diff --git a/package.json b/package.json
index 18aa38d37..0965332cf 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "healthlog",
-  "version": "1.30.14",
+  "version": "1.30.15",
   "description": "Self-hosted personal-health-tracking PWA with Withings integration, AI insights, and doctor-report PDF export.",
   "license": "PolyForm-Noncommercial-1.0.0",
   "homepage": "https://healthlog.dev",
diff --git a/public/sw.js b/public/sw.js
index 5f5202b79..59c89043e 100644
--- a/public/sw.js
+++ b/public/sw.js
@@ -36,7 +36,7 @@ try {
 // v1.4.38.4 → v1.4.42. Do not hand-edit; bump `package.json` and rebuild.
 const CACHE_VERSION =
   (typeof self !== "undefined" && self.__APP_VERSION__) ||
-  /* @sw-version-fallback */ "v1.30.14";
+  /* @sw-version-fallback */ "v1.30.15";
 const STATIC_CACHE = `healthlog-static-${CACHE_VERSION}`;
 const PAGE_CACHE = `healthlog-pages-${CACHE_VERSION}`;
 // v1.18.6 — read-only data cache for a curated allowlist of safe GET `/api/*`
diff --git a/src/lib/ai/prompts/base-system.ts b/src/lib/ai/prompts/base-system.ts
index 6f16d1576..687bf4e03 100644
--- a/src/lib/ai/prompts/base-system.ts
+++ b/src/lib/ai/prompts/base-system.ts
@@ -303,14 +303,26 @@ export const ASSESSMENT_SECTION_PAIRS: readonly {
   de: string;
 }[] = ASSESSMENT_SECTIONS;
 
-export function getBaseSystemPrompt(locale: Locale): string {
+export function getBaseSystemPromptBody(locale: Locale): string {
   // German readers compose the German body; every other locale composes the
   // English body and is told, in its own language, which language to write in.
   // The former `locale === "en" ? "en" : "de"` sent French, Spanish, Italian
   // and Polish readers a German prompt that asked for German prose.
-  const composed = composeAssessmentPrompt(
+  return composeAssessmentPrompt(
     instructionLocale(locale),
     targetLanguageName(locale),
   );
-  return withOutputLanguage(composed, locale);
+}
+
+/**
+ * The base prompt as a STANDALONE system prompt, language directive included.
+ *
+ * Use this only when the result is handed to the provider as-is. A module that
+ * appends its own metric section must instead compose
+ * `getBaseSystemPromptBody` and wrap the finished string in
+ * `withOutputLanguage`, so the directive stays the last instruction the model
+ * reads rather than being buried mid-prompt by the appended section.
+ */
+export function getBaseSystemPrompt(locale: Locale): string {
+  return withOutputLanguage(getBaseSystemPromptBody(locale), locale);
 }
diff --git a/src/lib/ai/prompts/blood-pressure.ts b/src/lib/ai/prompts/blood-pressure.ts
index 29943d94f..0b913a55b 100644
--- a/src/lib/ai/prompts/blood-pressure.ts
+++ b/src/lib/ai/prompts/blood-pressure.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const BP_SECTION_DE = `METRIK — BLUTDRUCK:
@@ -31,9 +32,12 @@ export function getBloodPressureSystemPrompt(locale: Locale): string {
   // language and appends their own directive); only de takes the German one.
   const section =
     instructionLocale(locale) === "en" ? BP_SECTION_EN : BP_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getBloodPressureUserPrompt(
diff --git a/src/lib/ai/prompts/bmi.ts b/src/lib/ai/prompts/bmi.ts
index f8d152162..9816b1412 100644
--- a/src/lib/ai/prompts/bmi.ts
+++ b/src/lib/ai/prompts/bmi.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const BMI_SECTION_DE = `METRIK — BMI:
@@ -23,9 +24,12 @@ export function getBmiSystemPrompt(locale: Locale): string {
   // language and appends their own directive); only de takes the German one.
   const section =
     instructionLocale(locale) === "en" ? BMI_SECTION_EN : BMI_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getBmiUserPrompt(
diff --git a/src/lib/ai/prompts/general-status.ts b/src/lib/ai/prompts/general-status.ts
index 0c6677cd7..33b4755b4 100644
--- a/src/lib/ai/prompts/general-status.ts
+++ b/src/lib/ai/prompts/general-status.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const GENERAL_SECTION_DE = `METRIK — GESAMTBEWERTUNG:
@@ -27,9 +28,12 @@ export function getGeneralStatusSystemPrompt(locale: Locale): string {
     instructionLocale(locale) === "en"
       ? GENERAL_SECTION_EN
       : GENERAL_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getGeneralStatusUserPrompt(
diff --git a/src/lib/ai/prompts/medication-compliance.ts b/src/lib/ai/prompts/medication-compliance.ts
index c0983dbc0..8db71fd31 100644
--- a/src/lib/ai/prompts/medication-compliance.ts
+++ b/src/lib/ai/prompts/medication-compliance.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const MEDCO_SECTION_DE = `METRIK — MEDIKAMENTEN-EINNAHMETREUE:
@@ -25,9 +26,12 @@ export function getMedicationComplianceSystemPrompt(locale: Locale): string {
   // language and appends their own directive); only de takes the German one.
   const section =
     instructionLocale(locale) === "en" ? MEDCO_SECTION_EN : MEDCO_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getMedicationComplianceUserPrompt(
diff --git a/src/lib/ai/prompts/metric-archetypes.ts b/src/lib/ai/prompts/metric-archetypes.ts
index c8c08952c..1d8f45279 100644
--- a/src/lib/ai/prompts/metric-archetypes.ts
+++ b/src/lib/ai/prompts/metric-archetypes.ts
@@ -21,8 +21,8 @@
  * block, exactly like the specialised generators.
  */
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
-import { instructionLocale } from "./output-language";
+import { getBaseSystemPromptBody } from "./base-system";
+import { instructionLocale, withOutputLanguage } from "./output-language";
 import type {
   MetricArchetype,
   MetricStatusMeta,
@@ -110,11 +110,14 @@ export function getMetricArchetypeSystemPrompt(
   const section = ARCHETYPE_SECTION[meta.archetype];
   const archetypeText =
     instructionLocale(locale) === "en" ? section.en : section.de;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
 ${archetypeText}
 
-${metaBlock(meta, locale)}`;
+${metaBlock(meta, locale)}`,
+    locale,
+  );
 }
 
 export function getMetricArchetypeUserPrompt(
diff --git a/src/lib/ai/prompts/mood.ts b/src/lib/ai/prompts/mood.ts
index 1f0b2b672..7e10f6f37 100644
--- a/src/lib/ai/prompts/mood.ts
+++ b/src/lib/ai/prompts/mood.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const MOOD_SECTION_DE = `METRIK — STIMMUNG / WOHLBEFINDEN:
@@ -25,9 +26,12 @@ export function getMoodSystemPrompt(locale: Locale): string {
   // language and appends their own directive); only de takes the German one.
   const section =
     instructionLocale(locale) === "en" ? MOOD_SECTION_EN : MOOD_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getMoodUserPrompt(
diff --git a/src/lib/ai/prompts/pulse.ts b/src/lib/ai/prompts/pulse.ts
index 7a10338f3..5249b3164 100644
--- a/src/lib/ai/prompts/pulse.ts
+++ b/src/lib/ai/prompts/pulse.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const PULSE_SECTION_DE = `METRIK — PULS / HERZFREQUENZ:
@@ -23,9 +24,12 @@ export function getPulseSystemPrompt(locale: Locale): string {
   // language and appends their own directive); only de takes the German one.
   const section =
     instructionLocale(locale) === "en" ? PULSE_SECTION_EN : PULSE_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getPulseUserPrompt(
diff --git a/src/lib/ai/prompts/status-batch.ts b/src/lib/ai/prompts/status-batch.ts
index 2f57b3ea0..340a94f28 100644
--- a/src/lib/ai/prompts/status-batch.ts
+++ b/src/lib/ai/prompts/status-batch.ts
@@ -18,8 +18,8 @@
  * very snapshot + per-metric suffix it would have sent on its own.
  */
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
-import { instructionLocale } from "./output-language";
+import { getBaseSystemPromptBody } from "./base-system";
+import { instructionLocale, withOutputLanguage } from "./output-language";
 
 /**
  * The stable per-metric output keys the batch envelope uses. The InsightStatus
@@ -47,7 +47,7 @@ export function getStatusBatchSystemPrompt(
   locale: Locale,
   presentKeys: readonly string[],
 ): string {
-  const base = getBaseSystemPrompt(locale);
+  const base = getBaseSystemPromptBody(locale);
   const keyList = presentKeys.join(", ");
   const en = `BATCHED OUTPUT — you are assessing SEVERAL of this user's metrics in one pass. Each metric below carries its OWN graded snapshot under a "### <key>" heading; assess each one STRICTLY from its own snapshot block, applying every rule above per metric. Do NOT let one metric's finding leak into another. Do NOT invent a metric: assess ONLY the keys present below.
 
@@ -59,7 +59,10 @@ Include a key ONLY if its snapshot block is present below (keys present: ${keyLi
 AUSGABEFORMAT: Antworte ausschließlich mit validem JSON in genau diesem Schema. "perMetric" enthält je vorhandenem Key eine kurze Einschätzung (je 2-4 Sätze, derselbe Vertrag wie eine Einzelkarte):
 { "perMetric": { ${presentKeys.map((k) => `"${k}": "..."`).join(", ")} } }
 Nimm einen Key NUR auf, wenn sein Snapshot-Block unten vorhanden ist (vorhandene Keys: ${keyList}). Lass jede Metrik ohne Block weg — erfinde niemals eine.`;
-  return `${base}\n\n${instructionLocale(locale) === "en" ? en : de}`;
+  return withOutputLanguage(
+    `${base}\n\n${instructionLocale(locale) === "en" ? en : de}`,
+    locale,
+  );
 }
 
 /**
diff --git a/src/lib/ai/prompts/weight.ts b/src/lib/ai/prompts/weight.ts
index 02db48761..2ef68d7cd 100644
--- a/src/lib/ai/prompts/weight.ts
+++ b/src/lib/ai/prompts/weight.ts
@@ -1,5 +1,6 @@
 import type { Locale } from "@/lib/i18n/config";
-import { getBaseSystemPrompt } from "./base-system";
+import { getBaseSystemPromptBody } from "./base-system";
+import { withOutputLanguage } from "./output-language";
 import { instructionLocale } from "./output-language";
 
 const WEIGHT_SECTION_DE = `METRIK — GEWICHT:
@@ -29,9 +30,12 @@ export function getWeightSystemPrompt(locale: Locale): string {
   // language and appends their own directive); only de takes the German one.
   const section =
     instructionLocale(locale) === "en" ? WEIGHT_SECTION_EN : WEIGHT_SECTION_DE;
-  return `${getBaseSystemPrompt(locale)}
+  return withOutputLanguage(
+    `${getBaseSystemPromptBody(locale)}
 
-${section}`;
+${section}`,
+    locale,
+  );
 }
 
 export function getWeightUserPrompt(
diff --git a/src/lib/insights/derived/derived-assessment-ai.ts b/src/lib/insights/derived/derived-assessment-ai.ts
index 0b8dc81fb..3b142ef60 100644
--- a/src/lib/insights/derived/derived-assessment-ai.ts
+++ b/src/lib/insights/derived/derived-assessment-ai.ts
@@ -22,10 +22,14 @@
  * Server-only — reads the DB + the provider chain.
  */
 import {
-  getBaseSystemPrompt,
+  getBaseSystemPromptBody,
   PROMPT_VERSION,
 } from "@/lib/ai/prompts/base-system";
-import { instructionLocale } from "@/lib/ai/prompts/output-language";
+import type { Locale } from "@/lib/i18n/config";
+import {
+  instructionLocale,
+  withOutputLanguage,
+} from "@/lib/ai/prompts/output-language";
 import {
   normalizeLocale,
   normalizeSummaryText,
@@ -43,7 +47,6 @@ import {
 import type { MeasurementType } from "@/generated/prisma/client";
 import { resolveUserTimezone, userDayKey } from "@/lib/tz/resolver";
 import { annotate } from "@/lib/logging/context";
-import { instructionLocale } from "@/lib/ai/prompts/output-language";
 import {
   openerArchetypeHint,
   dayRotatedSeed,
@@ -98,7 +101,7 @@ const SCORE_INPUT_TYPES: readonly MeasurementType[] = [
  * the way in; today's callers still pass a narrowed locale.
  */
 function scoreSystemPrompt(locale: Locale): string {
-  const base = getBaseSystemPrompt(locale);
+  const base = getBaseSystemPromptBody(locale);
   // The archetype section rides the same reviewed instruction body the base
   // composes: German for a German reader, English for everyone else. The base
   // already names the reader's own language, so a French reader gets the
@@ -118,7 +121,7 @@ This is a daily wellness proxy, not a clinical or training-recovery verdict. Sta
 - WAS ES HEUTE BEDEUTET — übersetze das Band in einen Ausblick: ein starker Tagesform-/Erholungs-Score → ein guter Tag, um mehr zu wagen / etwas zu pushen; ein schwacher Score → ein ruhigerer Tag tut gut, nimm ihn als Erholungshinweis. Das ist eine band-bedingte Deutung, KEINE neue Zahl — erfinde dafür keine Zahl.
 - EIN ANSTOSS — schließe mit dem einen gegroundeten nächsten Schritt am schwächsten verhaltens-adressierbaren Beitrag. Ist nichts verhaltens-adressierbar (der schwache Treiber ist reine Physiologie), bestätige und nenne einen Punkt zum Beobachten, statt einen Schritt zu erfinden.
 Das ist ein täglicher Wellness-Indikator, kein klinisches Urteil und keine Trainings-Recovery-Bewertung. Bleibe beschreibend, nie diagnostisch, nie alarmierend; die Ermutigung ist durch die Beiträge / den Trend verdient, nie ein reflexhaftes Kompliment und nie bloße Zahlenwiederholung.`;
-  return `${base}\n\n${section}`;
+  return withOutputLanguage(`${base}\n\n${section}`, locale);
 }
 
 function scoreUserPrompt(