diff --git a/docs/api/openapi.yaml b/docs/api/openapi.yaml
index 63590ac05..9fbc47346 100644
--- a/docs/api/openapi.yaml
+++ b/docs/api/openapi.yaml
@@ -555,10 +555,7 @@ paths:
                   type: string
                   enum:
                     - MANUAL
-                    - WITHINGS
-                    - IMPORT
                     - APPLE_HEALTH
-                    - COMPUTED
                 glucoseContext:
                   type: string
                   enum:
diff --git a/src/lib/validations/__tests__/measurement.test.ts b/src/lib/validations/__tests__/measurement.test.ts
index 1ab1bca1a..3b95a933e 100644
--- a/src/lib/validations/__tests__/measurement.test.ts
+++ b/src/lib/validations/__tests__/measurement.test.ts
@@ -287,34 +287,49 @@ describe("measurement validation", () => {
       expect(validateMeasurementRange("RECOVERY_SCORE", 101)).not.toBeNull();
     });
 
-    it("rejects the server-owned COMPUTED source on a client write", () => {
-      const parsed = createMeasurementSchema.safeParse({
-        type: "RECOVERY_SCORE",
-        value: 72,
-        measuredAt: "2026-06-02T12:00:00Z",
-        source: "COMPUTED",
-      });
-      expect(parsed.success).toBe(false);
-      if (!parsed.success) {
-        const issue = parsed.error.issues.find((i) =>
-          i.path.includes("source"),
-        );
-        expect(issue, "expected a source-path rejection").toBeDefined();
-        expect(issue!.message).toMatch(/server-owned/i);
+    it("rejects every non-writable source on a client write", () => {
+      // v1.10.0 QA — the single-POST validates `source` against the
+      // client-writable subset {MANUAL, APPLE_HEALTH}. COMPUTED (server
+      // scores), WITHINGS (the Withings webhook), and IMPORT (the CSV
+      // importer) are all server-owned and must be rejected so a client
+      // cannot forge a row attributed to a source it does not own.
+      for (const source of ["COMPUTED", "WITHINGS", "IMPORT"]) {
+        const parsed = createMeasurementSchema.safeParse({
+          type: "WEIGHT",
+          value: 80,
+          measuredAt: "2026-06-02T12:00:00Z",
+          source,
+        });
+        expect(parsed.success, `expected ${source} to be rejected`).toBe(false);
+        if (!parsed.success) {
+          const issue = parsed.error.issues.find((i) =>
+            i.path.includes("source"),
+          );
+          expect(issue, `expected a source-path rejection for ${source}`).toBeDefined();
+        }
       }
     });
 
-    it("still accepts a client-writable source for a score-typed manual row", () => {
-      // The COMPUTED source is the only one this refine blocks; a MANUAL
-      // write of any type stays valid (the source guard is orthogonal to
-      // whether a UI ever offers manual score entry).
+    it("accepts the client-writable sources MANUAL and APPLE_HEALTH", () => {
+      for (const source of ["MANUAL", "APPLE_HEALTH"]) {
+        const parsed = createMeasurementSchema.safeParse({
+          type: "WEIGHT",
+          value: 80,
+          measuredAt: "2026-06-02T12:00:00Z",
+          source,
+        });
+        expect(parsed.success, `expected ${source} to be accepted`).toBe(true);
+      }
+    });
+
+    it("defaults source to MANUAL when omitted", () => {
       const parsed = createMeasurementSchema.safeParse({
-        type: "RECOVERY_SCORE",
-        value: 72,
+        type: "WEIGHT",
+        value: 80,
         measuredAt: "2026-06-02T12:00:00Z",
-        source: "MANUAL",
       });
       expect(parsed.success).toBe(true);
+      if (parsed.success) expect(parsed.data.source).toBe("MANUAL");
     });
   });
 });
diff --git a/src/lib/validations/measurement.ts b/src/lib/validations/measurement.ts
index 7c17e4ed1..48c80c76c 100644
--- a/src/lib/validations/measurement.ts
+++ b/src/lib/validations/measurement.ts
@@ -147,11 +147,24 @@ export const measurementSourceEnum = z.enum([
  */
 export const WRITABLE_MEASUREMENT_SOURCES = [
   "MANUAL",
-  "WITHINGS",
-  "IMPORT",
   "APPLE_HEALTH",
 ] as const;
 
+/**
+ * v1.10.0 QA — the Zod enum the single-entry POST validates `source` against.
+ * Built from `WRITABLE_MEASUREMENT_SOURCES` so the allowlist has one source of
+ * truth. A client may only attribute a row it actually owns: `MANUAL` (a
+ * hand-entered reading) or `APPLE_HEALTH` (the HealthKit batch's per-row
+ * source). `WITHINGS` is owned by the Withings webhook, `IMPORT` by the CSV
+ * importer, and `COMPUTED` by the nightly score engines — letting a client
+ * forge any of those would pollute the per-source canonical picker with rows
+ * the server never produced. The batch route mirrors the same exclusion with
+ * its own narrower `{APPLE_HEALTH, MANUAL}` `batchSourceEnum`.
+ */
+export const writableMeasurementSourceEnum = z.enum(
+  WRITABLE_MEASUREMENT_SOURCES,
+);
+
 const unitMap: Record<string, string> = {
   WEIGHT: "kg",
   BLOOD_PRESSURE_SYS: "mmHg",
@@ -428,7 +441,11 @@ export const createMeasurementSchema = z
     value: z.number(),
     measuredAt: z.iso.datetime({ offset: true }).transform((s) => new Date(s)),
     notes: z.string().max(MEASUREMENT_NOTES_MAX_LENGTH).optional(),
-    source: measurementSourceEnum.optional().default("MANUAL"),
+    // v1.10.0 QA — validate against the client-writable subset, not the full
+    // `MeasurementSource` enum. A client may attribute only `MANUAL` or
+    // `APPLE_HEALTH`; `WITHINGS` / `IMPORT` / `COMPUTED` are server-owned and
+    // forging them would pollute the per-source canonical picker.
+    source: writableMeasurementSourceEnum.optional().default("MANUAL"),
     // Only applies when type === BLOOD_GLUCOSE. Mirrored by a CHECK
     // constraint in Postgres (see migration 0021).
     glucoseContext: glucoseContextEnum.optional(),
@@ -453,16 +470,7 @@ export const createMeasurementSchema = z
         "Blood glucose measurements require a context (fasting/postprandial/random/bedtime); other types must not set one.",
       path: ["glucoseContext"],
     },
-  )
-  // v1.10.0 — computed scores (WX-C). The `COMPUTED` source is server-owned:
-  // a nightly engine mints those rows, a client never does. Reject it here
-  // so the single-entry POST cannot forge a server-derived row (the batch
-  // route enforces the same exclusion through its `{APPLE_HEALTH, MANUAL}`
-  // allowlist).
-  .refine((data) => data.source !== "COMPUTED", {
-    message: "The COMPUTED source is server-owned and cannot be set by a client.",
-    path: ["source"],
-  });
+  );
 
 export const updateMeasurementSchema = z.object({
   value: z.number().min(0).max(500000).optional(),