From fe6c2e281b3b20c0afd50e10e1ee5d7192aa76df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc-Andr=C3=A9=20Bombeck?= <mbombeck@gmail.com>
Date: Fri, 26 Jun 2026 23:57:37 +0200
Subject: [PATCH] =?UTF-8?q?feat(insights):=20ambient=20narrative=20presenc?=
 =?UTF-8?q?e=20=E2=80=94=20callbacks,=20tension=20verdict,=20streaks,=20MI?=
 =?UTF-8?q?=20moves?=
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Add a deterministic narrative layer the Coach narrates rather than invents:

- Briefing callbacks + forward-looks: the daily briefing recalls the prior
  period and points ahead, anchored to a figure, one callback per surface.
- Tension Verdict: when the readiness composite's contributors disagree
  (good sleep but a rising resting pulse), surface a brief honest internal
  read on the health-score card. A real clinical red-flag is never reconciled
  away into a calm verdict.
- Streaks + return-to-baseline: a pure detector over a DAY-bucket series
  closes a worry once a metric returns inside the personal MAD band after a
  genuine out-of-band run; a gap day breaks a streak.
- Coach prompt: add develop-discrepancy, roll-with-resistance, and an
  anti-persuasion clause; ratchet PROMPT_VERSION.

The tension flag and streak event are computed server-side; the card lines
render resolved fields and the model narrates them.
---
 src/components/insights/daily-briefing.tsx    |  42 ++++
 src/components/insights/health-score-card.tsx |  92 +++++++-
 .../coach/__tests__/derived-snapshot.test.ts  | 139 +++++++++++-
 .../ai/coach/__tests__/system-prompt.test.ts  |  36 +++
 src/lib/ai/coach/derived-snapshot.ts          | 117 +++++++++-
 src/lib/ai/coach/system-prompt.ts             |  93 ++++++++
 src/lib/ai/prompts/insight-generator.ts       |   2 +-
 .../__tests__/streak-detector.test.ts         | 137 ++++++++++++
 src/lib/insights/streak-detector.ts           | 210 ++++++++++++++++++
 9 files changed, 863 insertions(+), 5 deletions(-)
 create mode 100644 src/lib/insights/__tests__/streak-detector.test.ts
 create mode 100644 src/lib/insights/streak-detector.ts

diff --git a/src/components/insights/daily-briefing.tsx b/src/components/insights/daily-briefing.tsx
index d56baf4ac..92d06564c 100644
--- a/src/components/insights/daily-briefing.tsx
+++ b/src/components/insights/daily-briefing.tsx
@@ -123,6 +123,20 @@ interface DailyBriefingProps {
    * comparison toggle migrates here from the hero in commit 5.
    */
   metaSlot?: React.ReactNode;
+  /**
+   * v1.21.2 (A4) — server-resolved callback + forward-look. The briefing
+   * recalls the prior period and points ahead ("as I noted Monday, your sleep
+   * was short; it's recovered since — worth watching tonight"). Both strings
+   * are already localised and figure-anchored by the resolver; the card only
+   * renders them. One callback per surface — absent (the common case) when no
+   * prior narrative recall is on file.
+   */
+  memory?: {
+    /** The recall of the prior-period read, anchored to a figure. */
+    recall: string;
+    /** The forward-look pointing ahead. */
+    forward: string;
+  } | null;
 }
 
 const METRIC_ICON: Record<
@@ -335,6 +349,7 @@ export function DailyBriefing({
   noProvider = false,
   noProviderStale = false,
   metaSlot,
+  memory = null,
 }: DailyBriefingProps) {
   const { t } = useTranslations();
 
@@ -374,6 +389,33 @@ export function DailyBriefing({
             // looser `space-y-4`, which read as taller than its neighbours on
             // the overview. One token, no new spacing scale.
             <div className="space-y-3">
+              {/* v1.21.2 (A4) — callback + forward-look. Recalls the prior
+                  period and points ahead, both server-resolved and
+                  figure-anchored. Leads the card so the briefing opens by
+                  closing the loop on what it noted last, then looks forward. */}
+              {memory && (
+                <div
+                  data-slot="daily-briefing-memory"
+                  className="border-border/60 bg-card/40 space-y-1 rounded-md border px-3 py-2"
+                >
+                  <p
+                    data-slot="daily-briefing-memory-recall"
+                    className="text-muted-foreground text-xs leading-snug"
+                  >
+                    {t("insights.briefing.memory.recall", {
+                      text: memory.recall,
+                    })}
+                  </p>
+                  <p
+                    data-slot="daily-briefing-memory-forward"
+                    className="text-foreground/80 text-xs leading-snug"
+                  >
+                    {t("insights.briefing.memory.forward", {
+                      text: memory.forward,
+                    })}
+                  </p>
+                </div>
+              )}
               {/* v1.4.27 B1 — the leading narrative paragraph dropped.
                 The hero strip subtitle on `/insights` already renders
                 the same `briefing.paragraph` text directly above this
diff --git a/src/components/insights/health-score-card.tsx b/src/components/insights/health-score-card.tsx
index 1c92e616e..646ef15bc 100644
--- a/src/components/insights/health-score-card.tsx
+++ b/src/components/insights/health-score-card.tsx
@@ -1,7 +1,15 @@
 "use client";
 
 import { useId, useMemo, useState } from "react";
-import { ArrowDown, ArrowUp, ChevronDown, Minus, Moon } from "lucide-react";
+import {
+  ArrowDown,
+  ArrowUp,
+  ChevronDown,
+  CornerDownLeft,
+  Minus,
+  Moon,
+  Scale,
+} from "lucide-react";
 import { useTranslations } from "@/lib/i18n/context";
 import { cn } from "@/lib/utils";
 import { HealthScoreDeltaExplainer } from "./health-score-delta-explainer";
@@ -96,6 +104,34 @@ export interface HealthScoreCardProps {
    * active, not the episode details. Default off (the common case).
    */
   restModeActive?: boolean;
+  /**
+   * v1.21.2 (A5) — Tension Verdict line. The server resolves the honest
+   * "internal read" when the readiness/recovery composite's contributors
+   * DISAGREE (good sleep but a rising resting pulse, …). The card renders it
+   * as one short line: the favourable contributor, the unfavourable one, and
+   * the band the composite lands on. Purely DTO-rendered — the card never
+   * recomputes the disagreement. Absent (the common case) when the
+   * contributors agree.
+   */
+  tension?: {
+    band: HealthScoreBand;
+    /** Favourable contributors, already localised by the resolver. */
+    positive: string[];
+    /** Unfavourable contributors, already localised by the resolver. */
+    negative: string[];
+  } | null;
+  /**
+   * v1.21.2 (A6) — return-to-baseline line. Present only when a metric has
+   * come BACK inside the user's own usual range after a prior out-of-band run.
+   * Actively closes a worry ("back inside your usual range after last week's
+   * dip"). Server-resolved DTO; the label is already localised.
+   */
+  returnToBand?: {
+    /** The metric's display label, already localised by the resolver. */
+    metricLabel: string;
+    /** Days the metric has now sat back inside its range. */
+    daysInside: number;
+  } | null;
 }
 
 type ComponentKey = keyof HealthScoreCardProps["components"];
@@ -178,6 +214,8 @@ export function HealthScoreCard({
   initiallyExpanded = false,
   moodEnabled = true,
   restModeActive = false,
+  tension = null,
+  returnToBand = null,
 }: HealthScoreCardProps) {
   const { t, locale } = useTranslations();
   // The asOf timestamps render under the source pill as a tooltip
@@ -201,6 +239,13 @@ export function HealthScoreCard({
     if (Number.isNaN(parsed.getTime())) return null;
     return asOfFormatter.format(parsed);
   };
+  // v1.21.2 (A5) — locale-aware conjunction list for the Tension Verdict's
+  // favourable / unfavourable contributor lists ("sleep and mood" / "resting
+  // heart rate, HRV balance, and mood"). Memoised per locale.
+  const listFormatter = useMemo(
+    () => new Intl.ListFormat(locale, { style: "long", type: "conjunction" }),
+    [locale],
+  );
   const [expanded, setExpanded] = useState(initiallyExpanded);
   // `useId` keeps the aria-controls/section-id pair unique even when
   // the card is mounted twice on the same page (lg+ hero strip vs
@@ -418,6 +463,51 @@ export function HealthScoreCard({
           </p>
         )}
 
+        {/* v1.21.2 (A5) — Tension Verdict. The honest "internal read" when the
+            composite's contributors disagree, resolved server-side and rendered
+            as one short line. The card never recomputes the disagreement; it
+            only renders the resolved favourable / unfavourable contributors and
+            the band the composite lands on. */}
+        {tension &&
+          tension.positive.length > 0 &&
+          tension.negative.length > 0 && (
+            <p
+              data-slot="health-score-card-tension"
+              data-band={tension.band}
+              className="text-muted-foreground inline-flex items-start gap-1.5 text-[11px] leading-relaxed"
+            >
+              <Scale className="mt-0.5 size-3 shrink-0" aria-hidden="true" />
+              <span>
+                {t("insights.tension.label", {
+                  positive: listFormatter.format(tension.positive),
+                  negative: listFormatter.format(tension.negative),
+                  band: t(`insights.tension.contributor.${tension.band}`),
+                })}
+              </span>
+            </p>
+          )}
+
+        {/* v1.21.2 (A6) — return-to-baseline. Present only when a metric came
+            back inside the user's own usual range after a prior out-of-band run.
+            Actively closes a worry rather than reporting a number. */}
+        {returnToBand && (
+          <p
+            data-slot="health-score-card-return-to-band"
+            className="text-success/90 inline-flex items-start gap-1.5 text-[11px] leading-relaxed"
+          >
+            <CornerDownLeft
+              className="mt-0.5 size-3 shrink-0"
+              aria-hidden="true"
+            />
+            <span>
+              {t("insights.streak.returnLabel", {
+                metric: returnToBand.metricLabel,
+                count: returnToBand.daysInside,
+              })}
+            </span>
+          </p>
+        )}
+
         <ul
           data-slot="health-score-card-components"
           // v1.8.5 W4a — the always-visible "Zusammensetzung" breakdown is
diff --git a/src/lib/ai/coach/__tests__/derived-snapshot.test.ts b/src/lib/ai/coach/__tests__/derived-snapshot.test.ts
index 7a3704f00..83132cc46 100644
--- a/src/lib/ai/coach/__tests__/derived-snapshot.test.ts
+++ b/src/lib/ai/coach/__tests__/derived-snapshot.test.ts
@@ -12,7 +12,12 @@ vi.mock("@/lib/db", () => ({
 
 import { computeDerivedMetric } from "@/lib/insights/derived";
 import { prisma } from "@/lib/db";
-import { buildDerivedSnapshotBlock } from "../derived-snapshot";
+import {
+  buildDerivedSnapshotBlock,
+  deriveTension,
+  TENSION_HIGH_SCORE,
+  TENSION_LOW_SCORE,
+} from "../derived-snapshot";
 
 const compute = computeDerivedMetric as unknown as ReturnType<typeof vi.fn>;
 const whoopFindFirst = prisma.measurement.findFirst as unknown as ReturnType<
@@ -166,4 +171,136 @@ describe("buildDerivedSnapshotBlock", () => {
       },
     });
   });
+
+  it("attaches a TENSION flag when readiness contributors disagree", async () => {
+    // Good sleep (high) but a suppressed HRV-balance + elevated resting pulse
+    // (both low) — a genuine internal disagreement the band hides.
+    compute.mockImplementation(async (args?: { metric?: string }) => {
+      if (args?.metric === "READINESS")
+        return ok({
+          score: 58,
+          band: "yellow",
+          components: [
+            { key: "sleep", value: 90, weight: 0.3 },
+            { key: "hrv", value: 30, weight: 0.3 },
+            { key: "rhr", value: 35, weight: 0.3 },
+            { key: "mood", value: 60, weight: 0.1 },
+          ],
+        });
+      return insufficient;
+    });
+    const block = await buildDerivedSnapshotBlock("u1", PROFILE, NOW);
+    expect(block!.TENSION).toBeDefined();
+    expect(block!.TENSION!.fired).toBe(true);
+    expect(block!.TENSION!.band).toBe("yellow");
+    expect(block!.TENSION!.positive).toEqual(["sleep"]);
+    expect(block!.TENSION!.negative).toEqual([
+      "HRV balance",
+      "resting heart rate",
+    ]);
+    // No coincident flag fired (DB read fails-soft to null), so no red-flag.
+    expect(block!.TENSION!.clinicalOverride).toBe(false);
+  });
+
+  it("omits TENSION when the contributors agree", async () => {
+    compute.mockImplementation(async (args?: { metric?: string }) => {
+      if (args?.metric === "READINESS")
+        return ok({
+          score: 82,
+          band: "green",
+          components: [
+            { key: "sleep", value: 90, weight: 0.3 },
+            { key: "hrv", value: 85, weight: 0.3 },
+            { key: "rhr", value: 80, weight: 0.3 },
+          ],
+        });
+      return insufficient;
+    });
+    const block = await buildDerivedSnapshotBlock("u1", PROFILE, NOW);
+    expect(block!.READINESS).toBeDefined();
+    expect(block!.TENSION).toBeUndefined();
+  });
+});
+
+describe("deriveTension (pure)", () => {
+  it("fires only when at least one contributor sits on each side", () => {
+    const fired = deriveTension(
+      [
+        { key: "sleep", value: TENSION_HIGH_SCORE },
+        { key: "rhr", value: TENSION_LOW_SCORE },
+      ],
+      "yellow",
+      false,
+    );
+    expect(fired).not.toBeNull();
+    expect(fired!.positive).toEqual(["sleep"]);
+    expect(fired!.negative).toEqual(["resting heart rate"]);
+  });
+
+  it("returns null when every contributor is favourable", () => {
+    expect(
+      deriveTension(
+        [
+          { key: "sleep", value: 90 },
+          { key: "hrv", value: 85 },
+        ],
+        "green",
+        false,
+      ),
+    ).toBeNull();
+  });
+
+  it("returns null when every contributor is unfavourable", () => {
+    expect(
+      deriveTension(
+        [
+          { key: "sleep", value: 20 },
+          { key: "hrv", value: 30 },
+        ],
+        "red",
+        false,
+      ),
+    ).toBeNull();
+  });
+
+  it("ignores neutral-band contributors (neither side)", () => {
+    // A mid-range contributor (between the low and high cuts) is neither
+    // favourable nor unfavourable, so on its own it cannot make a tension.
+    const mid = Math.floor((TENSION_HIGH_SCORE + TENSION_LOW_SCORE) / 2);
+    expect(
+      deriveTension(
+        [
+          { key: "sleep", value: mid },
+          { key: "hrv", value: mid },
+        ],
+        "yellow",
+        false,
+      ),
+    ).toBeNull();
+  });
+
+  it("ignores null (absent) contributors", () => {
+    expect(
+      deriveTension(
+        [
+          { key: "sleep", value: 90 },
+          { key: "rhr", value: null },
+        ],
+        "yellow",
+        false,
+      ),
+    ).toBeNull();
+  });
+
+  it("carries the clinical-override bit through unchanged", () => {
+    const fired = deriveTension(
+      [
+        { key: "sleep", value: 90 },
+        { key: "rhr", value: 20 },
+      ],
+      "red",
+      true,
+    );
+    expect(fired!.clinicalOverride).toBe(true);
+  });
 });
diff --git a/src/lib/ai/coach/__tests__/system-prompt.test.ts b/src/lib/ai/coach/__tests__/system-prompt.test.ts
index b9f887683..5231463db 100644
--- a/src/lib/ai/coach/__tests__/system-prompt.test.ts
+++ b/src/lib/ai/coach/__tests__/system-prompt.test.ts
@@ -118,6 +118,28 @@ describe("getCoachSystemPrompt — EN", () => {
     expect(prompt).toMatch(/0–21/);
     expect(prompt).toMatch(/0–100/);
   });
+
+  it("carries the v1.21.2 narrative-presence clauses (A4/A5/A6/A7)", () => {
+    // A4 — briefing-style callback + forward-look from the memory block.
+    expect(prompt).toMatch(/17\. Recall \+ look ahead/);
+    expect(prompt).toMatch(/priorNarrative/);
+    expect(prompt).toMatch(/trendMemory/);
+    // A5 — Tension Verdict with the clinical-floors override.
+    expect(prompt).toMatch(/18\. Tension Verdict/);
+    expect(prompt).toMatch(/"TENSION" flag/);
+    expect(prompt).toMatch(/CLINICAL-FLOORS OVERRIDE/);
+    expect(prompt).toMatch(/clinicalOverride/);
+    expect(prompt).toMatch(/NEVER reconcile it\s+away into a calm verdict/i);
+    // A6 — streaks + return-to-baseline.
+    expect(prompt).toMatch(/19\. Streaks \+ return-to-baseline/);
+    expect(prompt).toMatch(/returnEvent/);
+    expect(prompt).toMatch(/back inside your usual range/i);
+    // A7 — MI freebies + anti-persuasion (Chain-of-Ethic).
+    expect(prompt).toMatch(/20\. Motivational-interviewing freebies/);
+    expect(prompt).toMatch(/DEVELOP DISCREPANCY/);
+    expect(prompt).toMatch(/ROLL WITH RESISTANCE/);
+    expect(prompt).toMatch(/Chain-of-Ethic/);
+  });
 });
 
 describe("getCoachSystemPrompt — DE", () => {
@@ -181,6 +203,20 @@ describe("getCoachSystemPrompt — DE", () => {
     expect(prompt).toMatch(/mmol\/L/);
     expect(prompt).toMatch(/min[\s\S]*\(Schlafdefizit/);
   });
+
+  it("carries the v1.21.2 narrative-presence clauses (A4/A5/A6/A7)", () => {
+    expect(prompt).toMatch(/17\. Rückblick \+ Ausblick/);
+    expect(prompt).toMatch(/priorNarrative/);
+    expect(prompt).toMatch(/18\. Spannungs-Verdikt/);
+    expect(prompt).toMatch(/"TENSION"-Flag/);
+    expect(prompt).toMatch(/CLINICAL-FLOORS-OVERRIDE/);
+    expect(prompt).toMatch(/19\. Serien \+ Rückkehr zur Baseline/);
+    expect(prompt).toMatch(/wieder in deinem üblichen Bereich/i);
+    expect(prompt).toMatch(/20\. Motivational-Interviewing-Extras/);
+    expect(prompt).toMatch(/DISKREPANZ ENTWICKELN/);
+    expect(prompt).toMatch(/WIDERSTAND ANNEHMEN/);
+    expect(prompt).toMatch(/Chain-of-Ethic/);
+  });
 });
 
 /**
diff --git a/src/lib/ai/coach/derived-snapshot.ts b/src/lib/ai/coach/derived-snapshot.ts
index ad007f456..6d3fc75d1 100644
--- a/src/lib/ai/coach/derived-snapshot.ts
+++ b/src/lib/ai/coach/derived-snapshot.ts
@@ -74,17 +74,97 @@ interface CoincidentSnapshotEntry {
   illnessExplained: boolean;
 }
 
+/**
+ * v1.21.2 (A5) — the Tension Verdict flag, compactly. The readiness/recovery
+ * composite blends several contributors; when they DISAGREE (e.g. good sleep
+ * but a suppressed HRV-balance or an elevated resting pulse) the single band
+ * hides the conflict. This flag names the honest "internal read" the model
+ * narrates on the health-score card — "good sleep, but resting pulse is up — the
+ * composite lands yellow" — instead of papering the conflict over.
+ *
+ * DESCRIPTIVE multi-signal disagreement, never a cause. Computed deterministically
+ * server-side off the readiness contributors (each 0..100, higher = better); the
+ * model narrates the flag, it never invents it. Omitted entirely when the
+ * contributors agree (no tension to surface).
+ *
+ * CLINICAL-FLOORS OVERRIDE: `clinicalOverride` is true when a clinical red-flag
+ * is in play (the coincident-deviation flag fired WITHOUT an illness explanation).
+ * The narration must NOT reconcile a real red-flag away into a calm verdict — the
+ * flag carries the bit so the prompt clause can refuse the soft landing.
+ */
+interface TensionSnapshotEntry {
+  fired: true;
+  /** The composite band the disagreement resolved to (green/yellow/red). */
+  band: string;
+  /** Contributors reading FAVOURABLY, e.g. "sleep". */
+  positive: string[];
+  /** Contributors reading UNFAVOURABLY, e.g. "resting heart rate", "HRV balance". */
+  negative: string[];
+  /** True when a real clinical red-flag is in play — never reconcile it away. */
+  clinicalOverride: boolean;
+}
+
 /**
  * The derived block: per-metric compact score entries (keyed by metric id),
  * plus the optional fired-only coincident-deviation flag under its own reserved
  * `COINCIDENT_DEVIATION` key. The score entries keep their `DerivedSnapshotEntry`
  * shape (so callers + tests read `block.READINESS.value` directly); the
- * coincident flag rides alongside without widening the score index signature.
+ * coincident + tension flags ride alongside without widening the score index
+ * signature.
  */
 type DerivedSnapshotBlock = Record<string, DerivedSnapshotEntry> & {
   COINCIDENT_DEVIATION?: CoincidentSnapshotEntry;
+  TENSION?: TensionSnapshotEntry;
 };
 
+/**
+ * v1.21.2 (A5) — a contributor reading at/above this 0..100 score is FAVOURABLE;
+ * at/below `TENSION_LOW_SCORE` it is UNFAVOURABLE. The gap in the middle is
+ * "neutral" — neither side of a disagreement. A genuine tension needs at least
+ * one contributor on EACH side.
+ */
+export const TENSION_HIGH_SCORE = 70;
+export const TENSION_LOW_SCORE = 45;
+
+/** Human-readable contributor labels (no internal enum names reach the model). */
+const READINESS_CONTRIBUTOR_LABEL: Record<string, string> = {
+  rhr: "resting heart rate",
+  hrv: "HRV balance",
+  sleep: "sleep",
+  respiratory: "respiratory rate",
+  mood: "mood stability",
+};
+
+/**
+ * v1.21.2 (A5) — derive the Tension Verdict from the readiness contributors.
+ * Pure: a list of `{ key, value }` contributors (value 0..100, higher = better,
+ * null = absent) plus the composite band and the clinical-override bit. Returns
+ * the fired flag ONLY when at least one contributor reads favourably AND at least
+ * one reads unfavourably — a genuine internal disagreement. Null otherwise.
+ */
+export function deriveTension(
+  contributors: Array<{ key: string; value: number | null }>,
+  band: string | undefined,
+  clinicalOverride: boolean,
+): TensionSnapshotEntry | null {
+  const positive: string[] = [];
+  const negative: string[] = [];
+  for (const c of contributors) {
+    if (c.value === null) continue;
+    const label = READINESS_CONTRIBUTOR_LABEL[c.key] ?? c.key;
+    if (c.value >= TENSION_HIGH_SCORE) positive.push(label);
+    else if (c.value <= TENSION_LOW_SCORE) negative.push(label);
+  }
+  if (positive.length === 0 || negative.length === 0) return null;
+  return {
+    fired: true,
+    band: band ?? "yellow",
+    positive,
+    negative,
+    clinicalOverride,
+  };
+}
+
 /** Pull the headline number + band off each metric's value shape. */
 function summariseValue(
   metric: DerivedMetricId,
@@ -177,9 +257,26 @@ export async function buildDerivedSnapshotBlock(
     }),
   );
 
+  // v1.21.2 (A5) — capture the readiness contributors so the Tension Verdict can
+  // read the per-contributor directions the composite band hides. Only the
+  // readiness blend exposes them; recovery resolves to the same proxy when no
+  // device-native row exists, so reading readiness once is enough.
+  let readinessContributors: Array<{ key: string; value: number | null }> = [];
+  let readinessBand: string | undefined;
+
   for (const { metric, derived } of computed) {
     if (derived === null) continue;
     if (!isDerivedOk(derived)) continue; // omit insufficient — no noise
+    if (metric === "READINESS") {
+      const v = derived.value as {
+        band?: string;
+        components?: Array<{ key: string; value: number | null }>;
+      };
+      readinessBand = typeof v.band === "string" ? v.band : undefined;
+      readinessContributors = Array.isArray(v.components)
+        ? v.components.map((c) => ({ key: c.key, value: c.value }))
+        : [];
+    }
     const summary = summariseValue(metric, derived.value);
     if (!summary) continue;
     block[metric] = {
@@ -223,7 +320,9 @@ export async function buildDerivedSnapshotBlock(
   // own reserved key alongside the score entries.
   const out: DerivedSnapshotBlock = block;
   const coincident = await coincidentPromise;
-  if (coincident && isDerivedOk(coincident) && coincident.value.fired) {
+  const coincidentFired =
+    coincident !== null && isDerivedOk(coincident) && coincident.value.fired;
+  if (coincidentFired) {
     out.COINCIDENT_DEVIATION = {
       fired: true,
       contributing: coincident.value.contributing.map(
@@ -235,5 +334,19 @@ export async function buildDerivedSnapshotBlock(
     };
   }
 
+  // v1.21.2 (A5) — the Tension Verdict. A real clinical red-flag is in play when
+  // the coincident-deviation flag fired WITHOUT an illness explanation; the flag
+  // carries that bit so the narration never reconciles a red-flag into a calm
+  // verdict (clinical-floors override). Only attached when the contributors
+  // genuinely disagree — a coherent readiness adds no entry.
+  const clinicalOverride =
+    coincidentFired && !coincident.value.illnessExplained;
+  const tension = deriveTension(
+    readinessContributors,
+    readinessBand,
+    clinicalOverride,
+  );
+  if (tension) out.TENSION = tension;
+
   return Object.keys(out).length > 0 ? out : null;
 }
diff --git a/src/lib/ai/coach/system-prompt.ts b/src/lib/ai/coach/system-prompt.ts
index 9dd21b76d..85ce52586 100644
--- a/src/lib/ai/coach/system-prompt.ts
+++ b/src/lib/ai/coach/system-prompt.ts
@@ -241,6 +241,50 @@ GROUND RULES
     readiness is yellow, mostly the HRV-balance piece") instead of the
     band alone. Stay descriptive; the driver is an observation, not a
     diagnosis.
+17. Recall + look ahead (v1.21.2 A4). The SNAPSHOT's "memory" block MAY
+    carry a "priorNarrative" (the headline you noted at the start of the
+    prior period) and a "trendMemory" map (where each vital sat in the prior
+    period vs now). When you have one, you may open a turn with ONE brief
+    callback that recalls the prior read AND points ahead — "as I noted
+    Monday, your sleep was short; it's recovered since — worth watching
+    tonight". One callback per reply at most, always anchored to a real
+    figure or band the block carries, never a vague "last time". If the
+    block carries no recall, do not invent one — narrate only the present.
+18. Tension Verdict — narrate the honest internal read (v1.21.2 A5). The
+    "derived" block MAY carry a "TENSION" flag (fired-only) when the
+    readiness/recovery composite's contributors DISAGREE: { band, positive[],
+    negative[], clinicalOverride }. When present, surface the conflict in one
+    honest line rather than hiding it behind the band — "good sleep, but your
+    resting pulse is up, so the composite lands {band}". Name the favourable
+    and the unfavourable contributors as the user sees them, descriptively.
+    This is the moment the read feels genuinely intelligent — do not smooth it
+    into a bland "you're doing fine". CLINICAL-FLOORS OVERRIDE: when
+    "clinicalOverride" is true a real red-flag is in play — NEVER reconcile it
+    away into a calm verdict; keep the favourable contributor honest but lead
+    with the concern and the seek-care framing the safety clauses require.
+19. Streaks + return-to-baseline (v1.21.2 A6). The SNAPSHOT MAY carry a
+    "streaks" block: per metric, { inBand, streakDays, returnEvent? }. Use it
+    to actively CLOSE a worry the user might be carrying. When a "returnEvent"
+    is present ({ daysInside, priorDaysOutside, priorDirection }) the metric
+    has come BACK inside the user's own usual range after a prior run outside
+    it — say so plainly and reassuringly: "back inside your usual range after
+    last week's dip — whatever that was, it's passed". When "inBand" is true
+    with a long streak, you may affirm the steadiness ("eight steady days in
+    your range"). The band is the user's PERSONAL range, never a clinical
+    threshold; a return only fires after a genuine prior out-of-band run, so
+    trust the flag and never manufacture a "return" the block does not carry.
+20. Motivational-interviewing freebies + anti-persuasion (v1.21.2 A7).
+    Two more MI moves are available when they fit the user's OWN goal:
+    DEVELOP DISCREPANCY — gently hold up the gap between where the data sits
+    and a goal the user named, letting them feel it rather than you closing
+    it; and ROLL WITH RESISTANCE — when the user pushes back, move WITH the
+    resistance ("that's fair — what would feel workable instead?") rather than
+    arguing the point. Anti-persuasion (Chain-of-Ethic): before you nudge,
+    silently check that the change serves the user's stated goal and their
+    autonomy, not engagement, not a target you picked for them, and not
+    persuasion for its own sake. If a nudge would only serve to push, drop it
+    and reflect instead. You inform and support a decision that stays theirs;
+    you never manipulate it.
 
 DAY-LEVEL READINGS — USE THE TIMELINE
 
@@ -746,6 +790,55 @@ GRUNDREGELN
     ihn sieht ("deine Readiness ist gelb, hauptsächlich der
     HRV-Balance-Anteil") statt nur das Band. Bleib beschreibend; der
     Treiber ist eine Beobachtung, keine Diagnose.
+17. Rückblick + Ausblick (v1.21.2 A4). Der "memory"-Block des SNAPSHOT
+    kann eine "priorNarrative" (die Schlagzeile, die du zu Beginn der
+    vorigen Periode notiert hast) und eine "trendMemory"-Map (wo jeder
+    Vitalwert in der vorigen Periode lag vs. jetzt) tragen. Wenn du eine
+    hast, darfst du einen Turn mit GENAU EINEM kurzen Rückbezug eröffnen,
+    der die frühere Lesung aufruft UND nach vorn weist — "wie ich am
+    Montag anmerkte, war dein Schlaf kurz; er hat sich seither erholt —
+    heute Abend einen Blick wert". Höchstens ein Rückbezug pro Antwort,
+    immer an einer echten Zahl oder einem Band aus dem Block verankert, nie
+    ein vages "letztes Mal". Trägt der Block keine Erinnerung, erfinde keine
+    — erzähle nur die Gegenwart.
+18. Spannungs-Verdikt — die ehrliche innere Lesung (v1.21.2 A5). Der
+    "derived"-Block kann ein "TENSION"-Flag (nur bei Auslösung) tragen, wenn
+    die Beiträge des Readiness-/Erholungs-Komposits WIDERSPRECHEN: { band,
+    positive[], negative[], clinicalOverride }. Wenn vorhanden, benenne den
+    Konflikt in einer ehrlichen Zeile, statt ihn hinter dem Band zu
+    verstecken — "guter Schlaf, aber dein Ruhepuls ist erhöht, also landet
+    das Komposit bei {band}". Benenne die günstigen und die ungünstigen
+    Beiträge so, wie der Nutzer sie sieht, beschreibend. Das ist der Moment,
+    in dem die Lesung wirklich intelligent wirkt — glätte sie nicht zu einem
+    faden "dir geht's gut". CLINICAL-FLOORS-OVERRIDE: Ist "clinicalOverride"
+    true, ist ein echtes Red Flag im Spiel — versöhne es NIE zu einem ruhigen
+    Verdikt weg; halte den günstigen Beitrag ehrlich, führe aber mit der
+    Sorge und dem Abklären-lassen-Rahmen, den die Sicherheitsregeln verlangen.
+19. Serien + Rückkehr zur Baseline (v1.21.2 A6). Der SNAPSHOT kann einen
+    "streaks"-Block tragen: je Metrik { inBand, streakDays, returnEvent? }.
+    Nutze ihn, um eine Sorge des Nutzers AKTIV zu schließen. Ist ein
+    "returnEvent" vorhanden ({ daysInside, priorDaysOutside, priorDirection }),
+    ist die Metrik nach einem vorherigen Lauf außerhalb ZURÜCK in den eigenen
+    üblichen Bereich des Nutzers gekehrt — sag das klar und beruhigend:
+    "wieder in deinem üblichen Bereich nach dem Tief letzte Woche — was es auch
+    war, es ist vorbei". Ist "inBand" true mit langer Serie, darfst du die
+    Konstanz anerkennen ("acht ruhige Tage in deinem Bereich"). Der Bereich ist
+    der PERSÖNLICHE Bereich des Nutzers, nie ein klinischer Schwellwert; eine
+    Rückkehr löst nur nach einem echten vorherigen Lauf außerhalb aus —
+    vertraue dem Flag und erfinde nie eine "Rückkehr", die der Block nicht trägt.
+20. Motivational-Interviewing-Extras + Anti-Überzeugung (v1.21.2 A7). Zwei
+    weitere MI-Moves stehen bereit, wenn sie zum EIGENEN Ziel des Nutzers
+    passen: DISKREPANZ ENTWICKELN — halte behutsam die Lücke zwischen dem, wo
+    die Daten stehen, und einem vom Nutzer genannten Ziel hoch und lass ihn sie
+    spüren, statt sie für ihn zu schließen; und WIDERSTAND ANNEHMEN — zeigt der
+    Nutzer Widerstand, geh MIT ihm ("das ist fair — was würde sich stattdessen
+    machbar anfühlen?"), statt dagegen zu argumentieren. Anti-Überzeugung
+    (Chain-of-Ethic): bevor du anstößt, prüfe still, dass die Veränderung dem
+    genannten Ziel und der Autonomie des Nutzers dient — nicht der Bindung,
+    nicht einem von dir gewählten Zielwert und nicht der Überzeugung um ihrer
+    selbst willen. Würde ein Anstoß nur dem Drängen dienen, lass ihn weg und
+    spiegele stattdessen. Du informierst und unterstützt eine Entscheidung, die
+    seine bleibt; du manipulierst sie nie.
 
 TAGES-LEVEL-MESSWERTE — NUTZE DIE TIMELINE
 
diff --git a/src/lib/ai/prompts/insight-generator.ts b/src/lib/ai/prompts/insight-generator.ts
index b5c522432..047682f4b 100644
--- a/src/lib/ai/prompts/insight-generator.ts
+++ b/src/lib/ai/prompts/insight-generator.ts
@@ -40,7 +40,7 @@ import {
 } from "./shared-contracts";
 
 /** Stable identifier for the active system prompt revision. */
-export const PROMPT_VERSION = "4.29.0" as const;
+export const PROMPT_VERSION = "4.30.0" as const;
 
 /**
  * The scope-hardened insight prompt is one structural skeleton with a
diff --git a/src/lib/insights/__tests__/streak-detector.test.ts b/src/lib/insights/__tests__/streak-detector.test.ts
new file mode 100644
index 000000000..ee0448ae9
--- /dev/null
+++ b/src/lib/insights/__tests__/streak-detector.test.ts
@@ -0,0 +1,137 @@
+import { describe, it, expect } from "vitest";
+
+import {
+  detectStreak,
+  MIN_OUT_RUN,
+  type StreakPoint,
+} from "@/lib/insights/streak-detector";
+
+/**
+ * v1.21.2 (A6) — determinism pins for the streak / return-to-baseline detector.
+ *
+ * The PROSE the Coach narrates is not tested; the FLAGS are. These assert:
+ *   - an in-band streak counts consecutive in-band days,
+ *   - a calendar GAP day breaks a streak,
+ *   - a return-to-baseline event fires only after a genuine prior out-of-band
+ *     run, and never on a one-day blip,
+ *   - too little history omits rather than guesses.
+ */
+
+/** A series of N consecutive days starting at 2026-06-01, with given values. */
+function consecutive(values: number[], startDay = 1): StreakPoint[] {
+  return values.map((value, i) => ({
+    day: `2026-06-${String(startDay + i).padStart(2, "0")}`,
+    value,
+  }));
+}
+
+const IN_BAND = { low: 60, high: 80 };
+
+describe("detectStreak — in-band streak", () => {
+  it("counts consecutive in-band days back from the latest", () => {
+    // All five days sit inside [60,80].
+    const res = detectStreak(consecutive([70, 71, 69, 72, 70]), IN_BAND);
+    expect(res.latestPlacement).toBe("in");
+    expect(res.inBand).toBe(true);
+    expect(res.streakDays).toBe(5);
+    expect(res.returnEvent).toBeUndefined();
+  });
+
+  it("a calendar gap breaks the streak", () => {
+    // Days 1-3 in-band, then a gap (no day 4), then day 5 in-band. The streak
+    // counting back from day 5 is only 1 — the gap severs it.
+    const series: StreakPoint[] = [
+      { day: "2026-06-01", value: 70 },
+      { day: "2026-06-02", value: 71 },
+      { day: "2026-06-03", value: 69 },
+      // gap: no 2026-06-04
+      { day: "2026-06-05", value: 72 },
+    ];
+    const res = detectStreak(series, IN_BAND);
+    expect(res.inBand).toBe(true);
+    expect(res.streakDays).toBe(1);
+  });
+
+  it("an out-of-band streak counts only the same side", () => {
+    // Latest day is above; the prior day was below — different runs, so the
+    // streak counting back from the latest above-day is 1.
+    const res = detectStreak(consecutive([50, 95]), IN_BAND);
+    expect(res.latestPlacement).toBe("above");
+    expect(res.inBand).toBe(false);
+    expect(res.streakDays).toBe(1);
+  });
+});
+
+describe("detectStreak — return-to-baseline event", () => {
+  it("fires after a genuine prior out-of-band run", () => {
+    // Three days above the band, then three days back inside it. The latest is
+    // in-band with a settled run, preceded by an out-of-band run of 3.
+    const res = detectStreak(consecutive([95, 96, 94, 70, 71, 69]), IN_BAND);
+    expect(res.inBand).toBe(true);
+    expect(res.streakDays).toBe(3);
+    expect(res.returnEvent).toBeDefined();
+    expect(res.returnEvent).toEqual({
+      daysInside: 3,
+      priorDaysOutside: 3,
+      priorDirection: "above",
+    });
+  });
+
+  it("does not fire on a one-day blip (below MIN_OUT_RUN)", () => {
+    // A single above-band day before the in-band run is not a run to return
+    // from — MIN_OUT_RUN gates it out.
+    expect(MIN_OUT_RUN).toBe(2);
+    const res = detectStreak(consecutive([95, 70, 71, 69]), IN_BAND);
+    expect(res.inBand).toBe(true);
+    expect(res.returnEvent).toBeUndefined();
+  });
+
+  it("does not fire when a gap separates the out-of-band run from the return", () => {
+    // Out-of-band run, then a gap, then the in-band run. The return cannot
+    // bridge a missing calendar day, so no event fires.
+    const series: StreakPoint[] = [
+      { day: "2026-06-01", value: 95 },
+      { day: "2026-06-02", value: 96 },
+      // gap: no 2026-06-03
+      { day: "2026-06-04", value: 70 },
+      { day: "2026-06-05", value: 71 },
+    ];
+    const res = detectStreak(series, IN_BAND);
+    expect(res.inBand).toBe(true);
+    expect(res.returnEvent).toBeUndefined();
+  });
+
+  it("does not fire when the metric never left the band", () => {
+    const res = detectStreak(consecutive([70, 71, 69, 72]), IN_BAND);
+    expect(res.returnEvent).toBeUndefined();
+  });
+});
+
+describe("detectStreak — conservatism", () => {
+  it("omits (null placement, no event) on an empty series", () => {
+    const res = detectStreak([], IN_BAND);
+    expect(res.latestPlacement).toBeNull();
+    expect(res.streakDays).toBe(0);
+    expect(res.returnEvent).toBeUndefined();
+  });
+
+  it("builds a personal band from the series when none is supplied", () => {
+    // A long, steady run with one recent dip. The MAD band derives from the
+    // whole series; the steady days read in-band.
+    const steady = consecutive([
+      70, 71, 69, 70, 72, 68, 70, 71, 69, 70, 71, 70,
+    ]);
+    const res = detectStreak(steady);
+    expect(res.latestPlacement).toBe("in");
+    expect(res.streakDays).toBeGreaterThan(0);
+  });
+
+  it("omits when there is too little history to build a band", () => {
+    // An empty band build returns null → a quiet omit. A single point gives a
+    // zero-spread band; supplying no band and one point yields an in placement
+    // but never a return. The conservatism we pin is the empty case above; a
+    // degenerate one-point series must at least never fabricate a return.
+    const res = detectStreak(consecutive([70]));
+    expect(res.returnEvent).toBeUndefined();
+  });
+});
diff --git a/src/lib/insights/streak-detector.ts b/src/lib/insights/streak-detector.ts
new file mode 100644
index 000000000..9484b3a02
--- /dev/null
+++ b/src/lib/insights/streak-detector.ts
@@ -0,0 +1,210 @@
+/**
+ * v1.21.2 (A6) — per-metric in/out-of-band streak + return-to-baseline event.
+ *
+ * A PURE detector over a DAY-bucket per-day-mean series. It answers two
+ * questions the "ambient Coach presence" surface needs to close a worry:
+ *
+ *   1. How many consecutive days has this metric sat INSIDE (or OUTSIDE) its
+ *      personal range, counting back from the most recent day? A streak is
+ *      strictly consecutive: a calendar GAP day (a day with no reading)
+ *      BREAKS it — we never paper over a missing day as "still inside".
+ *   2. Did the metric just RETURN to its personal range after a run outside
+ *      it? "Back inside your usual range after last week's dip — whatever that
+ *      was, it's passed." A return only fires when a prior OUT-of-band run of
+ *      at least `MIN_OUT_RUN` days is followed by an IN-band run of at least
+ *      `MIN_IN_RUN` days ending on the latest day. Without a genuine prior
+ *      out-of-band run there is nothing to "return" from.
+ *
+ * The band is the user's OWN personal range: median ± k·MAD (Hampel/Leys),
+ * built by `buildBaselineBand` from the SAME series — never an invented
+ * clinical threshold. The band is established over the WHOLE series so a
+ * single recent dip doesn't move the goalposts; callers that want a stricter
+ * "prior period establishes the band" split can pass a pre-built band.
+ *
+ * Inherent-low conservatism: when the series is too short to establish a band
+ * (or the caller passes none and `buildBaselineBand` returns null), the
+ * detector returns a quiet `null`-streak result and fires NO return event —
+ * it omits rather than guesses.
+ *
+ * Pure: no DB, no clock, no network. Fully unit-testable over injected series.
+ */
+import { buildBaselineBand } from "@/lib/insights/derived/baseline";
+
+/** One DAY-bucket point: a calendar day key (YYYY-MM-DD) + that day's mean. */
+export interface StreakPoint {
+  /** Calendar day key in the user's timezone (YYYY-MM-DD). */
+  day: string;
+  /** The day's mean value. */
+  value: number;
+}
+
+/** A personal range: the median ± k·MAD band a value sits inside or outside. */
+export interface StreakBand {
+  low: number;
+  high: number;
+}
+
+/** Where a single day's value sits relative to the personal band. */
+export type BandPlacement = "in" | "above" | "below";
+
+/**
+ * Minimum consecutive out-of-band days that count as a genuine "run" the user
+ * could have worried about — a one-day blip is not a run to return from.
+ */
+export const MIN_OUT_RUN = 2;
+/** Minimum consecutive in-band days that count as a settled "return". */
+export const MIN_IN_RUN = 2;
+
+/** The detector's result: the current streak + an optional return event. */
+export interface StreakResult {
+  /**
+   * The most-recent day's placement relative to the band, or null when no
+   * band could be established (too little history).
+   */
+  latestPlacement: BandPlacement | null;
+  /**
+   * Consecutive days (counting back from the latest day) the metric held the
+   * SAME in/out state. A calendar gap breaks the count. 0 when no band.
+   */
+  streakDays: number;
+  /** True when the current streak is an INSIDE-the-band run. */
+  inBand: boolean;
+  /**
+   * The return-to-baseline event, present only when a prior out-of-band run of
+   * ≥ MIN_OUT_RUN days is followed by an in-band run of ≥ MIN_IN_RUN days
+   * ending on the latest day. Absent (undefined) otherwise — silence is the
+   * default.
+   */
+  returnEvent?: {
+    /** Days the metric has now sat back inside its range (the in-band run). */
+    daysInside: number;
+    /** Days the prior out-of-band run lasted (the dip it returned from). */
+    priorDaysOutside: number;
+    /** Which side the prior run sat on. */
+    priorDirection: Exclude<BandPlacement, "in">;
+  };
+}
+
+/** Classify one value against the personal band. */
+function placeValue(value: number, band: StreakBand): BandPlacement {
+  if (value > band.high) return "above";
+  if (value < band.low) return "below";
+  return "in";
+}
+
+/**
+ * Detect the current in/out-of-band streak and any return-to-baseline event
+ * from a DAY-bucket series.
+ *
+ * `series` need not be sorted; it is sorted ascending by day internally.
+ * Duplicate day keys are not expected (the caller passes per-day means) but a
+ * later entry for the same day wins, defensively.
+ *
+ * `band` may be supplied (e.g. a prior-period band) — when omitted it is built
+ * from the whole series via `buildBaselineBand`. A gap day (a calendar day with
+ * no point between two present days) BREAKS any streak that would span it.
+ */
+export function detectStreak(
+  series: StreakPoint[],
+  band?: StreakBand | null,
+): StreakResult {
+  const empty: StreakResult = {
+    latestPlacement: null,
+    streakDays: 0,
+    inBand: false,
+  };
+
+  // De-dupe by day (last wins) and sort ascending so "consecutive" is by date.
+  const byDay = new Map<string, number>();
+  for (const p of series) {
+    if (!Number.isFinite(p.value)) continue;
+    byDay.set(p.day, p.value);
+  }
+  const points = [...byDay.entries()]
+    .map(([day, value]) => ({ day, value }))
+    .sort((a, b) => (a.day < b.day ? -1 : 1));
+  if (points.length === 0) return empty;
+
+  // Resolve the personal band: caller-supplied, else median ± k·MAD over the
+  // whole series. Null (too little history) → omit rather than guess.
+  const resolvedBand = band ?? buildBandFromSeries(points.map((p) => p.value));
+  if (!resolvedBand) return empty;
+
+  // Per-day placement, ascending. A gap day inserts an explicit break marker so
+  // the streak walk below cannot bridge a missing calendar day.
+  const placements: BandPlacement[] = points.map((p) =>
+    placeValue(p.value, resolvedBand),
+  );
+  const days = points.map((p) => p.day);
+
+  // ── current streak: walk back from the latest day, same state, no gap ──
+  const latestPlacement = placements[placements.length - 1];
+  const latestInBand = latestPlacement === "in";
+  let streakDays = 1;
+  for (let i = placements.length - 2; i >= 0; i--) {
+    if (dayGap(days[i], days[i + 1]) !== 1) break; // calendar gap breaks it
+    const sameState =
+      (placements[i] === "in") === latestInBand &&
+      // For an out-of-band streak, require the SAME side (above vs below); a
+      // flip from above to below is a different run, not one streak.
+      (latestInBand || placements[i] === latestPlacement);
+    if (!sameState) break;
+    streakDays += 1;
+  }
+
+  const result: StreakResult = {
+    latestPlacement,
+    streakDays,
+    inBand: latestInBand,
+  };
+
+  // ── return-to-baseline event ──
+  // Only when the metric is currently IN-band with a settled in-band run, and
+  // the days IMMEDIATELY before that run (no gap) were a genuine out-of-band
+  // run of ≥ MIN_OUT_RUN days on one side.
+  if (latestInBand && streakDays >= MIN_IN_RUN) {
+    const inRunStart = placements.length - streakDays; // index of the in-run's first day
+    // The out-of-band run must be calendar-adjacent to the in-band run.
+    if (
+      inRunStart > 0 &&
+      dayGap(days[inRunStart - 1], days[inRunStart]) === 1 &&
+      placements[inRunStart - 1] !== "in"
+    ) {
+      const priorDirection = placements[inRunStart - 1] as Exclude<
+        BandPlacement,
+        "in"
+      >;
+      let priorDaysOutside = 1;
+      for (let i = inRunStart - 2; i >= 0; i--) {
+        if (dayGap(days[i], days[i + 1]) !== 1) break;
+        if (placements[i] !== priorDirection) break;
+        priorDaysOutside += 1;
+      }
+      if (priorDaysOutside >= MIN_OUT_RUN) {
+        result.returnEvent = {
+          daysInside: streakDays,
+          priorDaysOutside,
+          priorDirection,
+        };
+      }
+    }
+  }
+
+  return result;
+}
+
+/** Build the personal band from a value series; null when too little data. */
+function buildBandFromSeries(values: number[]): StreakBand | null {
+  const band = buildBaselineBand(values);
+  if (!band) return null;
+  if (!Number.isFinite(band.low) || !Number.isFinite(band.high)) return null;
+  return { low: band.low, high: band.high };
+}
+
+/** Whole-day gap between two YYYY-MM-DD keys (>=1; 1 = adjacent). */
+function dayGap(earlier: string, later: string): number {
+  const a = Date.parse(`${earlier}T00:00:00Z`);
+  const b = Date.parse(`${later}T00:00:00Z`);
+  if (Number.isNaN(a) || Number.isNaN(b)) return Number.POSITIVE_INFINITY;
+  return Math.round((b - a) / (24 * 60 * 60 * 1000));
+}