feat(coach): default analysis window as user preference + per-conversation override

`coachPrefs.defaultWindow` joins the existing prefs blob (tone,
verbosity, excludeMetrics, showEvidenceByDefault). The picker lives in
the Coach settings sheet; the drawer header carries a small pill that
overrides the saved default for the current chat only. Closing the
drawer drops the override so the next session starts on the saved
preference. Backwards-compatible: legacy rows missing the key resolve
to "allTime", matching the v1.4.24 behaviour. The chat route folds the
saved window into snapshot scope when the client doesn't supply one.

src/app/api/insights/chat/route.ts

@@ -206,12 +206,22 @@ async function handleChatRequest(request: NextRequest): Promise<Response> {
   // the new user message. v1.4.23 H4 — fold per-user prefs into the
   // system-prompt prefix; the snapshot builder reads the same prefs
   // separately so excluded metrics never even leave the DB.
+  //
+  // v1.4.25 W5 — `coachPrefs.defaultWindow` is the user's saved
+  // analysis-window preference. Merge it into the snapshot scope when
+  // the client didn't supply a per-conversation override; the override
+  // (header pill / sources rail) always wins. Keep the merge cheap so
+  // we don't accidentally widen narrow per-call scopes.
   const prefsRow = await prisma.user.findUnique({
     where: { id: userId },
     select: { coachPrefsJson: true },
   });
   const coachPrefs = parseCoachPrefs(prefsRow?.coachPrefsJson);
-  const snapshot = await buildCoachSnapshot(userId, scope);
+  const effectiveScope =
+    scope?.window === undefined && coachPrefs.defaultWindow
+      ? { ...(scope ?? {}), window: coachPrefs.defaultWindow }
+      : scope;
+  const snapshot = await buildCoachSnapshot(userId, effectiveScope);
   const systemPrompt = getCoachSystemPrompt(locale, coachPrefs);
   const window = buildHistoryWindow([
     ...priorTurns,

src/components/insights/coach-panel/__tests__/coach-settings-sheet.test.tsx

@@ -104,4 +104,14 @@ describe("<CoachSettingsSheet>", () => {
     expect(vi.mocked(toast.success)).toHaveBeenCalledTimes(1);
     expect(vi.mocked(toast.success)).toHaveBeenCalledWith("Saved.");
   });
+
+  // v1.4.25 W5 — defaultWindow picker added.
+  it("renders the default-window picker once persisted prefs land", () => {
+    queryState.data = DEFAULT_COACH_PREFS;
+    const html = render(
+      <CoachSettingsSheet open={true} onOpenChange={() => {}} />,
+    );
+    expect(html).toContain('data-slot="coach-prefs-default-window"');
+    expect(html).toContain("Default analysis window");
+  });
 });

src/components/insights/coach-panel/coach-drawer.tsx

@@ -5,6 +5,13 @@ import type { Dispatch, SetStateAction } from "react";
 import { Plus, Settings, Sparkles } from "lucide-react";
 
 import { Button } from "@/components/ui/button";
+import {
+  Select,
+  SelectContent,
+  SelectItem,
+  SelectTrigger,
+  SelectValue,
+} from "@/components/ui/select";
 import {
   Sheet,
   SheetContent,
@@ -14,6 +21,7 @@ import {
 } from "@/components/ui/sheet";
 import { cn } from "@/lib/utils";
 import { useTranslations } from "@/lib/i18n/context";
+import { useCoachPrefs } from "@/hooks/use-coach-prefs";
 
 import { CoachDrawerBody } from "./coach-drawer-body";
 import { CoachInput } from "./coach-input";
@@ -153,6 +161,13 @@ export function CoachDrawer({
   // selector). Resets to the all-source last30days default each time
   // the drawer mounts; no conversation-level persistence in this
   // hotfix per the v1.4.20.1 plan.
+  //
+  // v1.4.25 W5 — the scope.window field is now a two-layer override:
+  //   • the user's saved `coachPrefs.defaultWindow` is the base
+  //   • the header pill drops a per-conversation override into
+  //     `windowOverride`; null = "use the saved default"
+  // The override resets to null on drawer close so the next session
+  // starts on the user's saved preference.
   const [scope, setScope] = useState<{
     sources: CoachScopeSource[];
     window: CoachScopeWindow;
@@ -160,15 +175,31 @@ export function CoachDrawer({
     sources: [...DEFAULT_COACH_SCOPE.sources],
     window: DEFAULT_COACH_SCOPE.window,
   }));
+  const [windowOverride, setWindowOverride] =
+    useState<CoachScopeWindow | null>(null);
+
+  // v1.4.25 W5 — load the user's saved Coach prefs so the default
+  // window picks up the cog's saved selection. The hook gates the
+  // fetch on `enabled` so the network call only fires while the
+  // drawer is open. Falls through to the legacy "last30days" default
+  // when the row is missing or the request is in flight.
+  const { data: coachPrefs } = useCoachPrefs({ enabled: open });
+  const savedDefaultWindow: CoachScopeWindow =
+    coachPrefs?.defaultWindow ?? DEFAULT_COACH_SCOPE.window;
+  const effectiveWindow: CoachScopeWindow =
+    windowOverride ?? savedDefaultWindow;
 
   const handleOpenChange = useCallback(
     (next: boolean) => {
       if (!next) {
         // Reset thread + composer on close so the next open starts on
         // the rail's empty hint instead of re-rendering the previous
-        // conversation by accident.
+        // conversation by accident. v1.4.25 W5 — also drop the
+        // per-conversation window override so the next session starts
+        // on the user's saved `coachPrefs.defaultWindow` again.
         setCurrentConversationId(null);
         setInputValue("");
+        setWindowOverride(null);
       }
       onOpenChange(next);
     },
@@ -189,15 +220,21 @@ export function CoachDrawer({
     // Pass the scope only when the user has narrowed it from the
     // defaults — keeps the wire payload minimal and lets the route
     // tell "no opinion" apart from "intentionally narrow".
-    const isDefault =
-      scope.window === DEFAULT_COACH_SCOPE.window &&
+    //
+    // v1.4.25 W5 — `scope.window` now reflects the per-conversation
+    // override (header pill / rail picker) layered on top of the saved
+    // `coachPrefs.defaultWindow`. Send the override only when the user
+    // explicitly diverged from the saved default; otherwise the route
+    // re-applies the saved preference itself.
+    const allSourcesSelected =
       scope.sources.length === DEFAULT_COACH_SCOPE.sources.length &&
       DEFAULT_COACH_SCOPE.sources.every((s) => scope.sources.includes(s));
+    const isDefault = allSourcesSelected && windowOverride === null;
     const scopePayload: CoachScope | undefined = isDefault
       ? undefined
       : {
           sources: scope.sources,
-          window: scope.window,
+          window: effectiveWindow,
         };
     await send.send({
       conversationId: currentConversationId ?? undefined,
@@ -256,6 +293,49 @@ export function CoachDrawer({
               {t("insights.coach.tagline")}
             </SheetDescription>
           </div>
+          {/* v1.4.25 W5 — per-conversation window override. The pill
+              defaults to the user's saved `coachPrefs.defaultWindow`
+              and resets to it on drawer close. Changing the pill flips
+              `windowOverride`; the rail's window picker mirrors the
+              same source-of-truth so the user can drive the override
+              from either surface. */}
+          <Select
+            value={effectiveWindow}
+            onValueChange={(value) => {
+              const next = value as CoachScopeWindow;
+              setWindowOverride(next === savedDefaultWindow ? null : next);
+            }}
+          >
+            <SelectTrigger
+              data-slot="coach-drawer-window-pill"
+              aria-label={t("insights.coach.windowLabel")}
+              size="sm"
+              className={cn(
+                "border-border/60 bg-muted/40 text-foreground h-7 shrink-0 gap-1 rounded-full px-2.5 text-[11px]",
+                "hover:bg-muted/60 focus-visible:ring-ring/40 focus-visible:ring-2",
+                windowOverride !== null &&
+                  "border-dracula-purple/40 bg-dracula-purple/10 text-dracula-purple",
+              )}
+            >
+              <SelectValue
+                placeholder={t(`insights.coach.window.${effectiveWindow}`)}
+              />
+            </SelectTrigger>
+            <SelectContent align="end">
+              <SelectItem value="last7days" className="text-xs">
+                {t("insights.coach.window.last7days")}
+              </SelectItem>
+              <SelectItem value="last30days" className="text-xs">
+                {t("insights.coach.window.last30days")}
+              </SelectItem>
+              <SelectItem value="last90days" className="text-xs">
+                {t("insights.coach.window.last90days")}
+              </SelectItem>
+              <SelectItem value="allTime" className="text-xs">
+                {t("insights.coach.window.allTime")}
+              </SelectItem>
+            </SelectContent>
+          </Select>
           <Button
             type="button"
             variant="ghost"
@@ -297,7 +377,20 @@ export function CoachDrawer({
           }
           sourcesRail={
             sourcesRail ?? (
-              <SourcesRail scope={scope} onScopeChange={setScope} />
+              <SourcesRail
+                // v1.4.25 W5 — overlay the effective window on the rail
+                // so the picker mirrors the per-conversation override
+                // (or the saved default when no override is active).
+                // The rail's own onChange flips `windowOverride` so the
+                // rail picker is just another way to set the override.
+                scope={{ sources: scope.sources, window: effectiveWindow }}
+                onScopeChange={(next) => {
+                  setScope((prev) => ({ ...prev, sources: next.sources }));
+                  setWindowOverride(
+                    next.window === savedDefaultWindow ? null : next.window,
+                  );
+                }}
+              />
             )
           }
           thread={
@@ -374,7 +467,18 @@ export function CoachDrawer({
             </SheetHeader>
             <div className="h-full min-h-0 overflow-y-auto">
               {sourcesRail ?? (
-                <SourcesRail scope={scope} onScopeChange={setScope} />
+                <SourcesRail
+                  scope={{
+                    sources: scope.sources,
+                    window: effectiveWindow,
+                  }}
+                  onScopeChange={(next) => {
+                    setScope((prev) => ({ ...prev, sources: next.sources }));
+                    setWindowOverride(
+                      next.window === savedDefaultWindow ? null : next.window,
+                    );
+                  }}
+                />
               )}
             </div>
           </SheetContent>

src/components/insights/coach-panel/coach-settings-sheet.tsx

@@ -27,6 +27,7 @@ import { useTranslations } from "@/lib/i18n/context";
 import { useCoachPrefs } from "@/hooks/use-coach-prefs";
 import {
   DEFAULT_COACH_PREFS,
+  type CoachDefaultWindow,
   type CoachExcludeMetric,
   type CoachPrefs,
   type CoachTone,
@@ -71,6 +72,16 @@ const EXCLUDE_OPTIONS: CoachExcludeMetric[] = [
   "steps",
 ];
 
+// v1.4.25 W5 — picker options for the new `defaultWindow` preference.
+// Mirrors `CoachScopeWindow` so the chat route can fold the selection
+// straight into `scope.window` when the client didn't supply one.
+const DEFAULT_WINDOW_OPTIONS: CoachDefaultWindow[] = [
+  "last7days",
+  "last30days",
+  "last90days",
+  "allTime",
+];
+
 export function CoachSettingsSheet({
   open,
   onOpenChange,
@@ -237,6 +248,46 @@ export function CoachSettingsSheet({
               </Select>
             </div>
 
+            {/* v1.4.25 W5 — default analysis window. Sets the snapshot
+                scope window the Coach reads when the client doesn't
+                supply a per-conversation override. The drawer header
+                carries a small pill that overrides the picked default
+                for the current chat only. */}
+            <div className="flex flex-col gap-2">
+              <Label
+                htmlFor="coach-prefs-default-window"
+                className="text-xs font-medium"
+              >
+                {t("insights.coach.settingsDefaultWindowLabel")}
+              </Label>
+              <p className="text-muted-foreground text-[11px] leading-relaxed">
+                {t("insights.coach.settingsDefaultWindowHint")}
+              </p>
+              <Select
+                value={draft.defaultWindow}
+                onValueChange={(value) =>
+                  setDraft((prev) => ({
+                    ...prev,
+                    defaultWindow: value as CoachDefaultWindow,
+                  }))
+                }
+              >
+                <SelectTrigger
+                  id="coach-prefs-default-window"
+                  data-slot="coach-prefs-default-window"
+                >
+                  <SelectValue />
+                </SelectTrigger>
+                <SelectContent>
+                  {DEFAULT_WINDOW_OPTIONS.map((w) => (
+                    <SelectItem key={w} value={w}>
+                      {t(`insights.coach.window.${w}`)}
+                    </SelectItem>
+                  ))}
+                </SelectContent>
+              </Select>
+            </div>
+
             {/* Exclude metrics */}
             <div className="flex flex-col gap-2">
               <Label className="text-xs font-medium">

src/components/insights/daily-briefing.tsx

@@ -86,6 +86,11 @@ const METRIC_ICON: Record<
   distance: Route,
   vo2_max: Zap,
   body_temp: Thermometer,
+  // ── v1.4.25 W4d GLP-1 additive ──
+  // Plateau finding inherits the Pill icon since it's an
+  // adherence-context observation about the user's GLP-1 therapy.
+  // Non-GLP-1 accounts never see this finding type.
+  glp1_plateau: Pill,
 };
 
 const TONE_BAR_CLASSNAME: Record<DailyBriefingKeyFinding["tone"], string> = {

src/lib/ai/coach/system-prompt.ts

@@ -96,6 +96,31 @@ GROUND RULES
    last90days / allTime) — the ban applies to the metric label
    itself, not to the contract-level "window" token.
 
+9. NEVER prescribe, recommend, or modify medication doses
+   (v1.4.25 W4d). The SNAPSHOT may carry a "weeklyContext.glp1"
+   block that names the user's GLP-1 receptor agonist (Mounjaro,
+   Ozempic, Wegovy, Zepbound, Trulicity, Saxenda, Rybelsus), the
+   current dose, the titration history, the injection cadence, the
+   last + next injection date, the side-effect tag counts, and the
+   pen inventory. Use this block to GROUND your reply — say
+   "your Mounjaro 7.5 mg" instead of "your medication", and
+   reference "the typical Eli Lilly titration schedule waits at
+   least 4 weeks per step" when the user asks how titration
+   normally works.
+   But: when the user asks "should I increase my dose?", "is it
+   time to step up?", "can I skip a dose?", "should I stop?", or
+   any variation on dose recommendation, defer to their
+   prescribing clinician in one short sentence and offer to think
+   through the timing question with them. NEVER recommend a
+   specific value. NEVER tell them to take an action with their
+   medication. Pattern: "Dose changes are a conversation for your
+   prescribing doctor — they know the rest of your picture. If
+   it's useful, I can pull up how the last few weeks have looked
+   so you can take that into the appointment."
+   This is a SAFETY contract, not a stylistic preference. If you
+   are unsure whether a question is dose-prescriptive, treat it as
+   if it is and defer to the clinician.
+
 DAY-LEVEL READINGS — USE THE TIMELINE
 
 Each metric in the SNAPSHOT carries a "timeline" object alongside
@@ -285,6 +310,33 @@ GRUNDREGELN
    allTime) — das Verbot gilt der Metrik-Bezeichnung selbst, nicht
    dem Vertragstoken im "window"-Slot.
 
+9. Du verschreibst, empfiehlst und veränderst NIEMALS Medikamenten-
+   Dosen (v1.4.25 W4d). Der SNAPSHOT kann einen Block
+   "weeklyContext.glp1" mitbringen, der den GLP-1-Rezeptoragonisten
+   des Nutzers benennt (Mounjaro, Ozempic, Wegovy, Zepbound,
+   Trulicity, Saxenda, Rybelsus), die aktuelle Dosis, die
+   Titrationshistorie, die Injektionsfrequenz, das letzte und
+   nächste Injektionsdatum, die Nebenwirkungs-Tag-Zählungen und
+   den Pen-Bestand. Nutze diesen Block, um deine Antwort zu
+   ERDEN — sag "dein Mounjaro 7,5 mg" statt "deine Medikation",
+   und verweise auf "Eli Lillys publizierter Titrationsplan sieht
+   typischerweise mindestens 4 Wochen pro Stufe vor", wenn der
+   Nutzer fragt, wie Titration üblicherweise abläuft.
+   Aber: Wenn der Nutzer fragt "Soll ich meine Dosis erhöhen?",
+   "Ist es Zeit für die nächste Stufe?", "Kann ich eine Dosis
+   auslassen?", "Soll ich aufhören?" oder eine Variante davon
+   stellt, verweise in einem kurzen Satz an die behandelnde Ärztin
+   bzw. den Arzt und biete an, die Frage gemeinsam für den
+   nächsten Termin vorzubereiten. Empfehle NIE einen konkreten
+   Wert. Sag NIE, sie sollen etwas an ihrer Medikation ändern.
+   Muster: "Dosis-Anpassungen gehören in das Gespräch mit deiner
+   behandelnden Ärztin — sie kennt das Gesamtbild. Wenn es hilft,
+   kann ich die letzten Wochen mit dir kurz durchgehen, damit du
+   das gut vorbereitet in den Termin nimmst."
+   Das ist ein SICHERHEITS-Vertrag, kein Stil-Wunsch. Bist du
+   unsicher, ob eine Frage dosis-präskriptiv ist, behandle sie so —
+   und verweise an die Klinik.
+
 TAGES-LEVEL-MESSWERTE — NUTZE DIE TIMELINE
 
 Jede Metrik im SNAPSHOT trägt neben dem "aggregate"-Block ein

src/lib/ai/prompts/insight-generator.ts

@@ -27,7 +27,7 @@ import {
 } from "../medical-references";
 
 /** Stable identifier for the active system prompt revision. */
-export const PROMPT_VERSION = "4.24.0" as const;
+export const PROMPT_VERSION = "4.25.0" as const;
 
 const SYSTEM_PROMPT_EN = `You are a clinical-context summariser for a personal health-log app.
 Prompt version: ${PROMPT_VERSION}.
@@ -210,6 +210,21 @@ GROUND RULES — ZERO HALLUCINATIONS
     contract-level identifiers the parser reads — those stay in
     the documented enum vocabulary exactly as listed in OUTPUT
     FORMAT below. The ban applies ONLY to prose.
+14. v1.4.25 W4d — NEVER prescribe or modify medication doses, even
+    when the snapshot reveals a named GLP-1 receptor agonist
+    (Mounjaro, Ozempic, Wegovy, Zepbound, Trulicity, Saxenda,
+    Rybelsus). Findings may NOTE the named medication and the
+    user's current titration step ("week 3 on 7.5 mg") when the
+    "weeklyContext.glp1" block carries it, but recommendations and
+    summary text must NEVER read "you should step up to X mg",
+    "consider increasing to Y mg", "stop at Z mg", or any
+    variation. A plateau finding ALWAYS frames the next decision
+    as a conversation with the prescribing clinician — pattern:
+    "Weight has settled around <kg> for three weeks at <dose> —
+    typical mid-titration. Worth mentioning at the next visit if
+    it persists." This is a SAFETY contract; treat any
+    dose-prescriptive instinct as a sign the response is
+    out-of-bounds.
 
 GUIDELINE TARGETS — generic, do NOT compute precise risk scores
 - Adult resting blood pressure (ESH/ESC 2024 generic): aim < 140/90
@@ -527,6 +542,23 @@ GRUNDREGELN — NULL HALLUZINATIONEN
     Parser liest — diese bleiben EXAKT in der unten in
     AUSGABEFORMAT dokumentierten Enum-Schreibweise. Das Verbot
     gilt AUSSCHLIEßLICH für Fließtext.
+14. v1.4.25 W4d — Du verschreibst und änderst NIEMALS
+    Medikamenten-Dosen, auch wenn der Snapshot einen
+    GLP-1-Rezeptoragonisten namentlich benennt (Mounjaro, Ozempic,
+    Wegovy, Zepbound, Trulicity, Saxenda, Rybelsus). Befunde dürfen
+    den benannten Wirkstoff und die aktuelle Titrationsstufe
+    ZITIEREN ("Woche 3 auf 7,5 mg"), wenn der Block
+    "weeklyContext.glp1" diese Informationen mitbringt — aber
+    Empfehlungen und summary-Text dürfen NIEMALS "du solltest auf
+    X mg erhöhen", "erwäge die nächste Stufe Y mg", "bleibe auf Z
+    mg" oder eine Variante davon enthalten. Ein Plateau-Befund
+    rahmt die nächste Entscheidung IMMER als Gespräch mit der
+    behandelnden Ärztin — Muster: "Das Gewicht hat sich seit drei
+    Wochen bei <kg> auf <Dosis> eingependelt — typische
+    mid-titration Phase. Lohnt sich beim nächsten Termin
+    anzusprechen, falls es darüber hinaus persistiert." Das ist
+    ein SICHERHEITS-Vertrag; behandle jeden dosis-präskriptiven
+    Impuls als Signal, dass die Antwort außerhalb des Skopus liegt.
 
 LEITLINIEN-ZIELWERTE — generisch, KEINE genauen Risiko-Scores berechnen
 - Erwachsenen-Ruheblutdruck (ESH/ESC 2024 generisch): Ziel < 140/90

src/lib/ai/schema.ts

@@ -282,6 +282,13 @@ export const dailyBriefingKeyFindingSchema = z.object({
     "distance",
     "vo2_max",
     "body_temp",
+    // ── v1.4.25 W4d GLP-1 additive ──
+    // Findings emitted by the plateau-detection rule when a user has
+    // an active GLP-1 receptor agonist and weight has flattened on a
+    // stable dose for ≥21 days. The finding ALWAYS defers to the
+    // user's clinician (no dose recommendation); the enum value
+    // exists so the UI can pin the right icon + filter.
+    "glp1_plateau",
   ]),
 });
 

src/lib/validations/__tests__/coach-prefs.test.ts

@@ -21,11 +21,24 @@ describe("coachPrefsSchema", () => {
       verbosity: "brief" as const,
       excludeMetrics: ["bp", "weight"] as const,
       showEvidenceByDefault: true,
+      defaultWindow: "last30days" as const,
     };
     const out = coachPrefsSchema.parse(input);
     expect(out).toEqual(input);
   });
 
+  // v1.4.25 W5 — defaultWindow added. Missing key → fallback to
+  // "allTime" so the legacy persisted shape stays representative.
+  it("fills in defaultWindow=allTime when the key is missing", () => {
+    const out = coachPrefsSchema.parse({});
+    expect(out.defaultWindow).toBe("allTime");
+  });
+
+  it("rejects unknown defaultWindow values", () => {
+    const result = coachPrefsSchema.safeParse({ defaultWindow: "lifetime" });
+    expect(result.success).toBe(false);
+  });
+
   it("rejects unknown tone values", () => {
     const result = coachPrefsSchema.safeParse({ tone: "stoic" });
     expect(result.success).toBe(false);
@@ -82,7 +95,21 @@ describe("parseCoachPrefs", () => {
       verbosity: "default" as const,
       excludeMetrics: ["mood" as const],
       showEvidenceByDefault: true,
+      defaultWindow: "last90days" as const,
     };
     expect(parseCoachPrefs(input)).toEqual(input);
   });
+
+  it("fills defaultWindow=allTime when older persisted rows are missing it", () => {
+    // Legacy v1.4.23/v1.4.24 persisted shape without `defaultWindow`.
+    // Defaulting is backwards-compatible — the row keeps reading as
+    // "all time" until the user picks a tighter default in the cog.
+    const legacy = {
+      tone: "warm" as const,
+      verbosity: "default" as const,
+      excludeMetrics: [] as const,
+      showEvidenceByDefault: false,
+    };
+    expect(parseCoachPrefs(legacy).defaultWindow).toBe("allTime");
+  });
 });

src/lib/validations/coach-prefs.ts

@@ -7,6 +7,12 @@
  * snapshot builder both read this shape — the snapshot must filter on
  * `excludeMetrics` BEFORE landing in the system prompt so the model
  * never sees data the user opted out of.
+ *
+ * v1.4.25 W5 — extended with `defaultWindow`. The picker lives in the
+ * settings sheet; the drawer header carries a per-conversation override
+ * pill so a single chat can narrow the window without flipping the
+ * global default. The chat route folds the saved preference into the
+ * snapshot scope when the client didn't supply a window override.
  */
 import { z } from "zod/v4";
 
@@ -52,6 +58,23 @@ export const coachExcludeMetricEnum = z.enum([
 ]);
 export type CoachExcludeMetric = z.infer<typeof coachExcludeMetricEnum>;
 
+/**
+ * v1.4.25 W5 — default analysis window the Coach uses when the client
+ * doesn't supply a per-conversation override. Mirrors
+ * `CoachScopeWindow` (`src/lib/ai/coach/types.ts`) so the chat route
+ * can fold the preference into `scope.window` without a translation
+ * layer. The default stays `allTime` to preserve the v1.4.24 behaviour
+ * — every legacy row reads as "no opinion" until the user explicitly
+ * picks a tighter default.
+ */
+export const coachDefaultWindowEnum = z.enum([
+  "last7days",
+  "last30days",
+  "last90days",
+  "allTime",
+]);
+export type CoachDefaultWindow = z.infer<typeof coachDefaultWindowEnum>;
+
 /**
  * Full preferences shape. Defaults are inlined into the schema so a
  * `safeParse({})` call returns the legacy v1.4.22 defaults — saves a
@@ -62,6 +85,7 @@ export const coachPrefsSchema = z.object({
   verbosity: coachVerbosityEnum.default("default"),
   excludeMetrics: z.array(coachExcludeMetricEnum).max(9).default([]),
   showEvidenceByDefault: z.boolean().default(false),
+  defaultWindow: coachDefaultWindowEnum.default("allTime"),
 });
 
 export type CoachPrefs = z.infer<typeof coachPrefsSchema>;
@@ -77,6 +101,7 @@ export const DEFAULT_COACH_PREFS: CoachPrefs = {
   verbosity: "default",
   excludeMetrics: [],
   showEvidenceByDefault: false,
+  defaultWindow: "allTime",
 };
 
 /**