diff --git a/e2e/settings-score.spec.ts b/e2e/settings-score.spec.ts
index f8e57e90a..5980f258c 100644
--- a/e2e/settings-score.spec.ts
+++ b/e2e/settings-score.spec.ts
@@ -13,12 +13,12 @@ import { healthScoreAlgorithmItemKey } from "@/lib/daily/priority-item-key";
  * at any width and in any locale (only the copy assertions read English, and
  * the suite pins the English locale through the storage state).
  *
- * The refusal case is driven through the REAL write. Deselecting down to
- * activity and wellbeing genuinely fails the server's breadth rule, and a
- * refused write persists nothing, so the case leaves the shared account
- * exactly as it found it. Mocking the 422 would have proved that the page
- * can render a message, not that the rule is enforced or that the page reads
- * the reason the server actually sends.
+ * The refusal case is driven through the REAL write. Deselecting every
+ * pillar genuinely fails the server's breadth rule, and a refused write
+ * persists nothing, so the case leaves the shared account exactly as it
+ * found it. Mocking the 422 would have proved that the page can render a
+ * message, not that the rule is enforced or that the page reads the reason
+ * the server actually sends.
  *
  * The analytics read IS mocked, because it is the page's secondary read and
  * the states it drives — waiting for data, safety signposting — depend on
@@ -47,7 +47,7 @@ function scoreReport() {
     provenance,
   });
   return {
-    composite: insufficient("three_domains_required"),
+    composite: insufficient("no_usable_data"),
     pillars: [
       {
         id: "LIPIDS",
@@ -237,16 +237,16 @@ test.describe("Settings → Health Score", () => {
     const card = page.locator('[data-slot="score-config-card"]');
     await settleBeforeMeasure(page, card);
 
-    // Start from everything, then take out every pillar except activity and
-    // wellbeing: two areas of health and no physical measurement, which the
-    // server refuses.
+    // v1.38 — this case used to deselect down to activity and wellbeing,
+    // which the server refused as two areas with no physical
+    // measurement. That selection saves and scores now, so it no longer
+    // exercises a refusal at all. Take every pillar out instead: the
+    // empty selection is the one the scorer genuinely cannot answer, and
+    // it is what this spec exists to prove is enforced server-side.
     await page.locator('[data-slot="score-config-preset-all"]').click();
-    const keep = new Set(["ACTIVITY", "WELLBEING"]);
     const rows = page.locator('[data-slot="score-pillar-row"]');
     for (let index = 0; index < (await rows.count()); index += 1) {
       const row = rows.nth(index);
-      const pillar = await row.getAttribute("data-pillar");
-      if (!pillar || keep.has(pillar)) continue;
       if ((await row.getAttribute("data-counts")) === "false") continue;
       await row.locator('[data-slot="score-pillar-switch"]').click();
     }
@@ -258,8 +258,8 @@ test.describe("Settings → Health Score", () => {
     await expect(refusal).toHaveAttribute("role", "alert");
     // The server's machine reason, rendered as a sentence a person can act
     // on, not as an error code and not as the server's English fallback.
-    await expect(refusal).toContainText("physical measurement");
-    await expect(refusal).not.toContainText("_required");
+    await expect(refusal).toContainText("at least one area of health");
+    await expect(refusal).not.toContainText("_selected");
   });
 
   test("keeps the content column the same width as its neighbours", async ({
diff --git a/src/__tests__/health-score-basis-additive-contract.test.ts b/src/__tests__/health-score-basis-additive-contract.test.ts
new file mode 100644
index 000000000..fd128173c
--- /dev/null
+++ b/src/__tests__/health-score-basis-additive-contract.test.ts
@@ -0,0 +1,190 @@
+/**
+ * v1.38 — `scoreBasis` is additive on every wire it rides, and stays so.
+ *
+ * The block is new on three shapes that already ship: the full score
+ * report's composite, the dashboard snapshot's flattened hero block, and
+ * the daily digest's score. All three are `additionalProperties: false`,
+ * and two of the three are served out of a CACHE — a snapshot or digest
+ * written before this release has no way to grow a field. Declare
+ * `scoreBasis` as required on any of them and every cached payload in
+ * existence becomes invalid against the document that describes it on
+ * the day the document is published, with nothing failing anywhere: the
+ * generator is happy, `openapi:check` is happy, and the only symptom is
+ * a strict client-side decoder rejecting real responses.
+ *
+ * That is the class this file pins. Every carrier must declare the
+ * property (so a registry edit that drops it is not a green pass), must
+ * NOT list it in `required`, and must point at the one shared component
+ * rather than a fourth hand-rolled copy of the same object. The fields
+ * that shipped before it stay required, because "additive" is a claim
+ * about both directions.
+ *
+ * The document is BUILT rather than read off disk, the way the sharing
+ * components guard does it: `scripts/check-openapi.ts` already pins
+ * `docs/api/openapi.yaml` to exactly this document and CI fails on
+ * drift, so building it here checks the same artifact without parsing
+ * two megabytes of YAML.
+ *
+ * ## Mutation check
+ *
+ * Drop `.optional()` from any of the three registry declarations and the
+ * matching `required` assertion goes red. Delete a declaration entirely
+ * and the presence assertion goes red first.
+ */
+import { describe, expect, it } from "vitest";
+
+import { buildOpenApiDocument } from "@/lib/openapi/registry";
+
+type Schema = {
+  type?: string;
+  properties?: Record<string, Schema>;
+  required?: string[];
+  items?: Schema;
+  anyOf?: Schema[];
+  allOf?: Schema[];
+  oneOf?: Schema[];
+  $ref?: string;
+  description?: string;
+  enum?: string[];
+  nullable?: boolean;
+};
+
+const doc = buildOpenApiDocument() as unknown as {
+  components?: { schemas?: Record<string, Schema> };
+};
+const schemas = doc.components?.schemas ?? {};
+
+const BASIS_REF = "#/components/schemas/HealthScoreBasis";
+
+/**
+ * Walk a schema tree and collect every object that declares a
+ * `scoreBasis` property, wherever it is nested.
+ *
+ * Written as a walk rather than a path lookup on purpose: the three
+ * shapes sit at three very different depths (a component's union arm, a
+ * deeply nested snapshot object, a nullable digest member), and a
+ * hand-written path per surface is a fourth restatement of the contract
+ * that can rot without anybody noticing.
+ */
+function objectsCarryingScoreBasis(root: unknown): Schema[] {
+  const found: Schema[] = [];
+  const seen = new Set<unknown>();
+  const visit = (node: unknown): void => {
+    if (node === null || typeof node !== "object") return;
+    if (seen.has(node)) return;
+    seen.add(node);
+    if (Array.isArray(node)) {
+      for (const child of node) visit(child);
+      return;
+    }
+    const schema = node as Schema;
+    if (schema.properties && "scoreBasis" in schema.properties) {
+      found.push(schema);
+    }
+    for (const value of Object.values(node as Record<string, unknown>)) {
+      visit(value);
+    }
+  };
+  visit(root);
+  return found;
+}
+
+describe("the score basis is published, and published as optional", () => {
+  it("declares the shared component once", () => {
+    const basis = schemas.HealthScoreBasis;
+    expect(
+      basis,
+      "HealthScoreBasis is not a published component",
+    ).toBeDefined();
+    expect(Object.keys(basis?.properties ?? {}).sort()).toEqual([
+      "domains",
+      "physiological",
+      "recommended",
+      "tier",
+    ]);
+    // The tier vocabulary is the whole label. A client reads it verbatim,
+    // so the members are pinned rather than left to the enum's shape.
+    expect(basis?.properties?.tier?.enum).toEqual([
+      "full",
+      "partial",
+      "minimal",
+    ]);
+    // Inside the component the four fields ARE required — the block is
+    // all-or-nothing. Optionality lives on the shapes that carry it, not
+    // on its own members, and confusing the two is how a "yes it is
+    // optional" answer ends up being about the wrong object.
+    expect([...(basis?.required ?? [])].sort()).toEqual([
+      "domains",
+      "physiological",
+      "recommended",
+      "tier",
+    ]);
+  });
+
+  it("is carried by every score-bearing shape, and required by none", () => {
+    const carriers = objectsCarryingScoreBasis(schemas);
+    const composites = carriers.filter(
+      (carrier) => carrier.properties?.scoreBasis?.$ref === BASIS_REF,
+    );
+
+    // The non-zero control, and it does double duty. Three surfaces carry
+    // a composite score — the report's composite, the dashboard
+    // snapshot's hero block, the daily digest's score — and each is
+    // counted only if it points at the shared component, so an inlined
+    // fourth copy of the object drops the count rather than passing as a
+    // carrier. A walk that stopped matching reports zero and fails,
+    // instead of reporting a green run over nothing.
+    expect(composites.length).toBeGreaterThanOrEqual(3);
+
+    for (const carrier of carriers) {
+      expect(carrier.required ?? []).not.toContain("scoreBasis");
+    }
+  });
+
+  it("does not confuse the composite's basis with a pillar's", () => {
+    // `scoreBasis` is an older field name on `PillarValue`, where blood
+    // pressure uses it to say which of its two axes produced the number.
+    // Same key, different object, on a shape that also rides the score
+    // report — so the walk above finds it, and the assertion that every
+    // carrier `$ref`s the composite component would have been wrong.
+    // Pinned here so a future reader does not "fix" that by widening the
+    // composite component to swallow the pillar's field.
+    const carriers = objectsCarryingScoreBasis(schemas);
+    const pillarBasis = carriers.filter(
+      (carrier) => carrier.properties?.scoreBasis?.$ref !== BASIS_REF,
+    );
+    expect(pillarBasis.length).toBeGreaterThan(0);
+    for (const carrier of pillarBasis) {
+      expect(carrier.properties?.scoreBasis?.type).toBe("object");
+      expect(
+        Object.keys(carrier.properties?.scoreBasis?.properties ?? {}),
+      ).toContain("axis");
+    }
+  });
+
+  it("keeps the fields that shipped before it required", () => {
+    // The other half of "additive": adding a field must not have
+    // loosened anything that was already load-bearing. `composition` and
+    // `configured` are read by iOS on the composite, and a silently
+    // optional `composition` would be a contract break wearing the
+    // additive change's clothes.
+    const composite = schemas.DerivedHealthScoreComposite;
+    expect(composite, "DerivedHealthScoreComposite is missing").toBeDefined();
+    const okArm = (composite?.anyOf ?? composite?.oneOf ?? []).find((arm) =>
+      arm.properties?.value?.properties
+        ? "scoreBasis" in arm.properties.value.properties
+        : false,
+    );
+    expect(okArm, "the ok arm of the composite is missing").toBeDefined();
+    const value = okArm?.properties?.value;
+    expect([...(value?.required ?? [])].sort()).toEqual([
+      "band",
+      "bandSetter",
+      "composition",
+      "configured",
+      "noiseFloor",
+      "score",
+      "scoreVersion",
+    ]);
+  });
+});
diff --git a/src/app/api/auth/me/health-score-config/__tests__/route.test.ts b/src/app/api/auth/me/health-score-config/__tests__/route.test.ts
index ae1f5db38..75d4ff20f 100644
--- a/src/app/api/auth/me/health-score-config/__tests__/route.test.ts
+++ b/src/app/api/auth/me/health-score-config/__tests__/route.test.ts
@@ -258,45 +258,64 @@ describe("PATCH /api/auth/me/health-score-config", () => {
   });
 });
 
+/**
+ * v1.38 — what the write still refuses, after the breadth floor became a
+ * recommendation.
+ *
+ * Two of the three refusals this block used to pin are gone. The route
+ * turned away `["ACTIVITY", "WELLBEING"]` with
+ * `measured_physiological_domain_required` and the cardiometabolic
+ * triple with `three_domains_required`, both on the ground that the
+ * selection could not produce a score. It can now — the scorer computes
+ * from whatever is readable and labels how broad the set was — and a
+ * write that kept refusing what the read is willing to serve would be
+ * the two layers disagreeing, which is the drift the shared rule exists
+ * to prevent. So those two assertions are inverted to acceptances.
+ *
+ * The empty selection stays refused, and that case is why this is a
+ * change of rule rather than a removal of one.
+ */
 describe("PATCH — the breadth rule", () => {
-  it("refuses activity and wellbeing alone, in words a person can act on", async () => {
+  it("accepts activity and wellbeing alone, and stores them", async () => {
     vi.mocked(getSession).mockResolvedValue(SESSION_OK as never);
     primeUser(null);
 
     const res = await (PATCH as (r: Request) => Promise<Response>)(
       mkPatch({ pillars: ["ACTIVITY", "WELLBEING"] }),
     );
-    expect(res.status).toBe(422);
-    const env = (await res.json()) as {
-      error: string;
-      meta?: { errorCode?: string; reason?: string };
-    };
-    expect(env.meta?.errorCode).toBe("health_score_config.too_narrow");
-    expect(env.meta?.reason).toBe("measured_physiological_domain_required");
-    expect(env.error).toContain("at least one physical measurement");
-    expect(prisma.user.update).not.toHaveBeenCalled();
-    expect(prisma.user.updateMany).not.toHaveBeenCalled();
-    expect(invalidateUserHealthScore).not.toHaveBeenCalled();
+    expect(res.status).toBe(200);
+    expect(prisma.user.update).toHaveBeenCalledTimes(1);
+    expect(invalidateUserHealthScore).toHaveBeenCalledWith("user-1");
   });
 
-  it("refuses the cardiometabolic triple, which is three pillars in one area", async () => {
+  it("accepts the cardiometabolic triple, which is three pillars in one area", async () => {
     vi.mocked(getSession).mockResolvedValue(SESSION_OK as never);
     primeUser(null);
 
     const res = await (PATCH as (r: Request) => Promise<Response>)(
       mkPatch({ pillars: ["BLOOD_PRESSURE", "GLYCAEMIA", "LIPIDS"] }),
     );
-    expect(res.status).toBe(422);
-    const env = (await res.json()) as {
-      error: string;
-      meta?: { reason?: string };
-    };
-    expect(env.meta?.reason).toBe("three_domains_required");
-    expect(env.error).toContain("three different areas");
-    expect(prisma.user.update).not.toHaveBeenCalled();
+    expect(res.status).toBe(200);
+    expect(prisma.user.update).toHaveBeenCalledTimes(1);
+  });
+
+  it("accepts a single pillar", async () => {
+    // The narrowest selection that can still be scored, and the boundary
+    // the one surviving refusal sits against.
+    vi.mocked(getSession).mockResolvedValue(SESSION_OK as never);
+    primeUser(null);
+
+    const res = await (PATCH as (r: Request) => Promise<Response>)(
+      mkPatch({ pillars: ["ACTIVITY"] }),
+    );
+    expect(res.status).toBe(200);
+    expect(prisma.user.update).toHaveBeenCalledTimes(1);
   });
 
   it("refuses an empty selection rather than storing a score that cannot exist", async () => {
+    // The counter-case. A write that accepted everything would have
+    // stopped enforcing anything, and this is the one selection the
+    // scorer genuinely cannot answer.
     vi.mocked(getSession).mockResolvedValue(SESSION_OK as never);
     primeUser(null);
 
@@ -304,10 +323,19 @@ describe("PATCH — the breadth rule", () => {
       mkPatch({ pillars: [] }),
     );
     expect(res.status).toBe(422);
+    const env = (await res.json()) as {
+      error: string;
+      meta?: { errorCode?: string; reason?: string };
+    };
+    expect(env.meta?.errorCode).toBe("health_score_config.too_narrow");
+    expect(env.meta?.reason).toBe("no_pillars_selected");
+    expect(env.error).toContain("at least one area of health");
     expect(prisma.user.update).not.toHaveBeenCalled();
+    expect(prisma.user.updateMany).not.toHaveBeenCalled();
+    expect(invalidateUserHealthScore).not.toHaveBeenCalled();
   });
 
-  it("accepts the smallest selection that clears the rule", async () => {
+  it("accepts a three-area selection", async () => {
     vi.mocked(getSession).mockResolvedValue(SESSION_OK as never);
     primeUser(null);
 
@@ -449,9 +477,9 @@ describe("the published contract matches what the route serves", () => {
       }
     };
 
-    // Too narrow, both reasons.
-    await record({ pillars: ["ACTIVITY"] });
-    await record({ pillars: ["BLOOD_PRESSURE", "GLYCAEMIA", "LIPIDS"] });
+    // Too narrow. One reason since v1.38, because one selection is: the
+    // empty one.
+    await record({ pillars: [] });
     // Body that fails validation.
     await record({ pillars: ["NOT_A_PILLAR"] });
     // Present-but-unparseable base token.
diff --git a/src/components/insights/__tests__/health-score-card.test.tsx b/src/components/insights/__tests__/health-score-card.test.tsx
index 41283bd96..e97471b1c 100644
--- a/src/components/insights/__tests__/health-score-card.test.tsx
+++ b/src/components/insights/__tests__/health-score-card.test.tsx
@@ -207,7 +207,7 @@ function report(overrides: Partial<HealthScoreReport> = {}): HealthScoreReport {
       status: "insufficient",
       coverage,
       provenance,
-      reason: "three_domains_required",
+      reason: "no_usable_data",
     },
     pillars: [BLOOD_PRESSURE, ACTIVITY_BELOW_FLOOR],
     delta: null,
diff --git a/src/components/settings/__tests__/score-refusal-consumer-guard.test.ts b/src/components/settings/__tests__/score-refusal-consumer-guard.test.ts
index 2a864de77..d20a4466e 100644
--- a/src/components/settings/__tests__/score-refusal-consumer-guard.test.ts
+++ b/src/components/settings/__tests__/score-refusal-consumer-guard.test.ts
@@ -107,9 +107,13 @@ const routeReasons = objectKeys(parse(ROUTE_FILE), "BREADTH_REFUSAL");
 
 describe("every refusal the rule can give reaches the reader", () => {
   it("reads the rule's own list rather than a copy of it", () => {
-    // A matcher that finds nothing agrees with everything.
+    // A matcher that finds nothing agrees with everything. The anchor
+    // moved from `three_domains_required` to `no_pillars_selected` in
+    // v1.38: three areas of health stopped being the price of a score,
+    // so the write stopped refusing narrow selections and the only
+    // refusal left is the empty one.
     expect(ruleReasons.length).toBeGreaterThan(0);
-    expect(ruleReasons).toContain("three_domains_required");
+    expect(ruleReasons).toContain("no_pillars_selected");
   });
 
   it("gives the route a sentence for each of them", () => {
diff --git a/src/lib/analytics/score/__tests__/breadth.test.ts b/src/lib/analytics/score/__tests__/breadth.test.ts
index 864f07476..8c35cefbe 100644
--- a/src/lib/analytics/score/__tests__/breadth.test.ts
+++ b/src/lib/analytics/score/__tests__/breadth.test.ts
@@ -1,20 +1,37 @@
 /**
- * v1.35.0 — the breadth rule, and the proof that both layers apply the
- * same one.
+ * v1.38 — the breadth rule, now a grading rather than a gate, and the
+ * proof that both layers still read the same one.
  *
- * The settings write refuses a selection that cannot produce a score;
- * the scorer refuses to produce one from a set that fails the same rule.
- * Two layers, on purpose. The danger in two layers is that they drift,
- * so the last block below drives the real `computeComposite` and asserts
- * it refuses exactly the sets `evaluateScoreBreadth` refuses, with the
- * same reason.
+ * This file used to pin the two refusals (`three_domains_required`,
+ * `measured_physiological_domain_required`) as the rule's whole output.
+ * They are gone: three areas of health is what the score RECOMMENDS, and
+ * a set below it is scored and labelled instead of refused. So the cases
+ * that asserted a refusal now assert a TIER, which is the same question
+ * asked of a rule that answers it differently.
+ *
+ * What survives unchanged is the reason the file exists. Two layers
+ * apply the rule — the settings write and the scorer — and two layers
+ * drift. The middle block below drives the real `computeComposite` and
+ * asserts it produces a score for exactly the sets the rule admits, and
+ * refuses exactly the one it does not.
+ *
+ * The last block is the counter-case, and it is the one that would catch
+ * this change going too far. A rule that has stopped refusing anything
+ * is not a graded rule, it is a deleted one, so the empty set must still
+ * come back refused — with a reason, from a verdict that carries no
+ * tier — and the composite must still say `no_usable_data` rather than
+ * inventing a score out of nothing.
  */
 import { describe, expect, it } from "vitest";
 
 import { buildOk, deriveCoverage } from "@/lib/insights/derived/coverage";
 import type { Derived } from "@/lib/insights/derived/types";
 
-import { evaluateScoreBreadth } from "../breadth";
+import {
+  evaluateScoreBreadth,
+  SCORE_RECOMMENDED_DOMAINS,
+  type ScoreBreadthTier,
+} from "../breadth";
 import { computeComposite } from "../composite";
 import {
   SCORE_PILLAR_DOMAINS,
@@ -68,77 +85,119 @@ function pillar(id: ScorePillarId, score = 80): ScorePillarResult {
   return { id, domain: SCORE_PILLAR_DOMAINS[id], result };
 }
 
-/** The sets the rule has an opinion about, each with the expected verdict. */
+/**
+ * The sets the rule has an opinion about, each with the tier it should
+ * reach and whether the set carries a physiological measurement.
+ *
+ * `tier: null` means refused. Exactly one case is refused, on purpose:
+ * every other row in this table used to be a refusal too, and each is
+ * now a number somebody gets to see.
+ */
 const CASES: Array<{
   what: string;
   ids: ScorePillarId[];
-  reason: string | null;
+  tier: ScoreBreadthTier | null;
+  physiological: boolean;
 }> = [
-  {
-    what: "the two non-physiological pillars alone",
-    ids: ["ACTIVITY", "WELLBEING"],
-    reason: "measured_physiological_domain_required",
-  },
-  {
-    what: "activity and wellbeing plus nothing measured",
-    ids: ["ACTIVITY"],
-    reason: "measured_physiological_domain_required",
-  },
   {
     what: "an empty selection",
     ids: [],
-    reason: "measured_physiological_domain_required",
+    tier: null,
+    physiological: false,
   },
   {
-    what: "the whole cardiometabolic triple, which is one domain",
+    what: "activity alone, which measures nothing physiological",
+    ids: ["ACTIVITY"],
+    tier: "minimal",
+    physiological: false,
+  },
+  {
+    what: "the two non-physiological pillars together",
+    ids: ["ACTIVITY", "WELLBEING"],
+    tier: "partial",
+    physiological: false,
+  },
+  {
+    what: "the whole cardiometabolic triple, which is one area",
     ids: ["BLOOD_PRESSURE", "GLYCAEMIA", "LIPIDS"],
-    reason: "three_domains_required",
+    tier: "minimal",
+    physiological: true,
   },
   {
-    what: "two domains with a physiological pillar",
+    what: "one physiological pillar alone",
+    ids: ["BLOOD_PRESSURE"],
+    tier: "minimal",
+    physiological: true,
+  },
+  {
+    what: "two areas with a physiological pillar",
     ids: ["BLOOD_PRESSURE", "ACTIVITY"],
-    reason: "three_domains_required",
+    tier: "partial",
+    physiological: true,
   },
   {
-    what: "three domains including a physiological pillar",
+    what: "three areas including a physiological pillar",
     ids: ["BLOOD_PRESSURE", "ACTIVITY", "SLEEP"],
-    reason: null,
+    tier: "full",
+    physiological: true,
   },
   {
-    what: "three domains where two pillars share one",
+    what: "three areas where two pillars share one",
     ids: ["BLOOD_PRESSURE", "LIPIDS", "ACTIVITY", "SLEEP"],
-    reason: null,
+    tier: "full",
+    physiological: true,
+  },
+  {
+    what: "every pillar",
+    ids: [...SCORE_PILLAR_IDS],
+    tier: "full",
+    physiological: true,
   },
-  { what: "every pillar", ids: [...SCORE_PILLAR_IDS], reason: null },
 ];
 
 describe("evaluateScoreBreadth", () => {
-  for (const { what, ids, reason } of CASES) {
-    it(`${reason ? "refuses" : "accepts"} ${what}`, () => {
+  for (const { what, ids, tier, physiological } of CASES) {
+    it(`${tier === null ? "refuses" : `grades ${tier} for`} ${what}`, () => {
       const verdict = evaluateScoreBreadth(ids);
-      expect(verdict.ok).toBe(reason === null);
-      expect(verdict.reason).toBe(reason);
+      expect(verdict.ok).toBe(tier !== null);
+      expect(verdict.tier).toBe(tier);
+      expect(verdict.physiological).toBe(physiological);
+      expect(verdict.reason).toBe(tier === null ? "no_pillars_selected" : null);
     });
   }
 
-  it("names the missing physiological measure before the missing domain", () => {
-    // Three domains, none of them a physiological measure is impossible
-    // with the current registry, so the precedence shows on the set that
-    // fails both: one non-physiological pillar, one domain.
-    expect(evaluateScoreBreadth(["ACTIVITY"]).reason).toBe(
-      "measured_physiological_domain_required",
-    );
+  it("grades on distinct areas, not on how many pillars were named", () => {
+    // The whole point of the domain map. Three pillars, one area: this is
+    // the set the old rule refused outright and the set most likely to be
+    // graded `full` by a client that counts `composition` instead.
+    const triple = evaluateScoreBreadth([
+      "BLOOD_PRESSURE",
+      "GLYCAEMIA",
+      "LIPIDS",
+    ]);
+    expect(triple.tier).toBe("minimal");
+    expect(triple.domains).toEqual(["cardiometabolic"]);
   });
 
-  it("reports the distinct domains the set spans", () => {
+  it("puts the recommendation at three areas and reaches full there", () => {
+    expect(SCORE_RECOMMENDED_DOMAINS).toBe(3);
     expect(
-      evaluateScoreBreadth(["BLOOD_PRESSURE", "GLYCAEMIA", "LIPIDS"]).domains,
-    ).toEqual(["cardiometabolic"]);
+      evaluateScoreBreadth(["BLOOD_PRESSURE", "ACTIVITY", "SLEEP"]).domains,
+    ).toHaveLength(SCORE_RECOMMENDED_DOMAINS);
+  });
+
+  it("reports a missing physiological measure without withholding the score", () => {
+    // The old rule's sharpest edge, inverted on purpose: activity alone
+    // used to be told "no score for you" and is now told what its score
+    // rests on. `physiological: false` is the whole of that caveat.
+    const verdict = evaluateScoreBreadth(["ACTIVITY"]);
+    expect(verdict.ok).toBe(true);
+    expect(verdict.physiological).toBe(false);
   });
 });
 
-describe("the scorer refuses exactly what the write refuses", () => {
-  for (const { what, ids } of CASES) {
+describe("the scorer grades exactly what the rule grades", () => {
+  for (const { what, ids, tier, physiological } of CASES) {
     it(`agrees on ${what}`, () => {
       const composite = computeComposite({
         pillars: ids.map((id) => pillar(id)),
@@ -148,11 +207,101 @@ describe("the scorer refuses exactly what the write refuses", () => {
       });
       const verdict = evaluateScoreBreadth(ids);
       expect(composite.status).toBe(verdict.ok ? "ok" : "insufficient");
-      if (composite.status === "insufficient") {
-        expect(composite.reason).toBe(verdict.reason);
+      if (composite.status === "ok") {
+        expect(composite.value.scoreBasis).toEqual({
+          domains: verdict.domains.length,
+          recommended: SCORE_RECOMMENDED_DOMAINS,
+          tier,
+          physiological,
+        });
       }
     });
   }
+
+  it("computes the same number at every tier", () => {
+    // No discount for the pillars somebody does not track. A mean of 80
+    // and 60 is 70 whether it is drawn from two areas or five, because
+    // any other answer would be a target nobody set.
+    const narrow = computeComposite({
+      pillars: [pillar("BLOOD_PRESSURE", 80), pillar("ACTIVITY", 60)],
+      availablePillars: ["BLOOD_PRESSURE", "ACTIVITY"],
+      asOf: NOW,
+      configured: false,
+    });
+    const broad = computeComposite({
+      pillars: [
+        pillar("BLOOD_PRESSURE", 80),
+        pillar("ACTIVITY", 60),
+        pillar("SLEEP", 70),
+      ],
+      availablePillars: ["BLOOD_PRESSURE", "ACTIVITY", "SLEEP"],
+      asOf: NOW,
+      configured: false,
+    });
+    expect(narrow.status).toBe("ok");
+    expect(broad.status).toBe("ok");
+    if (narrow.status !== "ok" || broad.status !== "ok") return;
+    expect(narrow.value.score).toBe(70);
+    expect(broad.value.score).toBe(70);
+    expect(narrow.value.scoreBasis?.tier).toBe("partial");
+    expect(broad.value.scoreBasis?.tier).toBe("full");
+  });
+});
+
+describe("the refusal that is left still refuses", () => {
+  // A rule that grades everything has stopped being a rule. These are the
+  // assertions that fail if the grading is widened until nothing can be
+  // turned away.
+  it("gives the empty set a reason and no tier", () => {
+    const verdict = evaluateScoreBreadth([]);
+    expect(verdict.ok).toBe(false);
+    if (verdict.ok) return;
+    expect(verdict.reason).toBe("no_pillars_selected");
+    expect(verdict.tier).toBeNull();
+    expect(verdict.domains).toEqual([]);
+  });
+
+  it("refuses a composite whose pillars are all insufficient", () => {
+    // The realistic shape of nothing: pillars are SELECTED and graded,
+    // every one of them came back short. An empty `availablePillars`
+    // array would prove less, because a set nobody chose is trivially
+    // empty; this is an account that chose four and has data for none.
+    const selection: ScorePillarId[] = [
+      "BLOOD_PRESSURE",
+      "ACTIVITY",
+      "SLEEP",
+      "WELLBEING",
+    ];
+    const composite = computeComposite({
+      pillars: selection.map((id) => ({
+        id,
+        domain: SCORE_PILLAR_DOMAINS[id],
+        result: {
+          status: "insufficient",
+          coverage: deriveCoverage({
+            requiredInputs: 1,
+            presentInputs: 0,
+            historyDays: 0,
+            missing: [id],
+            fullHistoryDays: 28,
+          }).coverage,
+          provenance: {
+            inputs: [],
+            source: "none",
+            windowDays: 28,
+            computedAt: NOW.toISOString(),
+          },
+          reason: "below_day_floor_or_stale",
+        },
+      })),
+      availablePillars: selection,
+      asOf: NOW,
+      configured: false,
+    });
+    expect(composite.status).toBe("insufficient");
+    if (composite.status !== "insufficient") return;
+    expect(composite.reason).toBe("no_usable_data");
+  });
 });
 
 describe("the pillar-to-domain map", () => {
@@ -163,8 +312,9 @@ describe("the pillar-to-domain map", () => {
   });
 
   it("keeps the three cardiometabolic pillars in one domain", () => {
-    // The triple-count is the reason a five-pillar selection can still
-    // fail the rule, so it is pinned rather than left to the map's shape.
+    // The triple-count is the reason a four-pillar selection can still be
+    // a one-area score, so it is pinned rather than left to the map's
+    // shape.
     expect(SCORE_PILLAR_DOMAINS.BLOOD_PRESSURE).toBe("cardiometabolic");
     expect(SCORE_PILLAR_DOMAINS.GLYCAEMIA).toBe("cardiometabolic");
     expect(SCORE_PILLAR_DOMAINS.LIPIDS).toBe("cardiometabolic");
diff --git a/src/lib/analytics/score/__tests__/composite.test.ts b/src/lib/analytics/score/__tests__/composite.test.ts
index 2a7063fd7..e87f00930 100644
--- a/src/lib/analytics/score/__tests__/composite.test.ts
+++ b/src/lib/analytics/score/__tests__/composite.test.ts
@@ -135,8 +135,10 @@ describe("the band the mean alone gives", () => {
   it("moved the method version with it", () => {
     // A stored day keeps the band it was shown under, and the notice key
     // carries this number, so each account hears once that the rules
-    // moved. A threshold edit without a version bump is a silent one.
-    expect(SCORE_VERSION).toBeGreaterThan(2);
+    // moved. A threshold edit without a version bump is a silent one, and
+    // so is an eligibility edit: v1.38 widened who gets a score at all,
+    // which is why this floor moved from 2 to 3.
+    expect(SCORE_VERSION).toBeGreaterThan(3);
   });
 });
 
@@ -198,21 +200,43 @@ describe("the worst pillar still holds the band down", () => {
 });
 
 describe("reference-score composite", () => {
-  it("requires three domains and one measured physiological domain", () => {
-    const tooNarrow = evaluation(
+  it("scores two areas of health, and says it was two", () => {
+    // Inverted from the v1.35 pin, which asserted this exact pair came
+    // back `insufficient`. Three areas is the recommendation now, so a
+    // person with two gets their number and a basis block that does not
+    // overstate it. Note `physiological: false` — neither activity nor
+    // wellbeing is a measurement, and the old rule refused the set on
+    // that ground alone.
+    const partial = evaluation(
       [pillar("ACTIVITY", 90), pillar("WELLBEING", 80)],
       NOW,
     );
-    expect(tooNarrow.status).toBe("insufficient");
+    expect(partial.status).toBe("ok");
+    if (partial.status !== "ok") return;
+    expect(partial.value.score).toBe(85);
+    expect(partial.value.scoreBasis).toEqual({
+      domains: 2,
+      recommended: 3,
+      tier: "partial",
+      physiological: false,
+    });
 
-    const eligible = evaluation(
+    const full = evaluation(
       [pillar("ACTIVITY", 90), pillar("WELLBEING", 80), pillar("SLEEP", 70)],
       NOW,
     );
-    expect(eligible.status).toBe("ok");
+    expect(full.status).toBe("ok");
+    if (full.status !== "ok") return;
+    expect(full.value.scoreBasis?.tier).toBe("full");
+    expect(full.value.scoreBasis?.physiological).toBe(true);
   });
 
   it("reports breadth coverage as distinct eligible domains", () => {
+    // Same fixture as the v1.35 version — four pillars, two areas — and
+    // the same coverage arithmetic. What changed is the outcome. The
+    // fraction used to be a floor every scored account had already
+    // cleared; it is a real moving number on a scored account now, which
+    // is what makes the coverage meter say something.
     const result = evaluation(
       [
         pillar("BLOOD_PRESSURE", 90),
@@ -223,12 +247,52 @@ describe("reference-score composite", () => {
       NOW,
     );
 
-    expect(result.status).toBe("insufficient");
+    expect(result.status).toBe("ok");
     expect(result.coverage.requiredInputs).toBe(3);
     expect(result.coverage.presentInputs).toBe(2);
-    if (result.status === "insufficient") {
-      expect(result.reason).toBe("three_domains_required");
-    }
+    if (result.status !== "ok") return;
+    expect(result.value.scoreBasis).toEqual({
+      domains: 2,
+      recommended: 3,
+      tier: "partial",
+      physiological: true,
+    });
+    // The narrower set does not read as fully confident, and nothing new
+    // was built for that: the existing coverage blend already does it.
+    expect(result.confidence.score).toBeLessThan(100);
+  });
+
+  it("scores one area of health, at the tier that says so", () => {
+    // The bottom tier boundary, on the shape most likely to fool a
+    // client that counts `composition` instead of areas: three pillars,
+    // one area.
+    const result = evaluation(
+      [
+        pillar("BLOOD_PRESSURE", 90),
+        pillar("GLYCAEMIA", 84),
+        pillar("LIPIDS", 81),
+      ],
+      NOW,
+    );
+    expect(result.status).toBe("ok");
+    if (result.status !== "ok") return;
+    expect(result.value.score).toBe(85);
+    expect(result.value.composition).toHaveLength(3);
+    expect(result.value.scoreBasis).toEqual({
+      domains: 1,
+      recommended: 3,
+      tier: "minimal",
+      physiological: true,
+    });
+  });
+
+  it("refuses when not one pillar is usable, and says why", () => {
+    // The counter-case. Grading instead of gating is only honest while
+    // something is still turned away; this is the something.
+    const result = evaluation([], NOW);
+    expect(result.status).toBe("insufficient");
+    if (result.status !== "insufficient") return;
+    expect(result.reason).toBe("no_usable_data");
   });
 
   it("uses equal weights in registry order", () => {
diff --git a/src/lib/analytics/score/__tests__/composition-source.test.ts b/src/lib/analytics/score/__tests__/composition-source.test.ts
index 288662db5..8d6535509 100644
--- a/src/lib/analytics/score/__tests__/composition-source.test.ts
+++ b/src/lib/analytics/score/__tests__/composition-source.test.ts
@@ -21,9 +21,9 @@
  *    they switched off is not waiting for anything.
  *
  * 3. **One breadth rule, applied twice.** The settings write refuses a
- *    selection that cannot produce a score; the reader refuses to
- *    produce one from a set that fails the same rule. The block at the
- *    bottom drives the REAL reader and asserts its refusal reason is
+ *    selection that cannot produce a score; the reader grades the set it
+ *    resolved through the same rule. The block at the bottom drives the
+ *    REAL reader and asserts the basis it published is
  *    `evaluateScoreBreadth`'s verdict on the reader's own resolved set,
  *    so a second copy of the rule that disagreed would show up here.
  *
@@ -480,10 +480,16 @@ describe("selected and waiting for data versus switched off", () => {
   });
 });
 
-describe("the breadth rule still refuses at read time", () => {
+describe("the breadth rule still grades at read time", () => {
+  // Inverted from the v1.35 pins, which asserted all three of these
+  // recipes came back `insufficient`. Two of them produce a score now.
+  // What the block proves has not moved — the reader publishes the shared
+  // rule's verdict on the reader's own resolved set, so a second copy of
+  // the rule that disagreed would still show up here — but the agreement
+  // is over a tier rather than over a refusal.
   const NARROW: Array<{ what: string; selection: ScorePillarId[] }> = [
     {
-      what: "a recipe that leaves two scoring domains",
+      what: "a recipe that leaves two scoring areas",
       selection: ["ACTIVITY", "ADIPOSITY", "BLOOD_PRESSURE"],
     },
     {
@@ -497,7 +503,7 @@ describe("the breadth rule still refuses at read time", () => {
   ];
 
   for (const { what, selection } of NARROW) {
-    it(`refuses ${what}, with the reason the shared rule gives`, async () => {
+    it(`agrees with the shared rule on ${what}`, async () => {
       const report = await score({
         modules: ALL_MODULES_ON,
         healthScoreConfigJson: recipe(selection),
@@ -508,10 +514,23 @@ describe("the breadth rule still refuses at read time", () => {
         .map((pillar) => pillar.id);
       const verdict = evaluateScoreBreadth(scoring);
 
-      expect(verdict.ok).toBe(false);
-      expect(report.composite.status).toBe("insufficient");
-      if (report.composite.status !== "insufficient") return;
-      expect(report.composite.reason).toBe(verdict.reason);
+      expect(report.composite.status).toBe(verdict.ok ? "ok" : "insufficient");
+      if (report.composite.status === "ok") {
+        // The published basis IS the shared rule's verdict on the
+        // reader's set, not a second count taken on the way out.
+        expect(report.composite.value.scoreBasis?.tier).toBe(verdict.tier);
+        expect(report.composite.value.scoreBasis?.domains).toBe(
+          verdict.domains.length,
+        );
+        expect(report.composite.value.scoreBasis?.physiological).toBe(
+          verdict.physiological,
+        );
+      } else {
+        // The one refusal that survives, reached the honest way: a recipe
+        // whose three pillars all came back without data.
+        expect(verdict.ok).toBe(false);
+        expect(report.composite.reason).toBe("no_usable_data");
+      }
     });
   }
 
diff --git a/src/lib/analytics/score/__tests__/config-change-is-not-a-health-event.test.ts b/src/lib/analytics/score/__tests__/config-change-is-not-a-health-event.test.ts
index df1894fcb..c9316c109 100644
--- a/src/lib/analytics/score/__tests__/config-change-is-not-a-health-event.test.ts
+++ b/src/lib/analytics/score/__tests__/config-change-is-not-a-health-event.test.ts
@@ -246,7 +246,7 @@ import { MODULE_KEYS } from "@/lib/modules/registry";
 
 import { healthScoreConfigFromSelection } from "../config";
 import { computeUserHealthScore } from "../reader";
-import { SCORE_PILLAR_IDS } from "../types";
+import { SCORE_PILLAR_IDS, SCORE_VERSION } from "../types";
 
 /** The recipe as the settings write would have stored it. */
 function recipe(changedAt: Date): unknown {
@@ -523,16 +523,16 @@ describe("a settings change is never narrated as a health event", () => {
     const unconfigured = await computeUserHealthScore(scoreInput(null));
 
     expect(configured.algorithmNotice!.itemKey).toBe(
-      "health_score_algorithm:3:config:3",
+      `health_score_algorithm:${SCORE_VERSION}:config:3`,
     );
     expect(configured.algorithmNotice!.dismissed).toBe(false);
     // An account that never chose keeps the bare method key, with no
     // recipe suffix on it.
     expect(unconfigured.algorithmNotice!.itemKey).toBe(
-      "health_score_algorithm:3",
+      `health_score_algorithm:${SCORE_VERSION}`,
     );
 
-    dismissedKeys.add("health_score_algorithm:3:config:3");
+    dismissedKeys.add(`health_score_algorithm:${SCORE_VERSION}:config:3`);
     expect(
       (await computeUserHealthScore(scoreInput(JUST_CHANGED))).algorithmNotice!
         .dismissed,
@@ -550,7 +550,7 @@ describe("a settings change is never narrated as a health event", () => {
       ),
     );
     expect(next.algorithmNotice!.itemKey).toBe(
-      "health_score_algorithm:3:config:4",
+      `health_score_algorithm:${SCORE_VERSION}:config:4`,
     );
     expect(next.algorithmNotice!.dismissed).toBe(false);
   });
diff --git a/src/lib/analytics/score/__tests__/record.test.ts b/src/lib/analytics/score/__tests__/record.test.ts
index b0b05c480..997ba2e2f 100644
--- a/src/lib/analytics/score/__tests__/record.test.ts
+++ b/src/lib/analytics/score/__tests__/record.test.ts
@@ -301,14 +301,35 @@ describe("building the row", () => {
     expect(draft.composition).not.toContain("ACTIVITY");
   });
 
+  it("records a day built from a single pillar", () => {
+    // Inverted from the v1.35 pin, which used a two-pillar fixture to
+    // assert that a below-the-floor day stored nothing. The floor is
+    // gone, so the day HAS a number and the table has to keep it: an
+    // account that only tracks steps now has a history, and one that
+    // begins on one pillar and widens later has an unbroken series
+    // rather than a hole where its narrow days were.
+    const single = report([pillar("ACTIVITY", 90)]);
+    expect(single.composite.status).toBe("ok");
+    const draft = buildHealthScoreRecord(single, {
+      timezone: "UTC",
+      now: NOW,
+      config: UNCONFIGURED_SCORE_BOUNDARY,
+    });
+    expect(draft).not.toBeNull();
+    if (!draft) return;
+    expect(draft.composite).toBe(90);
+    expect(draft.composition).toEqual(["ACTIVITY"]);
+    expect(draft.pillarScores).toEqual({ ACTIVITY: 90 });
+  });
+
   it("records nothing when the composite did not resolve", () => {
-    // Two domains: below the breadth floor, so there is no number. Absence has
-    // to reach the table as absence — a stored 0 would be a day the person is
-    // told they scored zero.
-    const thin = report([pillar("ACTIVITY", 90), pillar("WELLBEING", 80)]);
-    expect(thin.composite.status).toBe("insufficient");
+    // Absence still has to reach the table as absence — a stored 0 would
+    // be a day the person is told they scored zero. What produces that
+    // absence has narrowed to one case: not one usable pillar.
+    const empty = report([]);
+    expect(empty.composite.status).toBe("insufficient");
     expect(
-      buildHealthScoreRecord(thin, {
+      buildHealthScoreRecord(empty, {
         timezone: "UTC",
         now: NOW,
         config: UNCONFIGURED_SCORE_BOUNDARY,
@@ -383,9 +404,24 @@ describe("writing the row", () => {
     ).toBe("already_recorded");
   });
 
+  it("writes the row for a day that rests on one pillar", async () => {
+    // The other half of the inverted pin: the narrow day does not just
+    // build a draft, it reaches the table.
+    const { db, createMany } = delegate(1);
+    const single = report([pillar("ACTIVITY", 90)]);
+    expect(
+      await recordHealthScore(db, "user-1", single, {
+        timezone: "UTC",
+        now: NOW,
+        config: UNCONFIGURED_SCORE_BOUNDARY,
+      }),
+    ).toBe("written");
+    expect(createMany).toHaveBeenCalledTimes(1);
+  });
+
   it("never touches the database when there is no score to record", async () => {
     const { db, createMany } = delegate(1);
-    const thin = report([pillar("ACTIVITY", 90), pillar("WELLBEING", 80)]);
+    const thin = report([]);
     expect(
       await recordHealthScore(db, "user-1", thin, {
         timezone: "UTC",
diff --git a/src/lib/dashboard/__tests__/snapshot.test.ts b/src/lib/dashboard/__tests__/snapshot.test.ts
index 56b551b16..ce4d4f8a3 100644
--- a/src/lib/dashboard/__tests__/snapshot.test.ts
+++ b/src/lib/dashboard/__tests__/snapshot.test.ts
@@ -87,7 +87,7 @@ vi.mock("@/lib/analytics/score/reader", () => ({
           status: "insufficient" as const,
           coverage,
           provenance,
-          reason: "three_domains_required",
+          reason: "no_usable_data",
         };
     return {
       composite,
diff --git a/src/lib/insights/derived/__tests__/health-score-coverage-contract.test.ts b/src/lib/insights/derived/__tests__/health-score-coverage-contract.test.ts
index 477ece211..6e37121b2 100644
--- a/src/lib/insights/derived/__tests__/health-score-coverage-contract.test.ts
+++ b/src/lib/insights/derived/__tests__/health-score-coverage-contract.test.ts
@@ -25,7 +25,7 @@
 import { describe, expect, it } from "vitest";
 
 import { computeComposite } from "@/lib/analytics/score/composite";
-import { SCORE_MIN_ELIGIBLE_DOMAINS } from "@/lib/analytics/score/breadth";
+import { SCORE_RECOMMENDED_DOMAINS } from "@/lib/analytics/score/breadth";
 import {
   healthScoreConfigFromSelection,
   resolveHealthScoreConfig,
@@ -154,7 +154,7 @@ describe("Health Score coverage contract", () => {
     expect(composite.coverage.requiredInputs).not.toBe(SCORE_PILLAR_IDS.length);
     // The denominator is the breadth rule applied to the person's own set,
     // so it can never exceed what they chose to count.
-    expect(composite.coverage.requiredInputs).toBe(SCORE_MIN_ELIGIBLE_DOMAINS);
+    expect(composite.coverage.requiredInputs).toBe(SCORE_RECOMMENDED_DOMAINS);
     expect(composite.coverage.requiredInputs).toBeLessThanOrEqual(
       selection.length,
     );