Routing

How requests are routed to agents, naming patterns, and URL structures

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:

URL	Agent Class	Instance
/agents/counter/user-123	Counter	user-123
/agents/chat-room/lobby	ChatRoom	lobby
/agents/my-agent/default	MyAgent	default

Name Resolution

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

Class Name	URL 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 these all work:

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

Basic Usage

routeAgentRequest()

The main entry point for agent routing. Handles both HTTP requests and WebSocket upgrades:

import { routeAgentRequest } from "agents";

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext) {
    // 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 });
  }
};

getAgentByName()

Get a specific agent instance for server-side RPC calls or request forwarding:

import { getAgentByName, routeAgentRequest } from "agents";

export default {
  async fetch(request: Request, env: 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 })
    );
  }
};

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:

// 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:

// 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:

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

Dynamic Naming

Generate instance names based on context:

// 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()}`
});

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):

Default CORS

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

Location Hints

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

// 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:

// 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:

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:

class MyAgent extends Agent<Env, State> {
  private userId?: string;
  private config?: { maxRetries: number };

  async onStart(props?: { userId: string; config: { maxRetries: number } }) {
    this.userId = props?.userId;
    this.config = props?.config;
  }
}

For McpAgent, props are automatically stored and accessible via this.props.

Hooks

routeAgentRequest supports hooks for intercepting requests before they reach agents:

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
  }
});

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:

// 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 (e.g., from auth/session)
• You’re integrating with an existing URL structure

Server-Side Instance Selection

When using basePath, the server must handle routing:

export default {
  async fetch(request: Request, env: 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 })
    );
  }
};

Receiving the Instance Identity (Client-Side)

When using basePath, the client doesn’t know which instance it connected to until the server tells it:

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

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

Multiple Agents

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

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

export default {
  async fetch(request: Request, env: Env) {
    return (
      (await routeAgentRequest(request, env)) ??
      new Response("Not found", { status: 404 })
    );
  }
};

wrangler.jsonc

{
  "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/...

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 won’t connect

1. Don’t 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.

request · Request · required

The incoming request

env · Env · required

Environment with agent bindings

options.cors · boolean | HeadersInit

Enable CORS headers

options.props · Record<string, unknown>

Props passed to whichever agent handles the request

options.locationHint · string

Preferred location for agent instances

options.jurisdiction · string

Data jurisdiction for agent instances

options.onBeforeConnect · Function

Callback before WebSocket connections

options.onBeforeRequest · Function

Callback 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.

namespace · DurableObjectNamespace<T> · required

Agent binding from env

name · string · required

Instance name

options.locationHint · string

Preferred location

options.jurisdiction · string

Data jurisdiction

options.props · Record<string, unknown>

Initialization properties for onStart

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