDescription
requestRequestThe incoming request
envEnvEnvironment with agent bindings
options.corsboolean | HeadersInitEnable CORS headers
options.propsRecord<string, unknown>Props passed to whichever agent handles request
options.locationHintstringPreferred location for agent instances
options.jurisdictionstringData jurisdiction for agent instances
options.onBeforeConnectFunctionCallback before WebSocket connections
options.onBeforeRequestFunctionCallback before HTTP requests

Returns: Promise<Response | undefined> - Response if matched, undefined if no agent route.

getAgentByName(namespace, name, options?)

Get an agent instance by name for server-side RPC or request forwarding.

ParameterTypeDescription
namespaceDurableObjectNamespace<T>Agent binding from env
namestringInstance name
options.locationHintstringPreferred location
options.jurisdictionstringData jurisdiction
options.propsRecord<string, unknown>Initialization properties for onStart

Returns: Promise<DurableObjectStub<T>> - Typed stub for calling agent methods or forwarding requests.

useAgent(options) / AgentClient options

Client connection options for custom routing:

OptionTypeDescription
agentstringAgent class name (required)
namestringInstance name (default: "default")
basePathstringFull URL path - bypasses agent/name URL construction
pathstringAdditional path to append to the URL
onIdentity(name, agent) => voidCalled when server sends identity
onIdentityChange(oldName, newName, oldAgent, newAgent) => voidCalled when identity changes on reconnect

Return value properties (React hook):

PropertyTypeDescription
namestringCurrent instance name (reactive)
agentstringCurrent agent class name (reactive)
identifiedbooleanWhether identity has been received (reactive)
readyPromise<void>Resolves when identity is received

Agent.options (server)

Static options for agent configuration:

OptionTypeDefaultDescription
hibernatebooleantrueWhether the agent should hibernate when inactive
sendIdentityOnConnectbooleantrueWhether to send identity to clients on connect
hungScheduleTimeoutSecondsnumber30Timeout before a running schedule is considered hung
JavaScript
class SecureAgent extends Agent {
  static options = { sendIdentityOnConnect: false };
}

Next steps

Client SDK Connect from browsers with useAgent and AgentClient.
Cross-domain authentication WebSocket authentication patterns.
Callable methods RPC from clients over WebSocket.
Configuration Set up agent bindings in wrangler.jsonc.