diff --git a/lib/emails/__tests__/hasDeliveredEmail.test.ts b/lib/emails/__tests__/hasDeliveredEmail.test.ts
new file mode 100644
index 00000000..c62f34c9
--- /dev/null
+++ b/lib/emails/__tests__/hasDeliveredEmail.test.ts
@@ -0,0 +1,23 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+import { hasDeliveredEmail } from "../hasDeliveredEmail";
+
+const mockCount = vi.fn();
+vi.mock("@/lib/supabase/email_send_log/countDeliveredEmails", () => ({
+  countDeliveredEmails: (...args: unknown[]) => mockCount(...args),
+}));
+
+describe("hasDeliveredEmail", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("returns true when at least one email was delivered", async () => {
+    mockCount.mockResolvedValue(2);
+    expect(await hasDeliveredEmail("chat-1")).toBe(true);
+    expect(mockCount).toHaveBeenCalledWith("chat-1");
+  });
+
+  it("returns false when none were delivered", async () => {
+    mockCount.mockResolvedValue(0);
+    expect(await hasDeliveredEmail("chat-1")).toBe(false);
+  });
+});
diff --git a/lib/emails/__tests__/logEmailAttempt.test.ts b/lib/emails/__tests__/logEmailAttempt.test.ts
new file mode 100644
index 00000000..a352a9e3
--- /dev/null
+++ b/lib/emails/__tests__/logEmailAttempt.test.ts
@@ -0,0 +1,56 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+import { logEmailAttempt } from "../logEmailAttempt";
+
+const mockInsert = vi.fn();
+vi.mock("@/lib/supabase/email_send_log/insertEmailSendLog", () => ({
+  insertEmailSendLog: (...args: unknown[]) => mockInsert(...args),
+}));
+
+describe("logEmailAttempt", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockInsert.mockResolvedValue({ error: null });
+  });
+
+  it("records a sent attempt with parsed body, lengths, and resend id", async () => {
+    await logEmailAttempt({
+      rawBody: JSON.stringify({ to: ["a@b.com"], html: "<p>hi</p>" }),
+      status: "sent",
+      accountId: "acc-1",
+      to: ["a@b.com"],
+      subject: "S",
+      html: "<p>hi</p>",
+      chatId: "chat-1",
+      resendId: "re_123",
+    });
+    expect(mockInsert).toHaveBeenCalledTimes(1);
+    const row = mockInsert.mock.calls[0][0];
+    expect(row.status).toBe("sent");
+    expect(row.body_parsed).toBe(true);
+    expect(row.account_id).toBe("acc-1");
+    expect(row.to_count).toBe(1);
+    expect(row.html_length).toBe("<p>hi</p>".length);
+    expect(row.resend_id).toBe("re_123");
+    expect(row.chat_id).toBe("chat-1");
+  });
+
+  it("marks body_parsed false for a malformed body and still logs", async () => {
+    await logEmailAttempt({ rawBody: '{"to":[', status: "rejected" });
+    const row = mockInsert.mock.calls[0][0];
+    expect(row.body_parsed).toBe(false);
+    expect(row.status).toBe("rejected");
+    expect(row.account_id).toBeNull();
+  });
+
+  it("truncates a large raw body to 10000 chars", async () => {
+    await logEmailAttempt({ rawBody: "x".repeat(20000), status: "rejected" });
+    const row = mockInsert.mock.calls[0][0];
+    expect(row.raw_body.length).toBe(10000);
+  });
+
+  it("never throws when the insert fails", async () => {
+    mockInsert.mockRejectedValue(new Error("db down"));
+    await expect(logEmailAttempt({ rawBody: "{}", status: "rejected" })).resolves.toBeUndefined();
+  });
+});
diff --git a/lib/emails/__tests__/sendEmailHandler.test.ts b/lib/emails/__tests__/sendEmailHandler.test.ts
index 3b5fa6e8..03610bb1 100644
--- a/lib/emails/__tests__/sendEmailHandler.test.ts
+++ b/lib/emails/__tests__/sendEmailHandler.test.ts
@@ -4,6 +4,7 @@ import { sendEmailHandler } from "../sendEmailHandler";
 
 const mockValidateSendEmailBody = vi.fn();
 const mockProcessAndSendEmail = vi.fn();
+const mockLogEmailAttempt = vi.fn();
 
 vi.mock("@/lib/emails/validateSendEmailBody", () => ({
   validateSendEmailBody: (...args: unknown[]) => mockValidateSendEmailBody(...args),
@@ -13,6 +14,10 @@ vi.mock("@/lib/emails/processAndSendEmail", () => ({
   processAndSendEmail: (...args: unknown[]) => mockProcessAndSendEmail(...args),
 }));
 
+vi.mock("@/lib/emails/logEmailAttempt", () => ({
+  logEmailAttempt: (...args: unknown[]) => mockLogEmailAttempt(...args),
+}));
+
 vi.mock("@/lib/networking/getCorsHeaders", () => ({
   getCorsHeaders: vi.fn(() => ({ "Access-Control-Allow-Origin": "*" })),
 }));
@@ -60,6 +65,9 @@ describe("sendEmailHandler", () => {
         room_id: "chat-1",
       }),
     );
+    expect(mockLogEmailAttempt).toHaveBeenCalledWith(
+      expect.objectContaining({ status: "sent", resendId: "resend-id-1" }),
+    );
   });
 
   it("propagates the NextResponse from validateSendEmailBody (auth/validation/recipient errors)", async () => {
@@ -69,6 +77,9 @@ describe("sendEmailHandler", () => {
     const response = await sendEmailHandler(createRequest());
     expect(response.status).toBe(403);
     expect(mockProcessAndSendEmail).not.toHaveBeenCalled();
+    expect(mockLogEmailAttempt).toHaveBeenCalledWith(
+      expect.objectContaining({ status: "rejected" }),
+    );
   });
 
   it("returns 502 when Resend delivery fails", async () => {
@@ -77,5 +88,8 @@ describe("sendEmailHandler", () => {
     expect(response.status).toBe(502);
     const json = await response.json();
     expect(json.error).toBe("resend boom");
+    expect(mockLogEmailAttempt).toHaveBeenCalledWith(
+      expect.objectContaining({ status: "send_failed", error: "resend boom" }),
+    );
   });
 });
diff --git a/lib/emails/hasDeliveredEmail.ts b/lib/emails/hasDeliveredEmail.ts
new file mode 100644
index 00000000..86d86856
--- /dev/null
+++ b/lib/emails/hasDeliveredEmail.ts
@@ -0,0 +1,14 @@
+import { countDeliveredEmails } from "@/lib/supabase/email_send_log/countDeliveredEmails";
+
+/**
+ * Whether a chat/run delivered at least one non-empty email (per
+ * `email_send_log`). The building block for the "verify-the-send" guarantee:
+ * a report task that completes without a delivered email should be flagged
+ * rather than reported as a silent success.
+ *
+ * @param chatId - The chat/run id.
+ * @returns true if ≥1 'sent' email is logged for the chat.
+ */
+export async function hasDeliveredEmail(chatId: string): Promise<boolean> {
+  return (await countDeliveredEmails(chatId)) > 0;
+}
diff --git a/lib/emails/logEmailAttempt.ts b/lib/emails/logEmailAttempt.ts
new file mode 100644
index 00000000..969d2ea0
--- /dev/null
+++ b/lib/emails/logEmailAttempt.ts
@@ -0,0 +1,59 @@
+import { insertEmailSendLog } from "@/lib/supabase/email_send_log/insertEmailSendLog";
+
+/** Cap the stored raw body so a 12KB+ HTML report doesn't bloat the log row. */
+const MAX_RAW_BODY = 10000;
+
+export type EmailAttemptStatus = "sent" | "send_failed" | "rejected";
+
+export type EmailAttemptLog = {
+  /** The raw request body, as received (used to record body_parsed + a truncated copy). */
+  rawBody: string;
+  status: EmailAttemptStatus;
+  accountId?: string | null;
+  to?: string[];
+  subject?: string;
+  html?: string;
+  text?: string;
+  chatId?: string;
+  resendId?: string;
+  error?: string;
+};
+
+/**
+ * Records one POST /api/emails attempt in `email_send_log` so a send can be
+ * debugged days later without the (ephemeral) sandbox — capturing whether the
+ * body parsed, a truncated copy of it, the resolved fields, and the outcome.
+ *
+ * Best-effort: this never throws. A logging failure must not affect the send.
+ *
+ * @param attempt - The attempt to record.
+ */
+export async function logEmailAttempt(attempt: EmailAttemptLog): Promise<void> {
+  let bodyParsed = false;
+  try {
+    if (attempt.rawBody && attempt.rawBody.trim()) {
+      JSON.parse(attempt.rawBody);
+      bodyParsed = true;
+    }
+  } catch {
+    bodyParsed = false;
+  }
+
+  try {
+    await insertEmailSendLog({
+      account_id: attempt.accountId ?? null,
+      chat_id: attempt.chatId ?? null,
+      status: attempt.status,
+      body_parsed: bodyParsed,
+      raw_body: attempt.rawBody ? attempt.rawBody.slice(0, MAX_RAW_BODY) : null,
+      to_count: attempt.to?.length ?? null,
+      subject: attempt.subject ?? null,
+      html_length: attempt.html?.length ?? null,
+      text_length: attempt.text?.length ?? null,
+      resend_id: attempt.resendId ?? null,
+      error: attempt.error ?? null,
+    });
+  } catch {
+    // Best-effort logging — swallow so the email send result is unaffected.
+  }
+}
diff --git a/lib/emails/sendEmailHandler.ts b/lib/emails/sendEmailHandler.ts
index 8eac17e5..6a884db9 100644
--- a/lib/emails/sendEmailHandler.ts
+++ b/lib/emails/sendEmailHandler.ts
@@ -2,6 +2,16 @@ import { NextRequest, NextResponse } from "next/server";
 import { getCorsHeaders } from "@/lib/networking/getCorsHeaders";
 import { validateSendEmailBody } from "@/lib/emails/validateSendEmailBody";
 import { processAndSendEmail } from "@/lib/emails/processAndSendEmail";
+import { logEmailAttempt } from "@/lib/emails/logEmailAttempt";
+
+/** Read the raw request body without consuming it (validation reads the original). */
+async function readRawBody(request: NextRequest): Promise<string> {
+  try {
+    return await request.clone().text();
+  } catch {
+    return "";
+  }
+}
 
 /**
  * Handler for POST /api/emails.
@@ -13,12 +23,19 @@ import { processAndSendEmail } from "@/lib/emails/processAndSendEmail";
  * Body validation, auth, and the recipient restriction all live in
  * `validateSendEmailBody`.
  *
+ * Every attempt — sent, send-failed, and rejected (e.g. an empty/malformed
+ * body) — is recorded in `email_send_log` via `logEmailAttempt`, so a send can
+ * be debugged days later without the ephemeral sandbox that built the request.
+ *
  * @param request - The request object.
  * @returns A NextResponse with the send result.
  */
 export async function sendEmailHandler(request: NextRequest): Promise<NextResponse> {
+  const rawBody = await readRawBody(request);
+
   const validated = await validateSendEmailBody(request);
   if (validated instanceof NextResponse) {
+    await logEmailAttempt({ rawBody, status: "rejected" });
     return validated;
   }
 
@@ -35,12 +52,35 @@ export async function sendEmailHandler(request: NextRequest): Promise<NextRespon
   });
 
   if (result.success === false) {
+    await logEmailAttempt({
+      rawBody,
+      status: "send_failed",
+      accountId: validated.accountId,
+      to,
+      subject,
+      html,
+      text,
+      chatId: chat_id,
+      error: result.error,
+    });
     return NextResponse.json(
       { status: "error", error: result.error },
       { status: 502, headers: getCorsHeaders() },
     );
   }
 
+  await logEmailAttempt({
+    rawBody,
+    status: "sent",
+    accountId: validated.accountId,
+    to,
+    subject,
+    html,
+    text,
+    chatId: chat_id,
+    resendId: result.id,
+  });
+
   return NextResponse.json(
     { success: true, message: result.message, id: result.id },
     { status: 200, headers: getCorsHeaders() },
diff --git a/lib/supabase/email_send_log/countDeliveredEmails.ts b/lib/supabase/email_send_log/countDeliveredEmails.ts
new file mode 100644
index 00000000..39a86ac3
--- /dev/null
+++ b/lib/supabase/email_send_log/countDeliveredEmails.ts
@@ -0,0 +1,20 @@
+import supabase from "../serverClient";
+
+/**
+ * Counts the **delivered, non-empty** emails recorded for a chat/run in
+ * `email_send_log` (status = 'sent'). Used to verify that a task which was
+ * supposed to email actually delivered one. Returns 0 on error.
+ *
+ * @param chatId - The chat/run id (email_send_log.chat_id).
+ * @returns The number of 'sent' rows for the chat.
+ */
+export async function countDeliveredEmails(chatId: string): Promise<number> {
+  const { count, error } = await supabase
+    .from("email_send_log")
+    .select("id", { count: "exact", head: true })
+    .eq("chat_id", chatId)
+    .eq("status", "sent");
+
+  if (error) return 0;
+  return count ?? 0;
+}
diff --git a/lib/supabase/email_send_log/insertEmailSendLog.ts b/lib/supabase/email_send_log/insertEmailSendLog.ts
new file mode 100644
index 00000000..cb16241a
--- /dev/null
+++ b/lib/supabase/email_send_log/insertEmailSendLog.ts
@@ -0,0 +1,16 @@
+import supabase from "../serverClient";
+import type { Database } from "@/types/database.types";
+
+/**
+ * Inserts one row into `email_send_log`. Best-effort: callers should not let a
+ * logging failure affect the email send, so errors are returned, never thrown.
+ *
+ * @param row - The email_send_log insert payload.
+ * @returns `{ error }` — null on success.
+ */
+export async function insertEmailSendLog(
+  row: Database["public"]["Tables"]["email_send_log"]["Insert"],
+): Promise<{ error: unknown }> {
+  const { error } = await supabase.from("email_send_log").insert(row);
+  return { error };
+}
diff --git a/types/database.types.ts b/types/database.types.ts
index 872750b7..3e15dda8 100644
--- a/types/database.types.ts
+++ b/types/database.types.ts
@@ -8,6 +8,54 @@ export type Database = {
   };
   public: {
     Tables: {
+      email_send_log: {
+        Row: {
+          account_id: string | null;
+          body_parsed: boolean;
+          chat_id: string | null;
+          created_at: string;
+          error: string | null;
+          html_length: number | null;
+          id: string;
+          raw_body: string | null;
+          resend_id: string | null;
+          status: string;
+          subject: string | null;
+          text_length: number | null;
+          to_count: number | null;
+        };
+        Insert: {
+          account_id?: string | null;
+          body_parsed?: boolean;
+          chat_id?: string | null;
+          created_at?: string;
+          error?: string | null;
+          html_length?: number | null;
+          id?: string;
+          raw_body?: string | null;
+          resend_id?: string | null;
+          status: string;
+          subject?: string | null;
+          text_length?: number | null;
+          to_count?: number | null;
+        };
+        Update: {
+          account_id?: string | null;
+          body_parsed?: boolean;
+          chat_id?: string | null;
+          created_at?: string;
+          error?: string | null;
+          html_length?: number | null;
+          id?: string;
+          raw_body?: string | null;
+          resend_id?: string | null;
+          status?: string;
+          subject?: string | null;
+          text_length?: number | null;
+          to_count?: number | null;
+        };
+        Relationships: [];
+      };
       account_api_keys: {
         Row: {
           account: string | null;