diff --git a/src/agent/client.ts b/src/agent/client.ts
index f7388ad..23fa9c6 100644
--- a/src/agent/client.ts
+++ b/src/agent/client.ts
@@ -1,3 +1,4 @@
+import { hostname } from "node:os";
 import Letta from "@letta-ai/letta-client";
 import packageJson from "../../package.json";
 import { LETTA_CLOUD_API_URL, refreshAccessToken } from "../auth/oauth";
@@ -20,7 +21,19 @@ export async function getClient() {
     // Refresh if token expires within 5 minutes
     if (expiresAt - now < 5 * 60 * 1000) {
       try {
-        const tokens = await refreshAccessToken(settings.refreshToken);
+        // Get or generate device ID (should always exist, but fallback just in case)
+        let deviceId = settings.deviceId;
+        if (!deviceId) {
+          deviceId = crypto.randomUUID();
+          settingsManager.updateSettings({ deviceId });
+        }
+        const deviceName = hostname();
+
+        const tokens = await refreshAccessToken(
+          settings.refreshToken,
+          deviceId,
+          deviceName,
+        );
 
         // Update settings with new token
         const updatedEnv = { ...settings.env };
diff --git a/src/auth/oauth.ts b/src/auth/oauth.ts
index a23871a..5ea10a5 100644
--- a/src/auth/oauth.ts
+++ b/src/auth/oauth.ts
@@ -68,7 +68,7 @@ export async function pollForToken(
   deviceCode: string,
   interval: number = 5,
   expiresIn: number = 900,
-  deviceId?: string,
+  deviceId: string,
   deviceName?: string,
 ): Promise<TokenResponse> {
   const startTime = Date.now();
@@ -88,7 +88,7 @@ export async function pollForToken(
             grant_type: "urn:ietf:params:oauth:grant-type:device_code",
             client_id: OAUTH_CONFIG.clientId,
             device_code: deviceCode,
-            ...(deviceId && { device_id: deviceId }),
+            device_id: deviceId,
             ...(deviceName && { device_name: deviceName }),
           }),
         },
@@ -138,6 +138,8 @@ export async function pollForToken(
  */
 export async function refreshAccessToken(
   refreshToken: string,
+  deviceId: string,
+  deviceName?: string,
 ): Promise<TokenResponse> {
   const response = await fetch(`${OAUTH_CONFIG.authBaseUrl}/api/oauth/token`, {
     method: "POST",
@@ -147,6 +149,8 @@ export async function refreshAccessToken(
       client_id: OAUTH_CONFIG.clientId,
       refresh_token: refreshToken,
       refresh_token_mode: "new",
+      device_id: deviceId,
+      ...(deviceName && { device_name: deviceName }),
     }),
   });