Add cold email notifier

apps/web/app/(app)/[emailAccountId]/assistant/ActionSteps.tsx

@@ -533,9 +533,16 @@ function ActionCard({
   const isDraftEmailWithoutManualContent =
     actionType === ActionType.DRAFT_EMAIL && !contentSetManually;
 
+  const isNotifySender = actionType === ActionType.NOTIFY_SENDER;
+
   const rightContent = (
     <>
-      {isDraftEmailWithoutManualContent ? (
+      {isNotifySender ? (
+        <div className="px-1 h-full flex items-center text-sm text-muted-foreground">
+          Sends an automated notification from Inbox Zero informing the sender
+          their email was filtered as cold outreach.
+        </div>
+      ) : isDraftEmailWithoutManualContent ? (
         <div className="px-1 h-full flex items-center text-sm text-muted-foreground">
           Our AI generates a draft reply from your email history and knowledge
           base.

apps/web/app/(app)/[emailAccountId]/assistant/ActionSummaryCard.tsx

@@ -203,6 +203,12 @@ export function ActionSummaryCard({
       summaryContent = `Folder: ${action.folderName?.value || "unset"}`;
       break;
 
+    case ActionType.NOTIFY_SENDER:
+      summaryContent = "Notify sender";
+      tooltipText =
+        "Sends an automated notification from Inbox Zero (not from your email) informing the sender their email was filtered as cold outreach.";
+      break;
+
     default:
       summaryContent = actionTypeLabel;
   }

apps/web/app/(app)/[emailAccountId]/assistant/AvailableActionsPanel.tsx

@@ -21,6 +21,7 @@ const actionNames: Record<ActionType, string> = {
   [ActionType.SEND_EMAIL]: "Send email",
   [ActionType.CALL_WEBHOOK]: "Call webhook",
   [ActionType.DIGEST]: "Add to digest",
+  [ActionType.NOTIFY_SENDER]: "Notify sender",
 };
 
 const actionTooltips: Partial<Record<ActionType, string>> = {

apps/web/app/(app)/[emailAccountId]/assistant/RuleForm.tsx

@@ -5,6 +5,7 @@ import { useRouter } from "next/navigation";
 import { type SubmitHandler, useFieldArray, useForm } from "react-hook-form";
 import { zodResolver } from "@hookform/resolvers/zod";
 import { usePostHog } from "posthog-js/react";
+import { env } from "@/env";
 import {
   PencilIcon,
   TrashIcon,
@@ -52,7 +53,6 @@ import { getRuleConfig } from "@/utils/rule/consts";
 import { RuleSectionCard } from "@/app/(app)/[emailAccountId]/assistant/RuleSectionCard";
 import { ConditionSteps } from "@/app/(app)/[emailAccountId]/assistant/ConditionSteps";
 import { ActionSteps } from "@/app/(app)/[emailAccountId]/assistant/ActionSteps";
-import { env } from "@/env";
 
 export function Rule({
   ruleId,
@@ -339,10 +339,21 @@ export function RuleForm({
         value: ActionType.CALL_WEBHOOK,
         icon: getActionIcon(ActionType.CALL_WEBHOOK),
       },
+      // NOTIFY_SENDER is only available for cold email rules
+      ...(rule.systemType === SystemType.COLD_EMAIL &&
+      env.NEXT_PUBLIC_IS_RESEND_CONFIGURED
+        ? [
+            {
+              label: "Notify sender",
+              value: ActionType.NOTIFY_SENDER,
+              icon: getActionIcon(ActionType.NOTIFY_SENDER),
+            },
+          ]
+        : []),
     ];
 
     return options;
-  }, [provider, terminology.label.action]);
+  }, [provider, terminology.label.action, rule.systemType]);
 
   const [isNameEditMode, setIsNameEditMode] = useState(alwaysEditMode);
   const [isDeleting, setIsDeleting] = useState(false);

apps/web/app/(app)/[emailAccountId]/assistant/constants.ts

@@ -10,6 +10,7 @@ import {
   WebhookIcon,
   FileTextIcon,
   FolderInputIcon,
+  BellIcon,
 } from "lucide-react";
 import { ActionType } from "@/generated/prisma/enums";
 
@@ -25,6 +26,7 @@ const ACTION_TYPE_COLORS = {
   [ActionType.CALL_WEBHOOK]: "bg-gray-500",
   [ActionType.DIGEST]: "bg-teal-500",
   [ActionType.MOVE_FOLDER]: "bg-emerald-500",
+  [ActionType.NOTIFY_SENDER]: "bg-amber-500",
 } as const;
 
 export const ACTION_TYPE_TEXT_COLORS = {
@@ -39,6 +41,7 @@ export const ACTION_TYPE_TEXT_COLORS = {
   [ActionType.CALL_WEBHOOK]: "text-gray-500",
   [ActionType.DIGEST]: "text-teal-500",
   [ActionType.MOVE_FOLDER]: "text-emerald-500",
+  [ActionType.NOTIFY_SENDER]: "text-amber-500",
 } as const;
 
 export const ACTION_TYPE_ICONS = {
@@ -53,6 +56,7 @@ export const ACTION_TYPE_ICONS = {
   [ActionType.CALL_WEBHOOK]: WebhookIcon,
   [ActionType.DIGEST]: FileTextIcon,
   [ActionType.MOVE_FOLDER]: FolderInputIcon,
+  [ActionType.NOTIFY_SENDER]: BellIcon,
 } as const;
 
 // Helper function to get action type from string (for RulesPrompt.tsx)

apps/web/app/(app)/[emailAccountId]/cold-email-blocker/ColdEmailContent.tsx

@@ -15,11 +15,11 @@ export function ColdEmailContent({ searchParam }: { searchParam?: string }) {
   const { emailAccountId } = useAccount();
 
   return (
-    <Tabs defaultValue="test" searchParam={searchParam}>
+    <Tabs defaultValue="cold-emails" searchParam={searchParam}>
       <TabsList>
-        <TabsTrigger value="test">Test</TabsTrigger>
         <TabsTrigger value="cold-emails">Cold Emails</TabsTrigger>
         <TabsTrigger value="rejected">Marked Not Cold</TabsTrigger>
+        <TabsTrigger value="test">Test</TabsTrigger>
         <TabsTrigger value="settings">Settings</TabsTrigger>
       </TabsList>
 

apps/web/app/(landing)/components/page.tsx

@@ -330,6 +330,11 @@ export default function Components() {
                   label: "Digest",
                   id: "digest",
                 },
+                {
+                  type: ActionType.NOTIFY_SENDER,
+                  label: "Notify sender",
+                  id: "notify_sender",
+                },
               ]}
               provider="gmail"
               labels={[{ id: "label", name: "Label" }]}

apps/web/components/PlanBadge.tsx

@@ -179,6 +179,8 @@ function getActionLabel(type: ActionType, provider: string) {
       return "Mark as spam";
     case ActionType.MARK_READ:
       return "Mark as read";
+    case ActionType.NOTIFY_SENDER:
+      return "Notify Sender";
     default:
       return capitalCase(type);
   }
@@ -223,6 +225,8 @@ export function getActionColor(actionType: ActionType): Color {
     case ActionType.CALL_WEBHOOK:
     case ActionType.DIGEST:
       return "purple";
+    case ActionType.NOTIFY_SENDER:
+      return "purple";
     default: {
       const exhaustiveCheck: never = actionType;
       return exhaustiveCheck;

apps/web/components/email-list/EmailMessage.tsx

@@ -25,6 +25,7 @@ import { EmailAttachments } from "@/components/email-list/EmailAttachments";
 import { Loading } from "@/components/Loading";
 import { MessageText } from "@/components/Typography";
 import { useAccount } from "@/providers/EmailAccountProvider";
+import { formatReplySubject } from "@/utils/email/subject";
 
 export function EmailMessage({
   message,
@@ -328,7 +329,7 @@ const prepareReplyingToEmail = (
     // If following an email from yourself, don't add "Re:" prefix
     subject: sentFromUser
       ? message.headers.subject
-      : `Re: ${message.headers.subject}`,
+      : formatReplySubject(message.headers.subject),
     headerMessageId: message.headers["message-id"]!,
     threadId: message.threadId!,
     // Keep original CC

apps/web/env.ts

@@ -190,6 +190,8 @@ export const env = createEnv({
     NEXT_PUBLIC_DIGEST_ENABLED: z.coerce.boolean().optional(),
     NEXT_PUBLIC_MEETING_BRIEFS_ENABLED: z.coerce.boolean().optional(),
     NEXT_PUBLIC_INTEGRATIONS_ENABLED: z.coerce.boolean().optional(),
+    // Derived from presence of RESEND_API_KEY
+    NEXT_PUBLIC_IS_RESEND_CONFIGURED: z.boolean().optional(),
   },
   // For Next.js >= 13.4.4, you only need to destructure client variables:
   experimental__runtimeEnv: {
@@ -251,5 +253,6 @@ export const env = createEnv({
       process.env.NEXT_PUBLIC_MEETING_BRIEFS_ENABLED,
     NEXT_PUBLIC_INTEGRATIONS_ENABLED:
       process.env.NEXT_PUBLIC_INTEGRATIONS_ENABLED,
+    NEXT_PUBLIC_IS_RESEND_CONFIGURED: !!process.env.RESEND_API_KEY,
   },
 });

apps/web/prisma/migrations/20251219012216_add_notify_sender_action_type/migration.sql

@@ -0,0 +1,2 @@
+-- AlterEnum
+ALTER TYPE "ActionType" ADD VALUE 'NOTIFY_SENDER';

apps/web/prisma/schema.prisma

@@ -1051,6 +1051,7 @@ enum ActionType {
   // TRACK_THREAD // @deprecated - No longer used. We rely on rule SystemType instead to run this.
   DIGEST
   MOVE_FOLDER
+  NOTIFY_SENDER // Sends notification from Inbox Zero (not user's email). Only for cold email rules.
   // SUMMARIZE
   // SNOOZE
   // ADD_TO_DO

apps/web/utils/action-display.tsx

@@ -2,6 +2,7 @@ import { ActionType } from "@/generated/prisma/enums";
 import { getEmailTerminology } from "@/utils/terminology";
 import {
   ArchiveIcon,
+  BellIcon,
   FolderInputIcon,
   ForwardIcon,
   ReplyIcon,
@@ -76,6 +77,8 @@ export function getActionDisplay(
       return "Digest";
     case ActionType.CALL_WEBHOOK:
       return "Call Webhook";
+    case ActionType.NOTIFY_SENDER:
+      return "Notify Sender";
     default: {
       const exhaustiveCheck: never = action.type;
       return exhaustiveCheck;
@@ -107,6 +110,8 @@ export function getActionIcon(actionType: ActionType) {
       return WebhookIcon;
     case ActionType.DIGEST:
       return NewspaperIcon;
+    case ActionType.NOTIFY_SENDER:
+      return BellIcon;
     default: {
       const exhaustiveCheck: never = actionType;
       return exhaustiveCheck;

apps/web/utils/action-item.ts

@@ -149,6 +149,9 @@ export const actionInputs: Record<
       },
     ],
   },
+  [ActionType.NOTIFY_SENDER]: {
+    fields: [],
+  },
 };
 
 export function getActionFields(fields: Action | ExecutedAction | undefined) {
@@ -275,6 +278,9 @@ export function sanitizeActionFields(
         url: action.url ?? null,
       };
     }
+    case ActionType.NOTIFY_SENDER: {
+      return base;
+    }
     default:
       // biome-ignore lint/correctness/noSwitchDeclarations: intentional exhaustive check
       const exhaustiveCheck: never = action.type;

apps/web/utils/actions/rule.validation.ts

@@ -26,6 +26,7 @@ const zodActionType = z.enum([
   ActionType.MARK_READ,
   ActionType.DIGEST,
   ActionType.MOVE_FOLDER,
+  ActionType.NOTIFY_SENDER,
 ]);
 
 const zodConditionType = z.enum([ConditionType.AI, ConditionType.STATIC]);

apps/web/utils/ai/actions.ts

@@ -10,6 +10,9 @@ import { filterNullProperties } from "@/utils";
 import { labelMessageAndSync } from "@/utils/label.server";
 import { hasVariables } from "@/utils/template";
 import prisma from "@/utils/prisma";
+import { sendColdEmailNotification } from "@/utils/cold-email/send-notification";
+import { extractEmailAddress } from "@/utils/email";
+import { captureException } from "@/utils/error";
 
 const MODULE = "ai-actions";
 
@@ -73,6 +76,8 @@ export const runActionFunction = async (options: {
       return digest(opts);
     case ActionType.MOVE_FOLDER:
       return move_folder(opts);
+    case ActionType.NOTIFY_SENDER:
+      return notify_sender(opts);
     default:
       throw new Error(`Unknown action: ${action}`);
   }
@@ -321,6 +326,44 @@ const move_folder: ActionFunction<{ folderId?: string | null }> = async ({
   await client.moveThreadToFolder(email.threadId, userEmail, args.folderId);
 };
 
+const notify_sender: ActionFunction<Record<string, unknown>> = async ({
+  email,
+  userEmail,
+  logger,
+}) => {
+  const senderEmail = extractEmailAddress(email.headers.from);
+  if (!senderEmail) {
+    logger.error("Could not extract sender email for notify_sender action");
+    return;
+  }
+
+  const result = await sendColdEmailNotification({
+    senderEmail,
+    recipientEmail: userEmail,
+    originalSubject: email.headers.subject,
+    originalMessageId: email.headers["message-id"],
+    logger,
+  });
+
+  if (!result.success) {
+    // Best-effort: don't fail the whole rule run if notification can't be sent.
+    logger.error("Cold email notification failed", {
+      senderEmail,
+      error: result.error,
+    });
+
+    captureException(
+      new Error(result.error ?? "Cold email notification failed"),
+      {
+        extra: { actionType: ActionType.NOTIFY_SENDER, senderEmail },
+        sampleRate: 0.01,
+      },
+      userEmail,
+    );
+    return;
+  }
+};
+
 async function lazyUpdateActionLabelId({
   labelName,
   labelId,

apps/web/utils/cold-email/send-notification.ts

@@ -0,0 +1,55 @@
+import { sendColdEmailNotification as sendColdEmailNotificationViaResend } from "@inboxzero/resend";
+import { env } from "@/env";
+import { getErrorMessage } from "@/utils/error";
+import type { Logger } from "@/utils/logger";
+import { formatReplySubject } from "@/utils/email/subject";
+
+export async function sendColdEmailNotification({
+  senderEmail,
+  recipientEmail,
+  originalSubject,
+  originalMessageId,
+  logger,
+}: {
+  senderEmail: string; // The cold emailer we're notifying
+  recipientEmail: string; // The user who received the cold email
+  originalSubject: string;
+  originalMessageId?: string; // Message-ID of the original email for threading
+  logger: Logger;
+}): Promise<{ success: boolean; error?: string }> {
+  if (!env.RESEND_API_KEY) {
+    logger.warn("Resend not configured, skipping cold email notification");
+    return { success: false, error: "Resend not configured" };
+  }
+
+  const subject = formatReplySubject(originalSubject);
+
+  try {
+    const result = await sendColdEmailNotificationViaResend({
+      from: env.RESEND_FROM_EMAIL,
+      to: senderEmail,
+      replyTo: recipientEmail,
+      subject,
+      inReplyTo: originalMessageId,
+      emailProps: {
+        baseUrl: env.NEXT_PUBLIC_BASE_URL,
+      },
+    });
+
+    logger.info("Cold email notification sent", {
+      senderEmail,
+      messageId: result.data?.id,
+    });
+
+    return { success: true };
+  } catch (error) {
+    logger.error("Error sending cold email notification", {
+      error,
+      senderEmail,
+    });
+    return {
+      success: false,
+      error: error instanceof Error ? error.message : "Unknown error",
+    };
+  }
+}

apps/web/utils/email/subject.ts

@@ -5,6 +5,10 @@
  */
 export function formatReplySubject(subject: string): string {
   const trimmed = (subject ?? "").trim();
+  // Avoid "Re: " with no subject
+  if (!trimmed) {
+    return "Re: (no subject)";
+  }
   // Avoid duplicate "Re:" prefix (case-insensitive check)
   if (/^re:/i.test(trimmed)) {
     return trimmed;