diff --git a/docs/api/openapi.yaml b/docs/api/openapi.yaml
index 88bc29ec8..e8dc5bb0a 100644
--- a/docs/api/openapi.yaml
+++ b/docs/api/openapi.yaml
@@ -2103,6 +2103,8 @@ paths:
               - PAIN_NRS
               - WAIST_CIRCUMFERENCE
               - WAIST_TO_HEIGHT
+              - WHO5_SCORE
+              - SCI_SCORE
         - in: query
           name: from
           schema:
@@ -2299,6 +2301,8 @@ paths:
                     - PAIN_NRS
                     - WAIST_CIRCUMFERENCE
                     - WAIST_TO_HEIGHT
+                    - WHO5_SCORE
+                    - SCI_SCORE
                 value:
                   type: number
                 measuredAt:
@@ -5865,6 +5869,8 @@ paths:
               - PAIN_NRS
               - WAIST_CIRCUMFERENCE
               - WAIST_TO_HEIGHT
+              - WHO5_SCORE
+              - SCI_SCORE
             description: "The measurement type to read (single metric — no fan-out). Closed enum: an unknown type 422s."
           required: true
           description: "The measurement type to read (single metric — no fan-out). Closed enum: an unknown type 422s."
@@ -8103,8 +8109,8 @@ paths:
       tags:
         - Mental health
       summary: List the caller's screener history
-      description: Returns PHQ-9 / GAD-7 administrations (newest first). Totals + bands + flags only; raw item answers are
-        never returned.
+      description: Returns PHQ-9 / GAD-7 / WHO-5 / SCI administrations (newest first). Totals + bands + flags only; raw item
+        answers are never returned.
       parameters:
         - in: query
           name: instrument
@@ -8113,6 +8119,8 @@ paths:
             enum:
               - PHQ9
               - GAD7
+              - WHO5
+              - SCI
         - in: query
           name: limit
           schema:
@@ -8138,10 +8146,11 @@ paths:
     post:
       tags:
         - Mental health
-      summary: Record a completed PHQ-9 / GAD-7 screener
+      summary: Record a completed screener
       description: Stores one administration (item answers encrypted) and writes the derived total as a server-owned
-        PHQ9_SCORE / GAD7_SCORE measurement (source COMPUTED — never client-writable). On a positive PHQ-9 item-9 the
-        response carries the locale-aware crisis-resource set.
+        PHQ9_SCORE / GAD7_SCORE / WHO5_SCORE / SCI_SCORE measurement (source COMPUTED — never client-writable). WHO-5
+        and SCI totals run HIGHER = better; their follow-up thresholds point downwards (≤ 50 / ≤ 16). On a positive
+        PHQ-9 item-9 the response carries the locale-aware crisis-resource set.
       requestBody:
         content:
           application/json:
@@ -8153,6 +8162,8 @@ paths:
                   enum:
                     - PHQ9
                     - GAD7
+                    - WHO5
+                    - SCI
                 items:
                   minItems: 1
                   maxItems: 12
@@ -8160,7 +8171,7 @@ paths:
                   items:
                     type: integer
                     minimum: 0
-                    maximum: 3
+                    maximum: 5
                 functionalDifficulty:
                   type: integer
                   minimum: 0
@@ -11145,9 +11156,11 @@ components:
         - BODY_MASS_INDEX
         - PHQ9_SCORE
         - GAD7_SCORE
-      description: Auto-resolve target metric (vitals + body-composition family + the PHQ-9 / GAD-7 screenings). BP resolves
-        on BLOOD_PRESSURE_SYS (the SYS row is the 'a BP was measured' sentinel); a screening reminder resolves on the
-        server-written PHQ9_SCORE / GAD7_SCORE row when a check-in completes. Omit for a free-text Vorsorge that
+        - WHO5_SCORE
+        - SCI_SCORE
+      description: Auto-resolve target metric (vitals + body-composition family + the PHQ-9 / GAD-7 / WHO-5 / SCI screenings).
+        BP resolves on BLOOD_PRESSURE_SYS (the SYS row is the 'a BP was measured' sentinel); a screening reminder
+        resolves on the server-written *_SCORE row when a check-in completes. Omit for a free-text Vorsorge that
         resolves only on a manual satisfy or a matching lab result.
     MeasurementReminderUpdate:
       type: object
@@ -13904,6 +13917,8 @@ components:
             - PAIN_NRS
             - WAIST_CIRCUMFERENCE
             - WAIST_TO_HEIGHT
+            - WHO5_SCORE
+            - SCI_SCORE
         value:
           type: number
         unit:
@@ -14227,6 +14242,8 @@ components:
               - PAIN_NRS
               - WAIST_CIRCUMFERENCE
               - WAIST_TO_HEIGHT
+              - WHO5_SCORE
+              - SCI_SCORE
           additionalProperties:
             type: array
             items:
@@ -14310,6 +14327,8 @@ components:
                     - PAIN_NRS
                     - WAIST_CIRCUMFERENCE
                     - WAIST_TO_HEIGHT
+                    - WHO5_SCORE
+                    - SCI_SCORE
                 value:
                   type: number
                   description: Daily mean (spot metrics) or SUM (cumulative).
@@ -14414,6 +14433,8 @@ components:
             - PAIN_NRS
             - WAIST_CIRCUMFERENCE
             - WAIST_TO_HEIGHT
+            - WHO5_SCORE
+            - SCI_SCORE
           description: Per-type daily series, keyed by MeasurementType.
       required:
         - series
@@ -14653,6 +14674,8 @@ components:
             - PAIN_NRS
             - WAIST_CIRCUMFERENCE
             - WAIST_TO_HEIGHT
+            - WHO5_SCORE
+            - SCI_SCORE
         value:
           type: number
         unit:
@@ -25212,6 +25235,8 @@ components:
           enum:
             - PHQ9
             - GAD7
+            - WHO5
+            - SCI
         locale:
           type: string
         version:
diff --git a/prisma/migrations/0226_v1279_screening_scores/migration.sql b/prisma/migrations/0226_v1279_screening_scores/migration.sql
new file mode 100644
index 000000000..ab9f6f77b
--- /dev/null
+++ b/prisma/migrations/0226_v1279_screening_scores/migration.sql
@@ -0,0 +1,15 @@
+-- v1.27.9 — screening-score enum values for the two new self-report
+-- instruments: the WHO-5 well-being index (percentage 0–100, raw sum × 4)
+-- and the Sleep Condition Indicator (total 0–32, higher = better sleep).
+--
+-- Same contract as PHQ9_SCORE / GAD7_SCORE (0213/0225 lineage): the value is
+-- server-derived from a completed MentalHealthAssessment and written as a
+-- `COMPUTED`-source Measurement row, so clients can never forge a trend point
+-- through the measurement write surfaces. Additive, idempotent.
+ALTER TYPE "measurement_type" ADD VALUE IF NOT EXISTS 'WHO5_SCORE';
+ALTER TYPE "measurement_type" ADD VALUE IF NOT EXISTS 'SCI_SCORE';
+
+-- The assessment discriminator learns the two new instruments (0213 created
+-- it with PHQ9/GAD7 only).
+ALTER TYPE "assessment_instrument" ADD VALUE IF NOT EXISTS 'WHO5';
+ALTER TYPE "assessment_instrument" ADD VALUE IF NOT EXISTS 'SCI';
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index 4c25019fb..a4f69bf9c 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -1284,17 +1284,26 @@ enum MeasurementType {
   // waist-to-height ratio (WHtR; keep waist < half your height ⇒ < 0.5).
   WAIST_CIRCUMFERENCE // cm — waist circumference (WHO bands; ethnicity-aware at display).
   WAIST_TO_HEIGHT // ratio — waist-to-height ratio (WHtR ≥ 0.5 = increased risk).
+  // ── v1.27.9 — screening scores (WHO-5 well-being + Sleep Condition Indicator) ──
+  // Same contract as PHQ9_SCORE / GAD7_SCORE: server-derived from a completed
+  // `MentalHealthAssessment`, `source = COMPUTED`, one row per administration.
+  // Note the inverted direction versus PHQ-9 / GAD-7: HIGHER is better for both.
+  WHO5_SCORE // score (0–100) — WHO-5 well-being percentage (raw 0–25 × 4). Opt-in. See MentalHealthAssessment.
+  SCI_SCORE // score (0–32) — Sleep Condition Indicator total; higher = better sleep. Opt-in. See MentalHealthAssessment.
 
   @@map("measurement_type")
 }
 
 /// v1.25 — validated mental-health self-assessment instruments: PHQ-9
 /// (depression) + GAD-7 (anxiety). The discriminator on
-/// `MentalHealthAssessment`; extensible (WHO-5 / PSS-10 are natural future
-/// siblings) without a schema change.
+/// `MentalHealthAssessment`. v1.27.9 adds the WHO-5 well-being index and the
+/// Sleep Condition Indicator (SCI) — same administration contract, inverted
+/// score direction (higher = better).
 enum AssessmentInstrument {
   PHQ9
   GAD7
+  WHO5
+  SCI
 
   @@map("assessment_instrument")
 }
diff --git a/src/app/api/mental-health/assessments/__tests__/route.test.ts b/src/app/api/mental-health/assessments/__tests__/route.test.ts
index ec64359db..24f2ba941 100644
--- a/src/app/api/mental-health/assessments/__tests__/route.test.ts
+++ b/src/app/api/mental-health/assessments/__tests__/route.test.ts
@@ -284,6 +284,98 @@ describe("POST /api/mental-health/assessments", () => {
     expect(createArg.data.externalId).toBe("outbox-aa01");
   });
 
+  it("scores a WHO-5 check-in as raw-sum × 4 and projects a WHO5_SCORE measurement", async () => {
+    // Raw 3+3+2+2+2 = 12 → reported 48 (below the WHO "below 50" cut → low).
+    vi.mocked(prisma.mentalHealthAssessment.create).mockResolvedValue({
+      id: "mha_who5",
+      instrument: "WHO5",
+      locale: "en",
+      version: "standard",
+      totalScore: 48,
+      severityBand: "low",
+      item9Flagged: false,
+      crisisShownAt: null,
+      takenAt: new Date("2026-06-28T00:00:00.000Z"),
+      createdAt: new Date("2026-06-28T00:00:00.000Z"),
+    } as never);
+
+    const res = await callPost(
+      makeReq({ instrument: "WHO5", items: [3, 3, 2, 2, 2] }),
+    );
+    expect(res.status).toBe(201);
+
+    const createArg = vi.mocked(prisma.mentalHealthAssessment.create).mock
+      .calls[0][0] as {
+      data: { totalScore: number; severityBand: string; item9Flagged: boolean };
+    };
+    expect(createArg.data.totalScore).toBe(48);
+    expect(createArg.data.severityBand).toBe("low");
+    // Positively-worded instrument, no safety item — never flagged.
+    expect(createArg.data.item9Flagged).toBe(false);
+
+    const measArg = vi.mocked(prisma.measurement.create).mock.calls[0][0] as {
+      data: { type: string; value: number; source: string };
+    };
+    expect(measArg.data.type).toBe("WHO5_SCORE");
+    expect(measArg.data.value).toBe(48);
+    expect(measArg.data.source).toBe("COMPUTED");
+
+    const body = (await res.json()) as {
+      data: { crisis: unknown; actionThreshold: number };
+    };
+    // No crisis routing on the WHO-5 — the ≤50 pointer is client-side copy.
+    expect(body.data.crisis).toBeNull();
+    expect(body.data.actionThreshold).toBe(50);
+  });
+
+  it("accepts an SCI check-in (0–4 anchors) and projects an SCI_SCORE measurement", async () => {
+    vi.mocked(prisma.mentalHealthAssessment.create).mockResolvedValue({
+      id: "mha_sci",
+      instrument: "SCI",
+      locale: "en",
+      version: "standard",
+      totalScore: 16,
+      severityBand: "belowThreshold",
+      item9Flagged: false,
+      crisisShownAt: null,
+      takenAt: new Date("2026-06-28T00:00:00.000Z"),
+      createdAt: new Date("2026-06-28T00:00:00.000Z"),
+    } as never);
+
+    // Total 4+3+2+1+0+4+1+1 = 16 → the paper's ≤16 probable-insomnia range.
+    const res = await callPost(
+      makeReq({ instrument: "SCI", items: [4, 3, 2, 1, 0, 4, 1, 1] }),
+    );
+    expect(res.status).toBe(201);
+
+    const createArg = vi.mocked(prisma.mentalHealthAssessment.create).mock
+      .calls[0][0] as { data: { totalScore: number; severityBand: string } };
+    expect(createArg.data.totalScore).toBe(16);
+    expect(createArg.data.severityBand).toBe("belowThreshold");
+
+    const measArg = vi.mocked(prisma.measurement.create).mock.calls[0][0] as {
+      data: { type: string; value: number; source: string };
+    };
+    expect(measArg.data.type).toBe("SCI_SCORE");
+    expect(measArg.data.value).toBe(16);
+    expect(measArg.data.source).toBe("COMPUTED");
+  });
+
+  it("rejects an out-of-scale answer for the instrument with 422 (SCI max 4, PHQ-9 max 3)", async () => {
+    // 5 is a legal WHO-5 answer but out of scale for the SCI…
+    const sciRes = await callPost(
+      makeReq({ instrument: "SCI", items: [5, 3, 2, 1, 0, 4, 1, 1] }),
+    );
+    expect(sciRes.status).toBe(422);
+    // …and 4 is out of scale for the PHQ-9.
+    const phqRes = await callPost(
+      makeReq({ instrument: "PHQ9", items: [4, 0, 0, 0, 0, 0, 0, 0, 0] }),
+    );
+    expect(phqRes.status).toBe(422);
+    expect(prisma.mentalHealthAssessment.create).not.toHaveBeenCalled();
+    expect(prisma.measurement.create).not.toHaveBeenCalled();
+  });
+
   it("rejects a wrong item count with 422 and never writes", async () => {
     const res = await callPost(
       makeReq({ instrument: "PHQ9", items: [1, 2, 3] }), // 3 ≠ 9
diff --git a/src/app/api/mental-health/assessments/route.ts b/src/app/api/mental-health/assessments/route.ts
index 457d82dd1..939802cdb 100644
--- a/src/app/api/mental-health/assessments/route.ts
+++ b/src/app/api/mental-health/assessments/route.ts
@@ -229,8 +229,9 @@ async function postAssessment(request: NextRequest): Promise<Response> {
     if (existing) return respondExisting(existing);
   }
 
-  // Server-authoritative scoring (the client never computes these).
-  const total = scoreTotal(items);
+  // Server-authoritative scoring (the client never computes these). The
+  // total is the REPORTED score — the WHO-5 projects raw-sum × 4 (0–100).
+  const total = scoreTotal(id, items);
   const band = severityBand(id, total);
   const flagged = isSafetyFlagged(id, items);
   const presentedLocale = locale ?? user.locale ?? "en";
diff --git a/src/lib/__tests__/measurement-type-enum-coverage.test.ts b/src/lib/__tests__/measurement-type-enum-coverage.test.ts
index 6f98364cd..d4869a3cc 100644
--- a/src/lib/__tests__/measurement-type-enum-coverage.test.ts
+++ b/src/lib/__tests__/measurement-type-enum-coverage.test.ts
@@ -105,10 +105,14 @@ const EXPECTED_TYPES = [
   "PAIN_NRS",
   "WAIST_CIRCUMFERENCE",
   "WAIST_TO_HEIGHT",
+  // ── v1.27.9 — screening scores (WHO-5 percentage 0–100, SCI total 0–32;
+  // both server-derived from a completed assessment, higher = better) ──
+  "WHO5_SCORE",
+  "SCI_SCORE",
 ] as const;
 
 describe("measurementTypeEnum coverage", () => {
-  it("exposes the 73 canonical measurement types", () => {
+  it("exposes the 75 canonical measurement types", () => {
     expect([...measurementTypeEnum.options].sort()).toEqual(
       [...EXPECTED_TYPES].sort(),
     );
@@ -264,6 +268,12 @@ describe("measurementTypeEnum coverage", () => {
     "PAIN_NRS",
     "WAIST_CIRCUMFERENCE",
     "WAIST_TO_HEIGHT",
+    // v1.27.9 — WHO-5 / SCI screening totals follow the PHQ-9 / GAD-7
+    // precedent: opt-in questionnaire derivations, excluded from the vitals
+    // table; they ride the module-gated mental-health export section
+    // instead. See doctor-report-pdf-core.ts for the matching rationale.
+    "WHO5_SCORE",
+    "SCI_SCORE",
   ]);
 
   it("doctor-report PDF vital types cover the canonical enum minus documented exclusions", () => {
diff --git a/src/lib/jobs/__tests__/reminder-satisfy.test.ts b/src/lib/jobs/__tests__/reminder-satisfy.test.ts
index add9c1298..ea5d9f841 100644
--- a/src/lib/jobs/__tests__/reminder-satisfy.test.ts
+++ b/src/lib/jobs/__tests__/reminder-satisfy.test.ts
@@ -184,6 +184,28 @@ describe("runReminderSatisfyForUser", () => {
     expect(updates[0].data.lastSatisfiedAt).toEqual(measuredAt);
   });
 
+  it("satisfies the WHO-5 / SCI screening reminders on the identical contract (v1.27.9)", async () => {
+    for (const measurementType of ["WHO5_SCORE", "SCI_SCORE"]) {
+      const measuredAt = new Date("2026-07-01T10:00:00Z");
+      const { prisma, updates } = makePrisma({
+        reminders: [reminderRow({ measurementType, intervalDays: 28 })],
+        measurement: { measuredAt },
+      });
+      const isModuleEnabled = vi.fn(async () => true);
+
+      const summary = await runReminderSatisfyForUser(
+        prisma as never,
+        "u1",
+        new Date("2026-07-01T12:00:00Z"),
+        { isModuleEnabled },
+      );
+
+      expect(summary.satisfied, `${measurementType} should satisfy`).toBe(1);
+      expect(isModuleEnabled).toHaveBeenCalledWith("u1", "mentalHealth");
+      expect(updates[0].data.lastSatisfiedAt).toEqual(measuredAt);
+    }
+  });
+
   it("produces no engine activity for a screening reminder when the mental-health module is off", async () => {
     const { prisma, updates } = makePrisma({
       reminders: [
diff --git a/src/lib/jobs/measurement-reminder.ts b/src/lib/jobs/measurement-reminder.ts
index 1138cf54b..6041c8d05 100644
--- a/src/lib/jobs/measurement-reminder.ts
+++ b/src/lib/jobs/measurement-reminder.ts
@@ -67,6 +67,8 @@ function moduleForMeasurementType(
       return "sleep";
     case "PHQ9_SCORE":
     case "GAD7_SCORE":
+    case "WHO5_SCORE":
+    case "SCI_SCORE":
       return "mentalHealth";
     default:
       return null;
diff --git a/src/lib/measurements/__tests__/apple-health-mapping.test.ts b/src/lib/measurements/__tests__/apple-health-mapping.test.ts
index d109e739c..f57427ded 100644
--- a/src/lib/measurements/__tests__/apple-health-mapping.test.ts
+++ b/src/lib/measurements/__tests__/apple-health-mapping.test.ts
@@ -89,6 +89,10 @@ const MEASUREMENT_TYPES_WITHOUT_HK_COUNTERPART = new Set<MeasurementType>([
   "GRIP_STRENGTH",
   "PAIN_NRS",
   "WAIST_TO_HEIGHT",
+  // v1.27.9 — WHO-5 / SCI screening totals: same in-app questionnaire
+  // derivation as PHQ-9 / GAD-7. No HK mapping by design.
+  "WHO5_SCORE",
+  "SCI_SCORE",
 ]);
 
 describe("APPLE_HEALTH_TYPE_MAP", () => {
diff --git a/src/lib/mental-health/__tests__/instruments.test.ts b/src/lib/mental-health/__tests__/instruments.test.ts
index a97e92853..55cdf3d9d 100644
--- a/src/lib/mental-health/__tests__/instruments.test.ts
+++ b/src/lib/mental-health/__tests__/instruments.test.ts
@@ -2,9 +2,14 @@ import { describe, it, expect } from "vitest";
 
 import {
   INSTRUMENTS,
+  INSTRUMENT_MEASUREMENT_TYPE,
+  hasValidatedItems,
+  isSafetyFlagged,
+  needsFollowUp,
+  optionLabelKey,
   scoreTotal,
   severityBand,
-  isSafetyFlagged,
+  stemKey,
 } from "../instruments";
 
 /**
@@ -12,19 +17,40 @@ import {
  * GAD-7 totals, the validated severity-band edges (5 / 10 / 15 / 20 and
  * 5 / 10 / 15), the ≥10 action threshold, and the item-9 ANY-non-zero safety
  * flag. A future off-by-one on any band edge or the safety predicate must fail
- * here. Ground truth: Kroenke 2001 (PHQ-9) / Spitzer 2006 (GAD-7), mirrored in
- * `.planning/research/v125/clinical-instruments.md`.
+ * here. Ground truth: Kroenke 2001 (PHQ-9) / Spitzer 2006 (GAD-7).
+ *
+ * v1.27.9 — the WHO-5 / SCI pins join. Ground truth: the official WHO
+ * publication WHO/UCN/MSD/MHE/2024.1 ("raw score … zero to 25 … multiplied by
+ * four" → 0–100; "a percentage score below 50 … an indication for further
+ * assessment") and Espie et al., BMJ Open 2014;4:e004183 ("total score ranges
+ * from 0 to 32, with higher values indicative of better sleep"; "an SCI
+ * cut-off ≤16 … 'probable insomnia disorder'").
  */
 describe("mental-health instruments", () => {
   describe("scoreTotal", () => {
-    it("sums the item answers", () => {
-      expect(scoreTotal([0, 1, 2, 3, 0, 1, 2, 3, 1])).toBe(13);
-      expect(scoreTotal([0, 0, 0, 0, 0, 0, 0])).toBe(0);
+    it("sums the item answers for PHQ-9 / GAD-7 (multiplier 1)", () => {
+      expect(scoreTotal("PHQ9", [0, 1, 2, 3, 0, 1, 2, 3, 1])).toBe(13);
+      expect(scoreTotal("GAD7", [0, 0, 0, 0, 0, 0, 0])).toBe(0);
     });
 
     it("returns the max when every item is 3", () => {
-      expect(scoreTotal(Array(9).fill(3))).toBe(27); // PHQ-9 max
-      expect(scoreTotal(Array(7).fill(3))).toBe(21); // GAD-7 max
+      expect(scoreTotal("PHQ9", Array(9).fill(3))).toBe(27); // PHQ-9 max
+      expect(scoreTotal("GAD7", Array(7).fill(3))).toBe(21); // GAD-7 max
+    });
+
+    it("WHO-5 reports raw-sum × 4 (the official 0–100 percentage)", () => {
+      // WHO scoring page: raw 0–25, "multiplied by four" → 0–100.
+      expect(scoreTotal("WHO5", [0, 0, 0, 0, 0])).toBe(0);
+      expect(scoreTotal("WHO5", [5, 5, 5, 5, 5])).toBe(100);
+      expect(scoreTotal("WHO5", [3, 3, 3, 3, 3])).toBe(60);
+      // Raw 12 (below the raw-13 cut) → 48 on the percentage scale.
+      expect(scoreTotal("WHO5", [3, 3, 2, 2, 2])).toBe(48);
+    });
+
+    it("SCI sums to 0–32 (higher = better sleep)", () => {
+      expect(scoreTotal("SCI", Array(8).fill(0))).toBe(0);
+      expect(scoreTotal("SCI", Array(8).fill(4))).toBe(32);
+      expect(scoreTotal("SCI", [4, 3, 2, 1, 0, 4, 1, 1])).toBe(16);
     });
   });
 
@@ -62,12 +88,47 @@ describe("mental-health instruments", () => {
     });
   });
 
-  describe("action threshold is ≥10 for both instruments", () => {
-    it("PHQ-9", () => {
-      expect(INSTRUMENTS.PHQ9.actionThreshold).toBe(10);
+  describe("severityBand — WHO-5 (below 50 = low; achievable totals are ×4)", () => {
+    const cases: Array<[number, string]> = [
+      [0, "low"],
+      [48, "low"], // raw 12 — below the WHO raw-13 cut
+      [52, "good"], // raw 13 — at/above the cut
+      [100, "good"],
+    ];
+    it.each(cases)("WHO5 total %i → %s", (total, band) => {
+      expect(severityBand("WHO5", total)).toBe(band);
     });
-    it("GAD-7", () => {
-      expect(INSTRUMENTS.GAD7.actionThreshold).toBe(10);
+  });
+
+  describe("severityBand — SCI (≤16 probable-insomnia range per Espie 2014)", () => {
+    const cases: Array<[number, string]> = [
+      [0, "belowThreshold"],
+      [16, "belowThreshold"],
+      [17, "aboveThreshold"],
+      [32, "aboveThreshold"],
+    ];
+    it.each(cases)("SCI total %i → %s", (total, band) => {
+      expect(severityBand("SCI", total)).toBe(band);
+    });
+  });
+
+  describe("needsFollowUp — direction-aware thresholds", () => {
+    it("PHQ-9 / GAD-7 point up (≥ 10)", () => {
+      expect(needsFollowUp("PHQ9", 9)).toBe(false);
+      expect(needsFollowUp("PHQ9", 10)).toBe(true);
+      expect(needsFollowUp("GAD7", 9)).toBe(false);
+      expect(needsFollowUp("GAD7", 10)).toBe(true);
+    });
+
+    it("WHO-5 points down (≤ 50 → gentle PHQ-9 pointer)", () => {
+      expect(needsFollowUp("WHO5", 48)).toBe(true);
+      expect(needsFollowUp("WHO5", 50)).toBe(true);
+      expect(needsFollowUp("WHO5", 52)).toBe(false);
+    });
+
+    it("SCI points down (≤ 16)", () => {
+      expect(needsFollowUp("SCI", 16)).toBe(true);
+      expect(needsFollowUp("SCI", 17)).toBe(false);
     });
   });
 
@@ -82,13 +143,70 @@ describe("mental-health instruments", () => {
     it("does not flag when item 9 = 0 even with a high total", () => {
       // Every other item maxed (24), item 9 = 0 → severe band, no flag.
       const items = [3, 3, 3, 3, 3, 3, 3, 3, 0];
-      expect(severityBand("PHQ9", scoreTotal(items))).toBe("severe");
+      expect(severityBand("PHQ9", scoreTotal("PHQ9", items))).toBe("severe");
       expect(isSafetyFlagged("PHQ9", items)).toBe(false);
     });
 
-    it("never flags GAD-7 (no safety item)", () => {
+    it("never flags the instruments without a safety item", () => {
       expect(isSafetyFlagged("GAD7", [3, 3, 3, 3, 3, 3, 3])).toBe(false);
+      expect(isSafetyFlagged("WHO5", [0, 0, 0, 0, 0])).toBe(false);
+      expect(isSafetyFlagged("SCI", [0, 0, 0, 0, 0, 0, 0, 0])).toBe(false);
       expect(INSTRUMENTS.GAD7.safetyItemIndex).toBeNull();
+      expect(INSTRUMENTS.WHO5.safetyItemIndex).toBeNull();
+      expect(INSTRUMENTS.SCI.safetyItemIndex).toBeNull();
+    });
+  });
+
+  describe("registry shape — the config the surfaces drive from", () => {
+    it("presents options in the source order (WHO-5 leads with 5, SCI with 4)", () => {
+      expect(INSTRUMENTS.WHO5.optionOrder).toEqual([5, 4, 3, 2, 1, 0]);
+      expect(INSTRUMENTS.SCI.optionOrder).toEqual([4, 3, 2, 1, 0]);
+      expect(INSTRUMENTS.PHQ9.optionOrder).toEqual([0, 1, 2, 3]);
+    });
+
+    it("resolves option-label keys per scheme (shared vs SCI per-item groups)", () => {
+      expect(optionLabelKey("PHQ9", 0, 2)).toBe("options.2");
+      expect(optionLabelKey("WHO5", 4, 5)).toBe("who5Options.5");
+      // SCI: items 1–2 duration, 3 nights, 4 quality, 5–7 impact, 8 problem duration.
+      expect(optionLabelKey("SCI", 0, 4)).toBe("sciOptions.duration.4");
+      expect(optionLabelKey("SCI", 2, 0)).toBe("sciOptions.nights.0");
+      expect(optionLabelKey("SCI", 3, 2)).toBe("sciOptions.quality.2");
+      expect(optionLabelKey("SCI", 6, 1)).toBe("sciOptions.impact.1");
+      expect(optionLabelKey("SCI", 7, 3)).toBe("sciOptions.problemDuration.3");
+    });
+
+    it("maps recall stems (WHO-5 one stem; SCI three sections; PHQ/GAD none)", () => {
+      expect(stemKey("WHO5", 0)).toBe("who5.period");
+      expect(stemKey("SCI", 0)).toBe("sci.night");
+      expect(stemKey("SCI", 3)).toBe("sci.night");
+      expect(stemKey("SCI", 4)).toBe("sci.impact");
+      expect(stemKey("SCI", 7)).toBe("sci.finally");
+      expect(stemKey("PHQ9", 0)).toBeNull();
+      expect(stemKey("GAD7", 0)).toBeNull();
+    });
+
+    it("declares validated item locales honestly (SCI = English only)", () => {
+      for (const locale of ["de", "en", "es", "fr", "it", "pl"]) {
+        expect(hasValidatedItems("WHO5", locale)).toBe(true);
+        expect(hasValidatedItems("PHQ9", locale)).toBe(true);
+      }
+      expect(hasValidatedItems("SCI", "en")).toBe(true);
+      expect(hasValidatedItems("SCI", "en-GB")).toBe(true);
+      expect(hasValidatedItems("SCI", "de")).toBe(false);
+      expect(hasValidatedItems("SCI", "pl")).toBe(false);
+    });
+
+    it("projects each instrument onto its measurement type", () => {
+      expect(INSTRUMENT_MEASUREMENT_TYPE.WHO5).toBe("WHO5_SCORE");
+      expect(INSTRUMENT_MEASUREMENT_TYPE.SCI).toBe("SCI_SCORE");
+    });
+
+    it("every instrument carries a non-empty attribution line", () => {
+      for (const def of Object.values(INSTRUMENTS)) {
+        expect(def.attribution.length).toBeGreaterThan(20);
+      }
+      expect(INSTRUMENTS.WHO5.attribution).toContain("CC BY-NC-SA 3.0 IGO");
+      expect(INSTRUMENTS.SCI.attribution).toContain("BMJ Open");
     });
   });
 });
diff --git a/src/lib/mental-health/instruments.ts b/src/lib/mental-health/instruments.ts
index d54b7ac44..92103184b 100644
--- a/src/lib/mental-health/instruments.ts
+++ b/src/lib/mental-health/instruments.ts
@@ -1,58 +1,123 @@
 /**
  * v1.25 — validated mental-health screener definitions (PHQ-9 + GAD-7).
+ * v1.27.9 — the registry generalises to carry the WHO-5 well-being index and
+ * the Sleep Condition Indicator (SCI) on the same infrastructure: per-item
+ * answer scales, response-option schemes, score direction, and the reported
+ * total (WHO-5 reports raw-sum × 4 as a 0–100 percentage) are now instrument
+ * properties instead of PHQ/GAD assumptions.
  *
- * Pure, server-authoritative scoring. The instrument item wording, 0–3 scale,
- * totals, and severity bands are taken from the primary sources (Kroenke 2001
- * for PHQ-9; Spitzer 2006 for GAD-7). This module owns the canonical NUMERIC
- * contract; the human wording lives in `messages/*.json` under
- * `mentalHealth.items.*` (officially-validated translations per locale, English
- * fallback otherwise — re-wording invalidates the score). The de/es/fr/it/pl
- * item wordings are the public-domain Pfizer/PRIME-MD validated localized
- * versions distributed via the MAPI Research Trust (de: Löwe/Gräfe et al.); they
- * are NOT machine-translated. See `.planning/research/v125/clinical-instruments.md`.
+ * Pure, server-authoritative scoring. Item wording, response anchors, scoring
+ * and band thresholds are taken from the primary sources only:
+ *   - PHQ-9: Kroenke 2001; GAD-7: Spitzer 2006 (public-domain Pfizer grant).
+ *   - WHO-5: WHO/UCN/MSD/MHE/2024.1 (© WHO 2024, CC BY-NC-SA 3.0 IGO) — raw
+ *     0–25, × 4 → 0–100; "a percentage score below 50 … an indication for
+ *     further assessment". WHO publishes official translations for all six
+ *     app locales; they ship verbatim.
+ *   - SCI: Espie et al., BMJ Open 2014;4:e004183 (© Sleepio Ltd, licensed
+ *     free for non-commercial use, CC BY-NC) — 8 items, 0–4 each, total 0–32,
+ *     HIGHER = better sleep; "a score of ≤16 … seems reasonable to detect
+ *     possible insomnia disorder". Item text is validated in English; app
+ *     locales without a validated translation present the English items.
+ * This module owns the canonical NUMERIC contract; the human wording lives in
+ * `messages/*.json` under `mentalHealth.items.*` (validated translations per
+ * locale where they exist — re-wording invalidates the score). See
+ * `.planning/research/screening-instruments-2026-07.md`.
  *
  * PHQ-9 item 9 (index 8) is the passive self-harm ideation screen and is the
  * safety-critical field (see `crisis-resources.ts` + the API handler): any
- * non-zero answer triggers a calm, non-alarmist crisis-resource signpost. The
- * raw item answers are NEVER exposed to the Coach / Insights / export surfaces —
- * only the derived total score rides a `*_SCORE` Measurement row.
+ * non-zero answer triggers a calm, non-alarmist crisis-resource signpost.
+ * Neither the WHO-5 (all items positively worded) nor the SCI (sleep-specific
+ * items only) carries a crisis item. The raw item answers are NEVER exposed
+ * to the Coach / Insights / export surfaces — only the derived total score
+ * rides a `*_SCORE` Measurement row.
  */
 
-export type InstrumentId = "PHQ9" | "GAD7";
+export type InstrumentId = "PHQ9" | "GAD7" | "WHO5" | "SCI";
+
+export interface InstrumentDefinition {
+  id: InstrumentId;
+  /** Lowercase i18n slug — the key segment under `mentalHealth.*`. */
+  i18nKey: "phq9" | "gad7" | "who5" | "sci";
+  /** Number of scored items (PHQ-9 = 9, GAD-7 = 7, WHO-5 = 5, SCI = 8). */
+  itemCount: number;
+  /** Highest per-item answer value (PHQ/GAD 3, SCI 4, WHO-5 5). */
+  itemMax: number;
+  /**
+   * Answer values in the order the source instrument presents them. The
+   * PHQ/GAD forms run 0→3; the WHO-5 form leads with 5 ("All of the time");
+   * the SCI form leads with 4.
+   */
+  optionOrder: readonly number[];
+  /**
+   * i18n namespace for the response-option labels under `mentalHealth.`:
+   * without `optionGroups` one shared anchor set (`<ns>.<value>`); with
+   * `optionGroups` (SCI) per-item anchor groups (`<ns>.<group>.<value>`,
+   * group = `optionGroups[itemIndex]`).
+   */
+  optionNamespace: string;
+  optionGroups?: readonly string[];
+  /**
+   * Recall-stem caption key per item under `mentalHealth.stems.` — the WHO-5
+   * and SCI items are fragments under a shared stem on the source forms, so
+   * the wizard paints the applicable stem above the question. PHQ/GAD keep
+   * their frame in the instrument description line (shipped contract).
+   */
+  stemKeys?: readonly string[];
+  /** Multiplier from item-sum to the reported total (WHO-5: × 4). */
+  scoreMultiplier: number;
+  /** Inclusive REPORTED total range (WHO-5: 0–100 percentage). */
+  minScore: number;
+  maxScore: number;
+  /** Whether a HIGHER total is the good direction (WHO-5 / SCI). */
+  higherIsBetter: boolean;
+  /** Total-score LOINC for the FHIR/export contract; null when none exists. */
+  totalLoinc: string | null;
+  /** Severity bands, ordered low→high. `min`/`max` inclusive over the total. */
+  bands: ReadonlyArray<{ key: string; min: number; max: number }>;
+  /**
+   * Follow-up threshold on the reported scale. The concerning side follows
+   * the direction: PHQ/GAD ≥ threshold, WHO-5/SCI ≤ threshold (WHO-5 "below
+   * 50" — 50 itself is unreachable on the ×4 scale; SCI ≤ 16 per Espie 2014).
+   */
+  actionThreshold: number;
+  /** Item index (0-based) of the safety-critical self-harm item, or null. */
+  safetyItemIndex: number | null;
+  /**
+   * Locales whose bundled item wording is a validated translation. A locale
+   * outside this list renders the validated source-language items plus an
+   * honest chrome note — NEVER a self-made translation.
+   */
+  validatedItemLocales: readonly string[];
+  /**
+   * Required attribution — render VERBATIM on the instrument's start card and
+   * the result view (and in exports). Stays in English by convention (the
+   * developers' names and licence identifiers are not translated).
+   */
+  attribution: string;
+}
+
+const ALL_APP_LOCALES = ["de", "en", "es", "fr", "it", "pl"] as const;
 
 /**
- * Required attribution — render VERBATIM on every screen displaying the
- * instrument and in the PDF/FHIR export. The PHQ family is public-domain (Pfizer
- * 2010); this is the canonical footer text. By convention it stays in English
- * (the developers' names are not translated).
+ * The PHQ family is public-domain (Pfizer 2010); this is the canonical footer
+ * text per the instrument's own permission grant.
  */
-export const PHQ_GAD_ATTRIBUTION =
+const PHQ_GAD_ATTRIBUTION =
   "Developed by Drs. Robert L. Spitzer, Janet B.W. Williams, Kurt Kroenke and " +
   "colleagues, with an educational grant from Pfizer Inc. No permission " +
   "required to reproduce, translate, display or distribute.";
 
-export interface InstrumentDefinition {
-  id: InstrumentId;
-  /** Number of scored items (PHQ-9 = 9, GAD-7 = 7). */
-  itemCount: number;
-  /** Inclusive total range. */
-  minScore: number;
-  maxScore: number;
-  /** Total-score LOINC for the FHIR/export contract. */
-  totalLoinc: string;
-  /** Severity bands, ordered low→high. `min`/`max` inclusive over the total. */
-  bands: ReadonlyArray<{ key: string; min: number; max: number }>;
-  /** Optimal screening cut-off (≥ this total = consider professional follow-up). */
-  actionThreshold: number;
-  /** Item index (0-based) of the safety-critical self-harm item, or null. */
-  safetyItemIndex: number | null;
-}
-
 const PHQ9: InstrumentDefinition = {
   id: "PHQ9",
+  i18nKey: "phq9",
   itemCount: 9,
+  itemMax: 3,
+  optionOrder: [0, 1, 2, 3],
+  optionNamespace: "options",
+  scoreMultiplier: 1,
   minScore: 0,
   maxScore: 27,
+  higherIsBetter: false,
   totalLoinc: "44261-6",
   bands: [
     { key: "minimal", min: 0, max: 4 },
@@ -64,13 +129,21 @@ const PHQ9: InstrumentDefinition = {
   actionThreshold: 10,
   // Item 9 ("Thoughts that you would be better off dead…") — the safety field.
   safetyItemIndex: 8,
+  validatedItemLocales: ALL_APP_LOCALES,
+  attribution: PHQ_GAD_ATTRIBUTION,
 };
 
 const GAD7: InstrumentDefinition = {
   id: "GAD7",
+  i18nKey: "gad7",
   itemCount: 7,
+  itemMax: 3,
+  optionOrder: [0, 1, 2, 3],
+  optionNamespace: "options",
+  scoreMultiplier: 1,
   minScore: 0,
   maxScore: 21,
+  higherIsBetter: false,
   totalLoinc: "70274-6",
   bands: [
     { key: "minimal", min: 0, max: 4 },
@@ -80,25 +153,137 @@ const GAD7: InstrumentDefinition = {
   ],
   actionThreshold: 10,
   safetyItemIndex: null,
+  validatedItemLocales: ALL_APP_LOCALES,
+  attribution: PHQ_GAD_ATTRIBUTION,
+};
+
+/**
+ * WHO-5 well-being index — five positively-worded items over the last two
+ * weeks, 6-point 5→0 scale. Reported score = raw sum × 4 (0–100, higher =
+ * better well-being) per the official WHO scoring. "A percentage score below
+ * 50 … has been suggested as a cut-off for poor mental well-being and as an
+ * indication for further assessment" (WHO/UCN/MSD/MHE/2024.1) — the result
+ * view answers a ≤ 50 total with a gentle pointer to the PHQ-9 check-in.
+ * Achievable totals are multiples of 4, so the 0–50 band equals "below 50".
+ */
+const WHO5: InstrumentDefinition = {
+  id: "WHO5",
+  i18nKey: "who5",
+  itemCount: 5,
+  itemMax: 5,
+  optionOrder: [5, 4, 3, 2, 1, 0],
+  optionNamespace: "who5Options",
+  stemKeys: Array(5).fill("who5.period"),
+  scoreMultiplier: 4,
+  minScore: 0,
+  maxScore: 100,
+  higherIsBetter: true,
+  totalLoinc: null,
+  bands: [
+    { key: "low", min: 0, max: 50 },
+    { key: "good", min: 51, max: 100 },
+  ],
+  actionThreshold: 50,
+  safetyItemIndex: null,
+  // WHO publishes official de/en/es/fr/it/pl versions — all bundled verbatim.
+  validatedItemLocales: ALL_APP_LOCALES,
+  attribution:
+    "World Health Organization. The World Health Organization-Five Well-Being " +
+    "Index (WHO-5). Geneva: World Health Organization; 2024. Licence: " +
+    "CC BY-NC-SA 3.0 IGO. WHO does not endorse this application.",
+};
+
+/**
+ * Sleep Condition Indicator — eight DSM-5-aligned items, 0–4 each with
+ * item-specific anchors, total 0–32, HIGHER = better sleep. "A score of ≤16
+ * on the SCI seems reasonable to detect possible insomnia disorder" (Espie
+ * et al. 2014) — the band wording stays neutral per the paper, no diagnosis
+ * language. Items 1–4 ask about a typical night in the last month, items 5–7
+ * about the past month's daytime impact, item 8 about problem duration.
+ */
+const SCI: InstrumentDefinition = {
+  id: "SCI",
+  i18nKey: "sci",
+  itemCount: 8,
+  itemMax: 4,
+  optionOrder: [4, 3, 2, 1, 0],
+  optionNamespace: "sciOptions",
+  optionGroups: [
+    "duration",
+    "duration",
+    "nights",
+    "quality",
+    "impact",
+    "impact",
+    "impact",
+    "problemDuration",
+  ],
+  stemKeys: [
+    "sci.night",
+    "sci.night",
+    "sci.night",
+    "sci.night",
+    "sci.impact",
+    "sci.impact",
+    "sci.impact",
+    "sci.finally",
+  ],
+  scoreMultiplier: 1,
+  minScore: 0,
+  maxScore: 32,
+  higherIsBetter: true,
+  totalLoinc: null,
+  bands: [
+    { key: "belowThreshold", min: 0, max: 16 },
+    { key: "aboveThreshold", min: 17, max: 32 },
+  ],
+  actionThreshold: 16,
+  safetyItemIndex: null,
+  // Validated in English (the CC BY-NC BMJ Open publication). French/Italian
+  // validations exist in the literature but their item text is not openly
+  // redistributable, so every non-EN locale presents the English items with
+  // an honest note — never a self-made translation.
+  validatedItemLocales: ["en"],
+  attribution:
+    "Espie CA, Kyle SD, Hames P, et al. The Sleep Condition Indicator: a " +
+    "clinical screening tool to evaluate insomnia disorder. BMJ Open " +
+    "2014;4:e004183. © Sleepio Limited; free for non-commercial use (CC BY-NC).",
 };
 
 export const INSTRUMENTS: Record<InstrumentId, InstrumentDefinition> = {
   PHQ9,
   GAD7,
+  WHO5,
+  SCI,
 };
 
+/** Landing / history ordering — the shipped pair first, then the new pair. */
+export const INSTRUMENT_ORDER: readonly InstrumentId[] = [
+  "PHQ9",
+  "GAD7",
+  "WHO5",
+  "SCI",
+];
+
 /** The DB MeasurementType the instrument's total score projects to. */
 export const INSTRUMENT_MEASUREMENT_TYPE: Record<InstrumentId, string> = {
   PHQ9: "PHQ9_SCORE",
   GAD7: "GAD7_SCORE",
+  WHO5: "WHO5_SCORE",
+  SCI: "SCI_SCORE",
 };
 
-/** Sum the item answers into a total (server-authoritative). */
-export function scoreTotal(items: readonly number[]): number {
-  return items.reduce((sum, v) => sum + v, 0);
+/**
+ * The REPORTED total for a completed administration (server-authoritative):
+ * item-sum × the instrument's multiplier (WHO-5 reports the 0–100 percentage,
+ * everything else the raw sum).
+ */
+export function scoreTotal(id: InstrumentId, items: readonly number[]): number {
+  const sum = items.reduce((acc, v) => acc + v, 0);
+  return sum * INSTRUMENTS[id].scoreMultiplier;
 }
 
-/** Resolve the severity-band key for a total score. */
+/** Resolve the severity-band key for a reported total score. */
 export function severityBand(id: InstrumentId, total: number): string {
   const def = INSTRUMENTS[id];
   const band = def.bands.find((b) => total >= b.min && total <= b.max);
@@ -106,6 +291,50 @@ export function severityBand(id: InstrumentId, total: number): string {
   return band?.key ?? def.bands[def.bands.length - 1].key;
 }
 
+/**
+ * Whether the gentle follow-up hint applies for a reported total. Direction-
+ * aware: PHQ-9/GAD-7 point up (≥ 10), WHO-5 and the SCI point down (≤ 50 /
+ * ≤ 16 — lower totals mean lower well-being / worse sleep).
+ */
+export function needsFollowUp(id: InstrumentId, total: number): boolean {
+  const def = INSTRUMENTS[id];
+  return def.higherIsBetter
+    ? total <= def.actionThreshold
+    : total >= def.actionThreshold;
+}
+
+/**
+ * i18n key (under `mentalHealth.`) for one response option of one item —
+ * shared anchors (`options.2`), instrument-specific shared anchors
+ * (`who5Options.5`), or the SCI's per-item anchor groups
+ * (`sciOptions.duration.4`).
+ */
+export function optionLabelKey(
+  id: InstrumentId,
+  itemIndex: number,
+  value: number,
+): string {
+  const def = INSTRUMENTS[id];
+  return def.optionGroups
+    ? `${def.optionNamespace}.${def.optionGroups[itemIndex]}.${value}`
+    : `${def.optionNamespace}.${value}`;
+}
+
+/** Stem caption key (under `mentalHealth.stems.`) for an item, or null. */
+export function stemKey(id: InstrumentId, itemIndex: number): string | null {
+  return INSTRUMENTS[id].stemKeys?.[itemIndex] ?? null;
+}
+
+/**
+ * Whether the bundled item wording for `locale` is a validated translation.
+ * When false the surface shows the validated source-language items plus a
+ * localized "validated in English" chrome note.
+ */
+export function hasValidatedItems(id: InstrumentId, locale: string): boolean {
+  const base = locale.toLowerCase().split("-")[0];
+  return INSTRUMENTS[id].validatedItemLocales.includes(base);
+}
+
 /**
  * Whether the safety signpost must be shown for these answers. True iff the
  * instrument has a safety item and that item was answered with any non-zero
diff --git a/src/lib/openapi/routes/mental-health.ts b/src/lib/openapi/routes/mental-health.ts
index 21f66a1fd..5f61be24d 100644
--- a/src/lib/openapi/routes/mental-health.ts
+++ b/src/lib/openapi/routes/mental-health.ts
@@ -1,6 +1,6 @@
 /**
  * OpenAPI route table for the opt-in mental-health screeners
- * (`/api/mental-health/assessments`). PHQ-9 / GAD-7.
+ * (`/api/mental-health/assessments`). PHQ-9 / GAD-7 / WHO-5 / SCI.
  *
  * Part of the OpenAPI route table; aggregated in `./index.ts`. The request body
  * reuses the runtime Zod schema from `@/lib/validations/mental-health` so the
@@ -23,7 +23,7 @@ import { dataEnvelope, stdResponses } from "./shared";
 createAssessmentSchema.meta({
   id: "CreateMentalHealthAssessmentRequest",
   description:
-    "Record one completed PHQ-9 (9 items) / GAD-7 (7 items) administration. Each item answer is 0–3; the array length must match the instrument. The item answers are encrypted at rest and never returned. The server computes the total + severity band + item-9 safety flag. Opt-in, beside mood tracking — this is a screening surface, not a diagnosis.",
+    "Record one completed screener administration: PHQ-9 (9 items, 0–3), GAD-7 (7 items, 0–3), WHO-5 (5 items, 0–5) or SCI (8 items, 0–4). The array length and per-item ceiling must match the instrument. The item answers are encrypted at rest and never returned. The server computes the total (WHO-5 reports raw-sum × 4 as 0–100) + severity band + item-9 safety flag. Opt-in, beside mood tracking — this is a screening surface, not a diagnosis.",
 });
 
 listAssessmentsSchema.meta({
@@ -35,7 +35,7 @@ listAssessmentsSchema.meta({
 const assessmentRow = z
   .object({
     id: z.string(),
-    instrument: z.enum(["PHQ9", "GAD7"]),
+    instrument: z.enum(["PHQ9", "GAD7", "WHO5", "SCI"]),
     locale: z.string(),
     version: z.string(),
     totalScore: z.number(),
@@ -87,7 +87,7 @@ export const mentalHealthPaths: NonNullable<ZodOpenApiObject["paths"]> = {
       tags: ["Mental health"],
       summary: "List the caller's screener history",
       description:
-        "Returns PHQ-9 / GAD-7 administrations (newest first). Totals + bands + flags only; raw item answers are never returned.",
+        "Returns PHQ-9 / GAD-7 / WHO-5 / SCI administrations (newest first). Totals + bands + flags only; raw item answers are never returned.",
       requestParams: { query: listAssessmentsSchema },
       responses: {
         "200": {
@@ -106,9 +106,9 @@ export const mentalHealthPaths: NonNullable<ZodOpenApiObject["paths"]> = {
     },
     post: {
       tags: ["Mental health"],
-      summary: "Record a completed PHQ-9 / GAD-7 screener",
+      summary: "Record a completed screener",
       description:
-        "Stores one administration (item answers encrypted) and writes the derived total as a server-owned PHQ9_SCORE / GAD7_SCORE measurement (source COMPUTED — never client-writable). On a positive PHQ-9 item-9 the response carries the locale-aware crisis-resource set.",
+        "Stores one administration (item answers encrypted) and writes the derived total as a server-owned PHQ9_SCORE / GAD7_SCORE / WHO5_SCORE / SCI_SCORE measurement (source COMPUTED — never client-writable). WHO-5 and SCI totals run HIGHER = better; their follow-up thresholds point downwards (≤ 50 / ≤ 16). On a positive PHQ-9 item-9 the response carries the locale-aware crisis-resource set.",
       requestBody: {
         content: {
           "application/json": { schema: createAssessmentSchema },
diff --git a/src/lib/validations/__tests__/measurement-reminders.test.ts b/src/lib/validations/__tests__/measurement-reminders.test.ts
index 9ac7458cc..325e21019 100644
--- a/src/lib/validations/__tests__/measurement-reminders.test.ts
+++ b/src/lib/validations/__tests__/measurement-reminders.test.ts
@@ -37,10 +37,26 @@ describe("measurementReminderTypeEnum (V3 — completeness)", () => {
         // v1.27.6 — plannable mental-wellbeing screenings
         "PHQ9_SCORE",
         "GAD7_SCORE",
+        // v1.27.9 — WHO-5 + SCI join on the identical contract
+        "WHO5_SCORE",
+        "SCI_SCORE",
       ]),
     );
   });
 
+  it("accepts the WHO-5 / SCI screenings with the 4-week default cadence", () => {
+    for (const measurementType of ["WHO5_SCORE", "SCI_SCORE"]) {
+      const parsed = createMeasurementReminderSchema.safeParse({
+        label: "Screening check-in",
+        measurementType,
+        intervalDays: 28,
+      });
+      expect(parsed.success, `expected ${measurementType} to be allowed`).toBe(
+        true,
+      );
+    }
+  });
+
   it("accepts a plannable screening reminder with the 4-week default cadence", () => {
     const parsed = createMeasurementReminderSchema.safeParse({
       label: "PHQ-9 Check-in",
diff --git a/src/lib/validations/__tests__/measurement.test.ts b/src/lib/validations/__tests__/measurement.test.ts
index b110d1e9f..281e7cdf9 100644
--- a/src/lib/validations/__tests__/measurement.test.ts
+++ b/src/lib/validations/__tests__/measurement.test.ts
@@ -473,9 +473,15 @@ describe("measurement validation", () => {
     it("rejects a COMPUTED-attributed screener score row on a client write", () => {
       // v1.27.6 — the mental-wellbeing screener projects each completed
       // administration onto a COMPUTED-source PHQ9_SCORE / GAD7_SCORE row
-      // (the RECOVERY_SCORE precedent). COMPUTED is not client-attributable,
-      // so a client can never mint a server-owned score trend point.
-      for (const type of ["PHQ9_SCORE", "GAD7_SCORE"]) {
+      // (the RECOVERY_SCORE precedent; v1.27.9 adds WHO5_SCORE / SCI_SCORE).
+      // COMPUTED is not client-attributable, so a client can never mint a
+      // server-owned score trend point.
+      for (const type of [
+        "PHQ9_SCORE",
+        "GAD7_SCORE",
+        "WHO5_SCORE",
+        "SCI_SCORE",
+      ]) {
         const parsed = createMeasurementSchema.safeParse({
           type,
           value: 5,
diff --git a/src/lib/validations/measurement-reminders.ts b/src/lib/validations/measurement-reminders.ts
index 39794123a..0ee684b90 100644
--- a/src/lib/validations/measurement-reminders.ts
+++ b/src/lib/validations/measurement-reminders.ts
@@ -64,11 +64,16 @@ export const measurementReminderTypeEnum = z
     // the dispatcher (see `moduleForMeasurementType`).
     "PHQ9_SCORE",
     "GAD7_SCORE",
+    // v1.27.9 — WHO-5 + SCI join the plannable screenings on the identical
+    // contract (auto-resolve on the server-owned COMPUTED score row, module-
+    // gated in the dispatcher).
+    "WHO5_SCORE",
+    "SCI_SCORE",
   ])
   .meta({
     id: "MeasurementReminderType",
     description:
-      "Auto-resolve target metric (vitals + body-composition family + the PHQ-9 / GAD-7 screenings). BP resolves on BLOOD_PRESSURE_SYS (the SYS row is the 'a BP was measured' sentinel); a screening reminder resolves on the server-written PHQ9_SCORE / GAD7_SCORE row when a check-in completes. Omit for a free-text Vorsorge that resolves only on a manual satisfy or a matching lab result.",
+      "Auto-resolve target metric (vitals + body-composition family + the PHQ-9 / GAD-7 / WHO-5 / SCI screenings). BP resolves on BLOOD_PRESSURE_SYS (the SYS row is the 'a BP was measured' sentinel); a screening reminder resolves on the server-written *_SCORE row when a check-in completes. Omit for a free-text Vorsorge that resolves only on a manual satisfy or a matching lab result.",
   });
 
 export type MeasurementReminderType = z.infer<
@@ -85,6 +90,8 @@ export type MeasurementReminderType = z.infer<
 export const SCREENING_REMINDER_TYPES: ReadonlySet<string> = new Set([
   "PHQ9_SCORE",
   "GAD7_SCORE",
+  "WHO5_SCORE",
+  "SCI_SCORE",
 ]);
 
 /** Whether a reminder's `measurementType` targets a screening check-in. */
diff --git a/src/lib/validations/measurement.ts b/src/lib/validations/measurement.ts
index e78adc2be..5b5961e8d 100644
--- a/src/lib/validations/measurement.ts
+++ b/src/lib/validations/measurement.ts
@@ -135,6 +135,11 @@ export const measurementTypeEnum = z.enum([
   "PAIN_NRS",
   "WAIST_CIRCUMFERENCE",
   "WAIST_TO_HEIGHT",
+  // ── v1.27.9 — screening scores (same assessment contract as PHQ-9/GAD-7,
+  // inverted direction: HIGHER is better). WHO-5 stores the reported 0–100
+  // percentage (raw sum × 4); SCI stores the 0–32 total.
+  "WHO5_SCORE",
+  "SCI_SCORE",
 ]);
 
 /**
@@ -379,6 +384,9 @@ const unitMap: Record<string, string> = {
   // ── v1.25 — clinical-signals wave ──
   PHQ9_SCORE: "score",
   GAD7_SCORE: "score",
+  // ── v1.27.9 — screening scores ──
+  WHO5_SCORE: "score",
+  SCI_SCORE: "score",
   GRIP_STRENGTH: "kg",
   PAIN_NRS: "score",
   WAIST_CIRCUMFERENCE: "cm",
@@ -581,6 +589,10 @@ export const VALUE_RANGES: Record<string, { min: number; max: number }> = {
   // PHQ-9 total 0–27, GAD-7 total 0–21 — server-derived from the screener.
   PHQ9_SCORE: { min: 0, max: 27 },
   GAD7_SCORE: { min: 0, max: 21 },
+  // ── v1.27.9 — screening scores. WHO-5 reported percentage 0–100 (raw × 4),
+  // SCI total 0–32 — both server-derived, higher = better.
+  WHO5_SCORE: { min: 0, max: 100 },
+  SCI_SCORE: { min: 0, max: 32 },
   // Grip strength kg — a child can read in the single digits, an elite athlete
   // tops ~90 kg; 120 is a generous ceiling that still rejects sensor noise.
   GRIP_STRENGTH: { min: 0, max: 120 },
diff --git a/src/lib/validations/mental-health.ts b/src/lib/validations/mental-health.ts
index 9cd08f999..8415afe60 100644
--- a/src/lib/validations/mental-health.ts
+++ b/src/lib/validations/mental-health.ts
@@ -1,8 +1,10 @@
 /**
  * v1.25 — request/response validation for the opt-in mental-health screeners
- * (PHQ-9 / GAD-7). The item answers are 0–3 integers; the array length must
- * match the instrument (PHQ-9 = 9, GAD-7 = 7). `userId` is NEVER a body field —
- * it is narrowed from the session in the handler (CLAUDE.md convention).
+ * (PHQ-9 / GAD-7; v1.27.9 adds WHO-5 + SCI). The item answers are small
+ * integers whose ceiling is instrument-specific (PHQ/GAD 0–3, SCI 0–4,
+ * WHO-5 0–5); the array length must match the instrument. `userId` is NEVER
+ * a body field — it is narrowed from the session in the handler (CLAUDE.md
+ * convention).
  */
 import { z } from "zod/v4";
 import {
@@ -10,7 +12,7 @@ import {
   type InstrumentId,
 } from "@/lib/mental-health/instruments";
 
-export const assessmentInstrumentEnum = z.enum(["PHQ9", "GAD7"]);
+export const assessmentInstrumentEnum = z.enum(["PHQ9", "GAD7", "WHO5", "SCI"]);
 
 /**
  * Client provenance for an administration. Closed enum so the column can never
@@ -21,12 +23,15 @@ export const assessmentInstrumentEnum = z.enum(["PHQ9", "GAD7"]);
  */
 export const assessmentSourceEnum = z.enum(["WEB", "IOS"]);
 
-const itemAnswer = z.number().int().min(0).max(3);
+// Structural ceiling — the WHO-5's 0–5 scale is the widest. The exact
+// per-instrument ceiling (PHQ/GAD 3, SCI 4) is enforced in the superRefine
+// below, where the instrument is known.
+const itemAnswer = z.number().int().min(0).max(5);
 
 export const createAssessmentSchema = z
   .object({
     instrument: assessmentInstrumentEnum,
-    /** Per-item answers, each 0–3, ordered as the instrument presents them. */
+    /** Per-item answers, ordered as the instrument presents them. */
     items: z.array(itemAnswer).min(1).max(12),
     /** Optional functional-impairment follow-up (not scored into the total). */
     functionalDifficulty: z.number().int().min(0).max(3).optional(),
@@ -55,6 +60,15 @@ export const createAssessmentSchema = z
         message: `${val.instrument} expects exactly ${def.itemCount} item answers`,
       });
     }
+    val.items.forEach((answer, index) => {
+      if (answer > def.itemMax) {
+        ctx.addIssue({
+          code: "custom",
+          path: ["items", index],
+          message: `${val.instrument} answers range 0–${def.itemMax}`,
+        });
+      }
+    });
   });
 
 export const listAssessmentsSchema = z.object({