diff --git a/src/app/api/insights/generate/route.ts b/src/app/api/insights/generate/route.ts
index 2180ace0c..a6d53d23b 100644
--- a/src/app/api/insights/generate/route.ts
+++ b/src/app/api/insights/generate/route.ts
@@ -11,6 +11,7 @@
  * write breaks that convergence — the settling seam tests pin the client
  * half, this comment is the server half of the contract.
  */
+import { withBriefingGeneratedAt } from "@/lib/insights/briefing-generated-at";
 import { prisma } from "@/lib/db";
 import { auditLog } from "@/lib/auth/audit";
 import {
@@ -1051,7 +1052,9 @@ export const POST = apiHandler((request: NextRequest) =>
       },
       data: {
         insightsCachedAt: new Date(),
-        insightsCachedText: JSON.stringify(insights),
+        insightsCachedText: JSON.stringify(
+          withBriefingGeneratedAt(insights, new Date()),
+        ),
         insightsCachedLocale: locale,
         insightsSnapshotHash: hashInsightSnapshot({
           features: compactFeatures,
diff --git a/src/lib/daily/__tests__/briefing-today.test.ts b/src/lib/daily/__tests__/briefing-today.test.ts
index 0be476d9f..a3b877539 100644
--- a/src/lib/daily/__tests__/briefing-today.test.ts
+++ b/src/lib/daily/__tests__/briefing-today.test.ts
@@ -142,7 +142,7 @@ describe("briefingForToday", () => {
   it("drops a pulse signal whose last reading was yesterday at 08:50", () => {
     const out = briefingForToday(BRIEFING, {
       ...BERLIN,
-      updatedAt: "2026-10-05T04:00:00Z",
+      generatedAt: "2026-10-05T04:00:00Z",
       lastSeenAt: (type) => (type === "PULSE" ? "2026-10-04T06:50:00Z" : null),
     });
     expect(out?.signalsOfDay?.map((s) => s.sourceMetric)).toEqual(["sleep"]);
@@ -151,7 +151,7 @@ describe("briefingForToday", () => {
   it("keeps a pulse signal measured today, with its delta in whole beats", () => {
     const out = briefingForToday(BRIEFING, {
       ...BERLIN,
-      updatedAt: "2026-10-05T04:00:00Z",
+      generatedAt: "2026-10-05T04:00:00Z",
       lastSeenAt: (type) => (type === "PULSE" ? "2026-10-05T06:50:00Z" : null),
     });
     expect(out?.signalsOfDay?.[0]?.delta).toBe(
@@ -164,16 +164,26 @@ describe("briefingForToday", () => {
     expect(
       briefingForToday(BRIEFING, {
         ...BERLIN,
-        updatedAt: "2026-10-04T21:30:00Z",
+        generatedAt: "2026-10-04T21:30:00Z",
         lastSeenAt: () => "2026-10-04T21:00:00Z",
       }),
     ).toBeNull();
   });
 
+  it("serves no briefing whose generation moment is unknown", () => {
+    expect(
+      briefingForToday(BRIEFING, {
+        ...BERLIN,
+        generatedAt: null,
+        lastSeenAt: () => "2026-10-05T06:50:00Z",
+      }),
+    ).toBeNull();
+  });
+
   it("decides the day in the reader's zone", () => {
     // 05:00 UTC on the 5th is the evening of the 4th in Los Angeles.
     const ctx = {
-      updatedAt: "2026-10-05T05:00:00Z",
+      generatedAt: "2026-10-05T05:00:00Z",
       lastSeenAt: () => "2026-10-05T05:00:00Z",
       language: "en" as const,
     };
diff --git a/src/lib/daily/__tests__/load-digest.test.ts b/src/lib/daily/__tests__/load-digest.test.ts
index 6544fd576..fb459be1e 100644
--- a/src/lib/daily/__tests__/load-digest.test.ts
+++ b/src/lib/daily/__tests__/load-digest.test.ts
@@ -363,6 +363,67 @@ describe("loadDailyDigest — AI parts", () => {
   });
 });
 
+describe("loadDailyDigest — the briefing's own day", () => {
+  const BRIEFING = {
+    paragraph: "Last night's sleep came in a little short of your usual.",
+    signalsOfDay: [
+      {
+        sourceMetric: "sleep",
+        tone: "info",
+        headline: "Shorter night",
+        nudge: "An earlier night would suit it.",
+        delta: null,
+      },
+    ],
+    keyFindings: [],
+  };
+
+  function withBriefing(cachedText: string) {
+    vi.mocked(readDashboardSnapshotCached).mockResolvedValueOnce({
+      ...SNAPSHOT,
+      // The row was stamped this morning, as every warm stamps it.
+      body: {
+        ...SNAPSHOT.body,
+        briefing: BRIEFING,
+        briefingUpdatedAt: "2026-07-17T02:30:00.000Z",
+      },
+    } as never);
+    return { ...USER, insightsCachedText: cachedText } as User;
+  }
+
+  it("does not serve yesterday's text that a warm only re-stamped", async () => {
+    // Generated yesterday; the unchanged-hash warm at 04:30 refreshed only
+    // insightsCachedAt.
+    const user = withBriefing(
+      JSON.stringify({
+        dailyBriefing: BRIEFING,
+        briefingGeneratedAt: "2026-07-16T02:30:00.000Z",
+      }),
+    );
+    const digest = await loadDailyDigest(user, NOW);
+    expect(digest.briefingLead).toBeNull();
+    expect(digest.topSignal).toBeNull();
+  });
+
+  it("does not serve a payload that predates the generation moment", async () => {
+    const user = withBriefing(JSON.stringify({ dailyBriefing: BRIEFING }));
+    const digest = await loadDailyDigest(user, NOW);
+    expect(digest.topSignal).toBeNull();
+  });
+
+  it("serves text generated today", async () => {
+    const user = withBriefing(
+      JSON.stringify({
+        dailyBriefing: BRIEFING,
+        briefingGeneratedAt: "2026-07-17T02:30:00.000Z",
+      }),
+    );
+    const digest = await loadDailyDigest(user, NOW);
+    expect(digest.briefingLead).toBe(BRIEFING.paragraph);
+    expect(digest.topSignal?.sourceMetric).toBe("sleep");
+  });
+});
+
 /** A reminder row as the preventive read selects it; due this morning. */
 function reminderRow(over: Record<string, unknown> = {}) {
   return {
diff --git a/src/lib/daily/briefing-today.ts b/src/lib/daily/briefing-today.ts
index e4c2280f2..4ca2b7720 100644
--- a/src/lib/daily/briefing-today.ts
+++ b/src/lib/daily/briefing-today.ts
@@ -161,8 +161,13 @@ export function formatSignalDelta(
 }
 
 export interface BriefingForTodayContext {
-  /** When the cached briefing was written (ISO), or null when unknown. */
-  updatedAt: string | null;
+  /**
+   * When the briefing's content was generated (ISO, from the payload's
+   * `briefingGeneratedAt`), or null when the payload predates the field.
+   * Never the cache row's `insightsCachedAt`: that moves on every warm,
+   * including the unchanged-hash refresh that keeps yesterday's text.
+   */
+  generatedAt: string | null;
   /** The newest reading of a measurement type (ISO), or null when none. */
   lastSeenAt: (type: string) => string | null;
   /** The reader's zone and today's day key in it. */
@@ -173,8 +178,8 @@ export interface BriefingForTodayContext {
 }
 
 /**
- * The briefing as the Today surfaces may use it: null when it was written on
- * an earlier calendar day, otherwise with every reading-backed signal whose
+ * The briefing as the Today surfaces may use it: null when its content was
+ * generated on an earlier calendar day, or at an unknown time, otherwise with every reading-backed signal whose
  * metric was not measured today removed and every remaining delta re-read at
  * its metric's precision.
  */
@@ -184,8 +189,8 @@ export function briefingForToday(
 ): DailyBriefing | null {
   if (!briefing) return null;
   if (
-    ctx.updatedAt !== null &&
-    userDayKey(new Date(ctx.updatedAt), ctx.timezone) !== ctx.todayLocalDate
+    ctx.generatedAt === null ||
+    userDayKey(new Date(ctx.generatedAt), ctx.timezone) !== ctx.todayLocalDate
   ) {
     return null;
   }
diff --git a/src/lib/daily/load-digest.ts b/src/lib/daily/load-digest.ts
index a786cbbf1..03dfa95ed 100644
--- a/src/lib/daily/load-digest.ts
+++ b/src/lib/daily/load-digest.ts
@@ -84,6 +84,7 @@ import { addDays, dayDiff } from "@/lib/cycle/day-math";
 import { makeFormatters, resolveIntlLocale } from "@/lib/format-locale";
 import { vitalDisplayDecimals } from "@/lib/measurements/vital-precision";
 import { briefingForToday } from "@/lib/daily/briefing-today";
+import { readBriefingGeneratedAt } from "@/lib/insights/briefing-generated-at";
 import type {
   DateFormatPreference,
   TimeFormatPreference,
@@ -938,7 +939,7 @@ export async function loadDailyDigest(
       // earlier day is not served as today's read, and a signal whose
       // metric has no reading today is dropped (`briefing-today.ts`).
       briefing: briefingForToday(snapshot.briefing, {
-        updatedAt: snapshot.briefingUpdatedAt,
+        generatedAt: readBriefingGeneratedAt(user.insightsCachedText),
         lastSeenAt: (type) =>
           snapshot.tiles.lastSeenByType[type]?.lastSeenAt ?? null,
         timezone: user.timezone,
diff --git a/src/lib/insights/__tests__/briefing-generated-at.test.ts b/src/lib/insights/__tests__/briefing-generated-at.test.ts
new file mode 100644
index 000000000..21517e1ee
--- /dev/null
+++ b/src/lib/insights/__tests__/briefing-generated-at.test.ts
@@ -0,0 +1,27 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  readBriefingGeneratedAt,
+  withBriefingGeneratedAt,
+} from "@/lib/insights/briefing-generated-at";
+
+describe("briefing generation moment", () => {
+  it("round-trips through the stored JSON text", () => {
+    const at = new Date("2026-10-05T04:30:00.000Z");
+    const text = JSON.stringify(
+      withBriefingGeneratedAt({ dailyBriefing: { paragraph: "x" } }, at),
+    );
+    expect(readBriefingGeneratedAt(text)).toBe(at.toISOString());
+  });
+
+  it("is unknown for a payload that predates it, or does not parse", () => {
+    expect(readBriefingGeneratedAt(JSON.stringify({ dailyBriefing: {} }))).toBe(
+      null,
+    );
+    expect(readBriefingGeneratedAt("not json")).toBeNull();
+    expect(readBriefingGeneratedAt(null)).toBeNull();
+    expect(
+      readBriefingGeneratedAt({ briefingGeneratedAt: "yesterday-ish" }),
+    ).toBeNull();
+  });
+});
diff --git a/src/lib/insights/__tests__/comprehensive-briefing-reroll.test.ts b/src/lib/insights/__tests__/comprehensive-briefing-reroll.test.ts
index b805f1e75..4d83ec073 100644
--- a/src/lib/insights/__tests__/comprehensive-briefing-reroll.test.ts
+++ b/src/lib/insights/__tests__/comprehensive-briefing-reroll.test.ts
@@ -178,6 +178,10 @@ describe("daily-briefing re-roll on unchanged data", () => {
       { headline: "BP steady", tone: "good" },
     ]);
     expect(stored.summary).toBe("stable summary");
+    // New text, so a new generation moment.
+    expect(Date.parse(stored.briefingGeneratedAt)).toBeGreaterThan(
+      Date.now() - 60_000,
+    );
     expect(data.insightsBriefingRerollDate).toBe(todayKey);
     expect(invalidateUserInsights).toHaveBeenCalledWith("u1");
   });
@@ -223,5 +227,14 @@ describe("daily-briefing re-roll on unchanged data", () => {
           .insightsBriefingRerollDate !== undefined,
     );
     expect(write).toBeTruthy();
+    // The stamp refresh keeps yesterday's text and its generation moment:
+    // it writes no text at all.
+    expect(
+      userUpdate.mock.calls.some(
+        (c) =>
+          (c[0] as { data: Record<string, unknown> }).data
+            .insightsCachedText !== undefined,
+      ),
+    ).toBe(false);
   });
 });
diff --git a/src/lib/insights/__tests__/comprehensive-generate-force.test.ts b/src/lib/insights/__tests__/comprehensive-generate-force.test.ts
index 1bf266d3f..5eb22ab81 100644
--- a/src/lib/insights/__tests__/comprehensive-generate-force.test.ts
+++ b/src/lib/insights/__tests__/comprehensive-generate-force.test.ts
@@ -310,6 +310,12 @@ describe("generateComprehensiveInsight — content-hash gate (v1.16.8)", () => {
     expect(data.insightsSnapshotHash).toBe(FEATURES_HASH);
     // The cache row records the language it was generated in.
     expect(data.insightsCachedLocale).toBe("de");
+    // New text carries the moment it was generated, which the "is this
+    // briefing from today" check reads instead of insightsCachedAt.
+    const stored = JSON.parse(data.insightsCachedText as string);
+    expect(Date.parse(stored.briefingGeneratedAt)).toBeGreaterThan(
+      Date.now() - 60_000,
+    );
     // v1.16.8 — the blanket per-status eviction is gone.
     expect(auditDeleteMany).not.toHaveBeenCalled();
   });
diff --git a/src/lib/insights/briefing-generated-at.ts b/src/lib/insights/briefing-generated-at.ts
new file mode 100644
index 000000000..903b7626f
--- /dev/null
+++ b/src/lib/insights/briefing-generated-at.ts
@@ -0,0 +1,45 @@
+/**
+ * When the cached briefing's content was written, as opposed to when the
+ * cache row was last touched.
+ *
+ * `User.insightsCachedAt` moves on every warm, including the content-hash
+ * short-circuit that keeps yesterday's text and only refreshes the stamp.
+ * A "is this briefing from today?" check read off that column therefore
+ * passed for text written the day before. The moment the content itself was
+ * produced rides inside the cached payload instead, written only where new
+ * text is written: a full generation (the warm and the on-demand route) and
+ * the daily paragraph re-roll. The plain stamp refresh leaves it alone.
+ *
+ * A payload without the field predates it, and its age is unknown: the
+ * readers treat it as not from today, which is the safe side (the hero falls
+ * back to its own lead and a warm is asked for).
+ */
+
+/** The top-level key on the cached insight payload. */
+export const BRIEFING_GENERATED_AT_KEY = "briefingGeneratedAt";
+
+/** The payload with the generation moment set. */
+export function withBriefingGeneratedAt<T extends object>(
+  payload: T,
+  at: Date,
+): T & { [BRIEFING_GENERATED_AT_KEY]: string } {
+  return { ...payload, [BRIEFING_GENERATED_AT_KEY]: at.toISOString() };
+}
+
+/**
+ * The generation moment of a cached payload (an object or its stored JSON
+ * text), or null when it carries none or does not parse.
+ */
+export function readBriefingGeneratedAt(payload: unknown): string | null {
+  let value: unknown = payload;
+  if (typeof payload === "string") {
+    try {
+      value = JSON.parse(payload);
+    } catch {
+      return null;
+    }
+  }
+  if (value === null || typeof value !== "object") return null;
+  const at = (value as Record<string, unknown>)[BRIEFING_GENERATED_AT_KEY];
+  return typeof at === "string" && !Number.isNaN(Date.parse(at)) ? at : null;
+}
diff --git a/src/lib/insights/comprehensive-generate.ts b/src/lib/insights/comprehensive-generate.ts
index 5469072e9..c6d4c3162 100644
--- a/src/lib/insights/comprehensive-generate.ts
+++ b/src/lib/insights/comprehensive-generate.ts
@@ -18,6 +18,7 @@
  * NO synchronous request lifecycle: the cron path runs entirely on
  * pg-boss, never inside an HTTP handler.
  */
+import { withBriefingGeneratedAt } from "@/lib/insights/briefing-generated-at";
 import pLimit from "p-limit";
 import { prisma } from "@/lib/db";
 import {
@@ -298,7 +299,12 @@ async function rerollBriefingParagraph(args: {
     ...(cachedBriefing as Record<string, unknown>),
     paragraph: freshParagraph,
   };
-  const merged = { ...cached, dailyBriefing: mergedBriefing };
+  // A re-rolled paragraph is new text, so it carries a new generation
+  // moment; the plain stamp refresh that a miss falls back to does not.
+  const merged = withBriefingGeneratedAt(
+    { ...cached, dailyBriefing: mergedBriefing },
+    new Date(),
+  );
   return { text: JSON.stringify(merged), providerType };
 }
 
@@ -1443,7 +1449,9 @@ export async function generateComprehensiveInsight(
     workingProviderType,
     {
       insightsCachedAt: new Date(),
-      insightsCachedText: JSON.stringify(insights),
+      insightsCachedText: JSON.stringify(
+        withBriefingGeneratedAt(insights, new Date()),
+      ),
       insightsCachedLocale: locale,
       insightsSnapshotHash: snapshotHash,
     },