diff --git a/src/puter-js/src/modules/Email.js b/src/puter-js/src/modules/Email.js
index d87385ae8..98cb2836d 100644
--- a/src/puter-js/src/modules/Email.js
+++ b/src/puter-js/src/modules/Email.js
@@ -27,6 +27,11 @@ import * as utils from '../lib/utils.js';
  * Recipients who unsubscribe are dropped from future sends — they come
  * back in the result's `suppressed` array — and a send whose `to` list
  * is entirely unsubscribed is rejected.
+ *
+ * Each recipient gets a private delivery. A recipient whose delivery
+ * fails comes back in the result's `failed` array (everyone else got
+ * their copy — retry with just those addresses); the call only rejects
+ * when no recipient could be delivered.
  */
 class Email {
     /**
diff --git a/src/puter-js/types/modules/email.d.ts b/src/puter-js/types/modules/email.d.ts
index e865d970f..3b2b820a1 100644
--- a/src/puter-js/types/modules/email.d.ts
+++ b/src/puter-js/types/modules/email.d.ts
@@ -42,6 +42,12 @@ export interface EmailSendResult {
     cost: number;
     /** Recipients omitted because they opted out of this sender's mail. */
     suppressed: string[];
+    /**
+     * Recipients whose delivery attempt failed. Everyone else got their
+     * copy — retry with just these addresses. A send where every delivery
+     * fails rejects instead.
+     */
+    failed: string[];
 }
 
 /**