diff --git a/src/utils/axios-client.ts b/src/utils/axios-client.ts
index 957835c..7354732 100644
--- a/src/utils/axios-client.ts
+++ b/src/utils/axios-client.ts
@@ -1,6 +1,7 @@
 import axios from "axios";
 import { isInIFrame } from "./common.js";
 import { v4 as uuidv4 } from "uuid";
+import { getAnalyticsSessionId } from "../modules/analytics.js";
 import type { Base44ErrorJSON } from "./axios-client.types.js";
 
 /**
@@ -176,6 +177,16 @@ export function createAxiosClient({
   client.interceptors.request.use((config) => {
     if (typeof window !== "undefined") {
       config.headers.set("X-Origin-URL", window.location.href);
+      // On unauthenticated clients, attach a stable anonymous visitor id so the
+      // backend can support anonymous agent access (conversation grouping +
+      // ownership). Authenticated clients are identified by their token instead.
+      // Reuses the persisted analytics session id so an anonymous agent
+      // conversation and that visitor's analytics events share one identity.
+      // (Hardening this id to crypto-strength + decoupling from analytics is a
+      // tracked follow-up.)
+      if (!token) {
+        config.headers.set("X-Base44-Anonymous-Id", getAnalyticsSessionId());
+      }
     }
     const requestId = uuidv4();
     (config as any).requestId = requestId;
diff --git a/src/utils/socket-utils.ts b/src/utils/socket-utils.ts
index 2914c4f..e05f150 100644
--- a/src/utils/socket-utils.ts
+++ b/src/utils/socket-utils.ts
@@ -1,5 +1,6 @@
 import { Socket, io } from "socket.io-client";
 import { getAccessToken } from "./auth-utils.js";
+import { getAnalyticsSessionId } from "../modules/analytics.js";
 
 export interface RoomsSocketConfig {
   serverUrl: string;
@@ -37,13 +38,23 @@ function initializeSocket(
   config: RoomsSocketConfig,
   handlers: Partial<RoomsSocketEventsMap["listen"]>
 ) {
+  // On unauthenticated clients, send a stable anonymous visitor id on the
+  // handshake so the backend can verify room access for anonymous agent
+  // conversations (mirrors the X-Base44-Anonymous-Id HTTP header). Authenticated
+  // clients are identified by their token instead.
+  const resolvedToken = config.token ?? getAccessToken();
+  const query: Record<string, string | null | undefined> = {
+    app_id: config.appId,
+    token: resolvedToken,
+  };
+  if (!resolvedToken) {
+    query.anonymous_id = getAnalyticsSessionId();
+  }
+
   const socket = io(config.serverUrl, {
     path: config.mountPath,
     transports: config.transports,
-    query: {
-      app_id: config.appId,
-      token: config.token ?? getAccessToken(),
-    },
+    query,
   }) as Socket<RoomsSocketEventsMap["listen"], RoomsSocketEventsMap["emit"]>;
 
   socket.on("connect", async () => {
diff --git a/tests/unit/anonymous-visitor-header.test.ts b/tests/unit/anonymous-visitor-header.test.ts
new file mode 100644
index 0000000..b362608
--- /dev/null
+++ b/tests/unit/anonymous-visitor-header.test.ts
@@ -0,0 +1,66 @@
+import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
+import { createAxiosClient } from "../../src/utils/axios-client.ts";
+import { getAnalyticsSessionId } from "../../src/modules/analytics.ts";
+
+const ANALYTICS_SESSION_ID_KEY = "base44_analytics_session_id";
+
+function makeLocalStorage() {
+  const store = new Map<string, string>();
+  return {
+    getItem: (k: string) => (store.has(k) ? store.get(k)! : null),
+    setItem: (k: string, v: string) => {
+      store.set(k, v);
+    },
+    removeItem: (k: string) => {
+      store.delete(k);
+    },
+    clear: () => store.clear(),
+  };
+}
+
+beforeEach(() => {
+  const localStorage = makeLocalStorage();
+  vi.stubGlobal("window", {
+    location: { href: "https://my-app.base44.app/" },
+    localStorage,
+  });
+  vi.stubGlobal("localStorage", localStorage);
+});
+
+afterEach(() => {
+  vi.unstubAllGlobals();
+});
+
+async function captureRequestHeaders(token?: string) {
+  const client = createAxiosClient({ baseURL: "https://api", token });
+  let captured: any;
+  client.defaults.adapter = async (config) => {
+    captured = config;
+    return { data: {}, status: 200, statusText: "OK", headers: {}, config };
+  };
+  await client.get("/conversations");
+  return captured.headers;
+}
+
+describe("anonymous visitor header", () => {
+  test("unauthenticated client sends X-Base44-Anonymous-Id", async () => {
+    const headers = await captureRequestHeaders(undefined);
+    expect(headers.get("X-Base44-Anonymous-Id")).toBeTruthy();
+    expect(headers.get("Authorization")).toBeFalsy();
+  });
+
+  test("header value is the persisted analytics session id (unified identity)", async () => {
+    const headers = await captureRequestHeaders(undefined);
+    const sessionId = getAnalyticsSessionId();
+    expect(headers.get("X-Base44-Anonymous-Id")).toBe(sessionId);
+    expect(
+      (globalThis as any).localStorage.getItem(ANALYTICS_SESSION_ID_KEY)
+    ).toBe(sessionId);
+  });
+
+  test("authenticated client sends Authorization, not the anonymous header", async () => {
+    const headers = await captureRequestHeaders("a-real-token");
+    expect(headers.get("X-Base44-Anonymous-Id")).toBeFalsy();
+    expect(headers.get("Authorization")).toBe("Bearer a-real-token");
+  });
+});
diff --git a/tests/unit/socket-utils.test.ts b/tests/unit/socket-utils.test.ts
index f012a4c..2d58f29 100644
--- a/tests/unit/socket-utils.test.ts
+++ b/tests/unit/socket-utils.test.ts
@@ -1,4 +1,5 @@
 import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
+import { io } from "socket.io-client";
 import { RoomsSocket } from "../../src/utils/socket-utils.ts";
 
 const socketMock = vi.hoisted(() => ({
@@ -19,6 +20,14 @@ vi.mock("socket.io-client", () => ({
   })),
 }));
 
+vi.mock("../../src/utils/auth-utils.ts", () => ({
+  getAccessToken: vi.fn(() => undefined),
+}));
+
+vi.mock("../../src/modules/analytics.ts", () => ({
+  getAnalyticsSessionId: vi.fn(() => "anon-session-123"),
+}));
+
 describe("RoomsSocket", () => {
   beforeEach(() => {
     socketMock.disconnect.mockClear();
@@ -31,6 +40,39 @@ describe("RoomsSocket", () => {
     vi.useRealTimers();
   });
 
+  describe("handshake auth params", () => {
+    const baseConfig = {
+      serverUrl: "https://api.base44.test",
+      mountPath: "/socket.io/",
+      transports: ["websocket"],
+      appId: "test-app-id",
+    };
+
+    function lastHandshakeQuery(): Record<string, unknown> {
+      const opts = vi.mocked(io).mock.calls.at(-1)?.[1] as
+        | { query?: Record<string, unknown> }
+        | undefined;
+      return opts?.query ?? {};
+    }
+
+    test("sends a stable anonymous_id and no token when unauthenticated", () => {
+      RoomsSocket({ config: { ...baseConfig } });
+
+      const query = lastHandshakeQuery();
+      expect(query.app_id).toBe("test-app-id");
+      expect(query.anonymous_id).toBe("anon-session-123");
+      expect(query.token).toBeUndefined();
+    });
+
+    test("sends the token and no anonymous_id when authenticated", () => {
+      RoomsSocket({ config: { ...baseConfig, token: "test-token" } });
+
+      const query = lastHandshakeQuery();
+      expect(query.token).toBe("test-token");
+      expect(query.anonymous_id).toBeUndefined();
+    });
+  });
+
   function createRoomsSocket() {
     return RoomsSocket({
       config: {