diff --git a/src/__tests__/backup-plan-classification.test.ts b/src/__tests__/backup-plan-classification.test.ts
index 393292ad3..f02ba8651 100644
--- a/src/__tests__/backup-plan-classification.test.ts
+++ b/src/__tests__/backup-plan-classification.test.ts
@@ -14,15 +14,26 @@ import {
 /**
  * Every model in the schema has a written verdict about the backup.
  *
- * This is the first half of the backup guard: classification. The second half
- * — that every `BACKED_UP` model actually has a payload reader AND a restore
- * branch — DOES NOT EXIST YET. It is the harder half and the one that matters,
- * because a model classified as carried and then never restored is the defect
- * rather than the fix, and this test would pass either way.
+ * This is the first of three checks on that claim, and the weakest one on
+ * purpose — it asks only whether a decision was written down.
  *
- * Until it lands, `BACKED_UP` means "must be carried", not "is carried".
+ *   1. here — every user-scoped model has a verdict, and every verdict names a
+ *      model the schema still has.
+ *   2. below — every model claimed two-ended has a payload reader and a restore
+ *      branch in the declared files. Source text, so it sees code that was
+ *      never written and not code that never runs.
+ *   3. `tests/integration/backup-round-trip.test.ts` — a seeded row of every
+ *      two-ended model exported, the account emptied, the restore run, the row
+ *      counted back. The only one of the three that can tell a restore branch
+ *      that runs from one that merely exists.
  *
- * The failure this prevents: a model is added to `schema.prisma`, it is
+ * An earlier version of this comment said the second half did not exist and
+ * that `BACKED_UP` therefore meant "must be carried" rather than "is carried".
+ * Both halves exist now; the sentence is rewritten rather than deleted because
+ * the sequence is the point — the classification was written first and was
+ * mistaken for proof for several releases.
+ *
+ * The failure all three prevent: a model is added to `schema.prisma`, it is
  * user-scoped from birth, and it is outside the backup by default. Nothing
  * notices, and the gap is only discovered by someone restoring a backup and
  * finding a part of their record missing — which is the worst possible moment
@@ -153,15 +164,38 @@ describe("every schema model has a backup verdict", () => {
  * retracted; `restoreCycleData` and `restoreProfileData` both live elsewhere.
  * Following the helpers is the entire difficulty of this question, so the file
  * list is declared next to the verdicts and checked to exist.
+ *
+ * ── What reading source text cannot answer ──────────────────────────────────
+ *
+ * A branch that exists and never runs. Wrapping the nutrient restore in
+ * `if (false && …)` leaves every check in this file green, because the call is
+ * still written where the matcher looks. Same for a restore that writes into
+ * the wrong account, or a transaction that rolls back. The round-trip test
+ * named above is what answers those, and the reason it is worth its runtime.
+ *
+ * A model the matcher cannot tell apart from another is named in
+ * {@link STRUCTURALLY_UNATTRIBUTABLE} with what defeats it, and is checked here
+ * only for being covered by the round trip.
  */
 
 import {
   BACKUP_RESTORE_FILES,
   BACKUP_WRITER_FILES,
   COVERAGE_PENDING,
+  STRUCTURALLY_UNATTRIBUTABLE,
   TWO_ENDED_MODELS,
 } from "@/lib/export/backup-plan";
 
+/**
+ * The behavioural half, checked from here only for its coverage.
+ *
+ * It seeds a row per two-ended model, exports through the real builder, empties
+ * the account and restores through the real route, so it is the only check that
+ * can tell a restore branch that RUNS from one that merely exists — this file
+ * stayed green with the nutrient restore wrapped in `if (false)`.
+ */
+const ROUND_TRIP_TEST = "tests/integration/backup-round-trip.test.ts";
+
 const REPO_ROOT = resolve(__dirname, "../..");
 
 function read(relativePath: string): string {
@@ -174,22 +208,39 @@ function delegateName(model: string): string {
 }
 
 /**
- * Relation fields on OTHER models whose type is `model`.
+ * Relation fields on OTHER models whose type is `model`, each with the model
+ * that declares it.
  *
  * A child rides its parent — `include: { schedules: true }` on the way out,
  * `schedules: { create: [...] }` on the way back — so a delegate-only search
  * would report every nested child as uncarried and the guard would be noise.
+ *
+ * The declaring parent comes back with the field name because a field name on
+ * its own is not evidence about a model. `symptomLinks` is declared twice —
+ * once on `IllnessDayLog` for `IllnessSymptomLink`, once on `CycleDayLog` for
+ * `CycleSymptomLink` — and a search for the bare name found the cycle write in
+ * `src/lib/cycle/backup.ts` and reported the ILLNESS link covered. Verified by
+ * deleting the illness `symptomLinks: { create: … }` branch from the restore
+ * route outright: the guard stayed green on all twelve checks, because the
+ * cycle file was answering a question about a different table.
  */
-function relationFieldNames(model: string): string[] {
+function relationParents(model: string): Array<{
+  field: string;
+  parent: string;
+}> {
   const source = readFileSync(SCHEMA_PATH, "utf8");
-  const names = new Set<string>();
-  for (const [, body] of source.matchAll(/^model\s+\w+\s*\{([\s\S]*?)^\}/gm)) {
+  const found: Array<{ field: string; parent: string }> = [];
+  for (const [, parent, body] of source.matchAll(
+    /^model\s+(\w+)\s*\{([\s\S]*?)^\}/gm,
+  )) {
     for (const line of body.split("\n")) {
       const match = /^\s*(\w+)\s+(\w+)(\[\])?\??\s*(@|$)/.exec(line);
-      if (match && match[2] === model) names.add(match[1]);
+      if (match && match[2] === model) {
+        found.push({ field: match[1], parent });
+      }
     }
   }
-  return [...names];
+  return found;
 }
 
 const READ_OPS = /(findMany|findUnique|findFirst|findUniqueOrThrow|groupBy)/;
@@ -197,28 +248,63 @@ const WRITE_OPS = /(create|createMany|upsert|update|updateMany)/;
 const READ_RELATION_OPS = /[{[t]/;
 const WRITE_RELATION_OPS = /\{\s*create\b/;
 
-/** Does any of `files` touch `model` through matching delegate and relation operations? */
+/** Does `source` call a matching operation on `model`'s own Prisma delegate? */
+function callsDelegate(source: string, model: string, ops: RegExp): boolean {
+  const delegate = delegateName(model);
+  for (const match of source.matchAll(
+    new RegExp(`\\.${delegate}\\s*\\.\\s*(\\w+)`, "g"),
+  )) {
+    if (ops.test(match[1])) return true;
+  }
+  return false;
+}
+
+/** Every model a relation field of this name points at, across the schema. */
+function targetsOfRelationField(field: string): Set<string> {
+  const source = readFileSync(SCHEMA_PATH, "utf8");
+  const targets = new Set<string>();
+  for (const [, body] of source.matchAll(/^model\s+\w+\s*\{([\s\S]*?)^\}/gm)) {
+    for (const line of body.split("\n")) {
+      const match = /^\s*(\w+)\s+(\w+)(\[\])?\??\s*(@|$)/.exec(line);
+      if (match && match[1] === field) targets.add(match[2]);
+    }
+  }
+  return targets;
+}
+
+/**
+ * Does any of `files` touch `model` through matching delegate and relation
+ * operations?
+ *
+ * A relation field name that points at exactly ONE model anywhere in the schema
+ * is evidence wherever it appears in the declared files — `schedules` can only
+ * mean `MedicationSchedule`.
+ *
+ * A name that points at SEVERAL models is evidence only in a file that also
+ * operates on the declaring parent's delegate, because otherwise the two
+ * writes are indistinguishable and either model answers for the other.
+ */
 function touches(
   files: readonly string[],
   model: string,
   delegateOps: RegExp,
   relationOps: RegExp,
 ): boolean {
-  const delegate = delegateName(model);
-  const relations = relationFieldNames(model);
   return files.some((file) => {
     // Whitespace-flattened so a call broken across lines still matches.
     const source = read(file).replace(/\s+/g, " ");
-    for (const match of source.matchAll(
-      new RegExp(`\\.${delegate}\\s*\\.\\s*(\\w+)`, "g"),
-    )) {
-      if (delegateOps.test(match[1])) return true;
-    }
-    return relations.some((relation) =>
-      new RegExp(`\\b${relation}\\s*:\\s*(?:${relationOps.source})`).test(
-        source,
-      ),
-    );
+    if (callsDelegate(source, model, delegateOps)) return true;
+    return relationParents(model).some(({ field, parent }) => {
+      if (
+        !new RegExp(`\\b${field}\\s*:\\s*(?:${relationOps.source})`).test(
+          source,
+        )
+      ) {
+        return false;
+      }
+      if (targetsOfRelationField(field).size === 1) return true;
+      return callsDelegate(source, parent, delegateOps);
+    });
   });
 }
 
@@ -234,6 +320,31 @@ describe("every backed-up model travels both ways, or is named as debt", () => {
     ).toBe(false);
   });
 
+  it("does not accept a relation name borrowed from another parent", () => {
+    // `src/lib/cycle/backup.ts` writes `symptomLinks: { create: … }` for
+    // `CycleDayLog`. The same field name belongs to `IllnessDayLog`, so the
+    // bare-name search read that line as proof the illness links are restored.
+    // The cycle file must answer for the cycle link and for nothing else.
+    expect(
+      touches(
+        ["src/lib/cycle/backup.ts"],
+        "CycleSymptomLink",
+        WRITE_OPS,
+        WRITE_RELATION_OPS,
+      ),
+      "the cycle file does write the cycle link — this half must stay true",
+    ).toBe(true);
+    expect(
+      touches(
+        ["src/lib/cycle/backup.ts"],
+        "IllnessSymptomLink",
+        WRITE_OPS,
+        WRITE_RELATION_OPS,
+      ),
+      "the cycle file says nothing about illness links and must not be read as if it did",
+    ).toBe(false);
+  });
+
   it("declares writer and restore files that exist", () => {
     for (const file of [...BACKUP_WRITER_FILES, ...BACKUP_RESTORE_FILES]) {
       expect(() => read(file), `${file} is declared but missing`).not.toThrow();
@@ -245,7 +356,7 @@ describe("every backed-up model travels both ways, or is named as debt", () => {
 
   it("splits BACKED_UP into exactly two-ended and pending, with no overlap", () => {
     const backedUp = new Set<string>(BACKED_UP_MODELS);
-    const twoEnded = new Set(TWO_ENDED_MODELS);
+    const twoEnded = new Set<string>(TWO_ENDED_MODELS);
     const pending = new Set(Object.keys(COVERAGE_PENDING));
 
     const both = [...twoEnded].filter((m) => pending.has(m));
@@ -273,6 +384,7 @@ describe("every backed-up model travels both ways, or is named as debt", () => {
   it("finds a payload reader for every model claimed two-ended", () => {
     const missing = TWO_ENDED_MODELS.filter(
       (model) =>
+        !(model in STRUCTURALLY_UNATTRIBUTABLE) &&
         !touches(BACKUP_WRITER_FILES, model, READ_OPS, READ_RELATION_OPS),
     );
     expect(
@@ -285,6 +397,7 @@ describe("every backed-up model travels both ways, or is named as debt", () => {
   it("finds a restore branch for every model claimed two-ended", () => {
     const missing = TWO_ENDED_MODELS.filter(
       (model) =>
+        !(model in STRUCTURALLY_UNATTRIBUTABLE) &&
         !touches(BACKUP_RESTORE_FILES, model, WRITE_OPS, WRITE_RELATION_OPS),
     );
     expect(
@@ -295,6 +408,40 @@ describe("every backed-up model travels both ways, or is named as debt", () => {
     ).toEqual([]);
   });
 
+  it("hands every unattributable model to the round trip instead", () => {
+    const names = Object.keys(STRUCTURALLY_UNATTRIBUTABLE);
+    const foreign = names.filter(
+      (m) => !(TWO_ENDED_MODELS as readonly string[]).includes(m),
+    );
+    expect(
+      foreign,
+      "only a model claimed two-ended has a claim for this check to be unable to attribute",
+    ).toEqual([]);
+
+    const thin = Object.entries(STRUCTURALLY_UNATTRIBUTABLE)
+      .filter(([, reason]) => reason.trim().length < 60)
+      .map(([model]) => model);
+    expect(
+      thin,
+      "say what defeats the matcher, or the next reader cannot tell an " +
+        "unprovable model from an unproven one",
+    ).toEqual([]);
+
+    // Naming a model here silences the two checks above, so it has to buy that
+    // silence with a seeded row in the round trip. Without this the record is
+    // a way to make any model's coverage question disappear.
+    const roundTrip = read(ROUND_TRIP_TEST);
+    const uncovered = names.filter(
+      (model) => !new RegExp(`\\b${model}\\s*:`).test(roundTrip),
+    );
+    expect(
+      uncovered,
+      `exempt from the structural check and absent from ${ROUND_TRIP_TEST} — ` +
+        "that is not a limitation being recorded, it is a model with nothing " +
+        "checking it at all",
+    ).toEqual([]);
+  });
+
   it("gives every pending model a reason that says what is lost", () => {
     const thin = Object.entries(COVERAGE_PENDING)
       .filter(([, reason]) => reason.trim().length < 60)
diff --git a/src/lib/export/backup-plan.ts b/src/lib/export/backup-plan.ts
index 837ded31d..13d9e01c9 100644
--- a/src/lib/export/backup-plan.ts
+++ b/src/lib/export/backup-plan.ts
@@ -33,6 +33,13 @@
  *                 defect this file was written to prevent, so it is recorded
  *                 rather than quietly corrected — and it is why the guard now
  *                 reads the source rather than trusting a list.
+ *
+ *                 Reading the source is still not the same as watching the data
+ *                 move: a restore branch wrapped in `if (false)` reads exactly
+ *                 like one that works. So the claim is settled end to end in
+ *                 `tests/integration/backup-round-trip.test.ts`, which seeds a
+ *                 row of every model named here, exports it, deletes the
+ *                 account and counts the row back out of the real restore.
  * `DERIVED`     — recomputable from `BACKED_UP` rows. Leaving it out keeps the
  *                 file smaller and cannot lose anything; the reason names what
  *                 recomputes it.
@@ -161,6 +168,11 @@ export const BACKUP_WRITER_FILES: readonly string[] = [
   // delegates" mistake the list exists to prevent, made while writing the list.
   "src/lib/export/paged-measurements.ts",
   "src/lib/export/records-backup.ts",
+  // The illness day-log's symptom include is a shared constant living here,
+  // not a literal in the records writer. Same "the caller delegates" shape as
+  // the measurement pager above, found the same way: by a check that stopped
+  // accepting one model's relation write as proof about another's.
+  "src/lib/illness/dto.ts",
   "src/lib/export/profile-backup.ts",
   "src/lib/export/intraday-profile-backup.ts",
   "src/lib/export/health-score-backup.ts",
@@ -187,8 +199,12 @@ export const BACKUP_RESTORE_FILES: readonly string[] = [
  * the whole point of the split — a verdict of `BACKED_UP` is an intention, and
  * an intention is what the nutrient day totals had while a restore was throwing
  * them away and reporting success.
+ *
+ * Frozen as a literal tuple so {@link TwoEndedModel} can key the round-trip
+ * test's seed registry. Adding a name here without seeding a row for it is then
+ * a compile error rather than a silently unproven claim.
  */
-export const TWO_ENDED_MODELS: readonly string[] = [
+export const TWO_ENDED_MODELS = [
   "Measurement",
   "IntradayCumulativeProfile",
   "Medication",
@@ -218,7 +234,30 @@ export const TWO_ENDED_MODELS: readonly string[] = [
   "Workout",
   "NutrientIntakeDay",
   "InboundDocument",
-];
+] as const;
+
+/** One model claimed to travel both ways. */
+export type TwoEndedModel = (typeof TWO_ENDED_MODELS)[number];
+
+/**
+ * Two-ended models whose coverage the structural check cannot ATTRIBUTE, with
+ * the reason each defeats it.
+ *
+ * Not an exemption from being carried — every model here is carried, and the
+ * round-trip test proves it by seeding a row, exporting, emptying the account
+ * and reading the row back out of the restore. It is an exemption from being
+ * proven by reading source text, and it exists so the limit is written down in
+ * one place instead of showing up as a green check that means nothing.
+ *
+ * A model earns a line here only when a same-file grep genuinely cannot tell
+ * two tables apart. The guard beside this file checks that each one is covered
+ * by the round trip, so naming a model here moves the burden of proof rather
+ * than dropping it.
+ */
+export const STRUCTURALLY_UNATTRIBUTABLE: Readonly<Record<string, string>> = {
+  IllnessSymptomLink:
+    "Read out through `dayLogSymptomInclude`, a shared include constant in `src/lib/illness/dto.ts` that names `symptomLinks` with no query beside it. `symptomLinks` is also `CycleDayLog`'s field for `CycleSymptomLink`, so the name alone cannot say which table a line is about, and the parent that would disambiguate it — `IllnessDayLog` — is reached transitively through the episode's `dayLogs` include in another file. Deleting the illness branch from the restore route left the old check green on the strength of the cycle write; the round trip is what notices now.",
+};
 
 /**
  * Backed-up models that do NOT travel yet, each with what an account loses
diff --git a/tests/integration/backup-round-trip.test.ts b/tests/integration/backup-round-trip.test.ts
new file mode 100644
index 000000000..e8058e90c
--- /dev/null
+++ b/tests/integration/backup-round-trip.test.ts
@@ -0,0 +1,481 @@
+/**
+ * Every model the plan claims travels both ways, proven by making it travel.
+ *
+ * `src/__tests__/backup-plan-classification.test.ts` reads source text. That
+ * catches a reader or a restore branch that was never written, and it is cheap
+ * enough to run on every `pnpm test` — but it cannot tell a branch that RUNS
+ * from one that merely exists. Verified rather than assumed: wrapping the
+ * nutrient restore in `if (false && …)` left all twelve of its checks green.
+ * Correct, green, and inert in production is the failure mode this repository
+ * has already shipped once, so the claim needs an end-to-end answer as well.
+ *
+ * This is that answer, and it is deliberately the LONG way round:
+ *
+ *   1. Seed one row of every model in `TWO_ENDED_MODELS` for one account.
+ *   2. Export through the real `buildFullBackupPayload`, disaster-recovery
+ *      purpose — the same builder both export routes and the weekly worker use.
+ *   3. Delete the account. Not a hand-listed `deleteMany` sweep, which can only
+ *      empty the tables somebody remembered: `user.delete()` cascades, so what
+ *      survives is exactly what the schema says survives. A model that is
+ *      neither wiped nor restored would otherwise be counted as recovered on
+ *      the strength of the row that was never removed.
+ *   4. Re-create the account under the same id and restore through the real
+ *      `POST /api/admin/backups/[id]/restore`.
+ *   5. Count each model back. Zero means the account came back short.
+ *
+ * The registry below is keyed by `TwoEndedModel`, so a name added to the plan's
+ * two-ended list without a row seeded and counted here does not compile.
+ *
+ * What this still does not prove: that a restored row carries the right VALUES.
+ * It asks whether the rows came back, not whether they came back intact —
+ * `admin-backups-canonical-roundtrip.test.ts` is where field-level fidelity is
+ * asserted. A restore that wrote one row per model with every column defaulted
+ * would satisfy this file and fail that one.
+ */
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+process.env.ENCRYPTION_KEY ??=
+  "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
+
+import type { PrismaClient } from "@/generated/prisma/client";
+import { encrypt, encryptBytes } from "@/lib/crypto";
+import { encryptToBytes } from "@/lib/ai/coach/bytes-codec";
+import { buildFullBackupPayload } from "@/lib/export/full-backup-payload";
+import { TWO_ENDED_MODELS, type TwoEndedModel } from "@/lib/export/backup-plan";
+import { POST } from "@/app/api/admin/backups/[id]/restore/route";
+
+import { cookieJar, headerJar } from "./mock-next-headers";
+import { getPrismaClient, truncateAllTables } from "./setup";
+
+vi.mock("next/headers", async () => {
+  const { cookieJar, headerJar } = await import("./mock-next-headers");
+  return {
+    headers: vi.fn(async () => ({
+      get: (name: string) => headerJar.get(name.toLowerCase()) ?? null,
+    })),
+    cookies: vi.fn(async () => ({
+      get: (name: string) => {
+        const value = cookieJar.get(name);
+        return value ? { name, value } : undefined;
+      },
+      set: (name: string, value: string) => cookieJar.set(name, value),
+      delete: (name: string) => cookieJar.delete(name),
+    })),
+  };
+});
+
+vi.mock("@/lib/db-compat", () => ({
+  ensureDbCompatibility: vi.fn().mockResolvedValue(undefined),
+}));
+
+vi.mock("@/lib/cache/invalidate", () => ({
+  invalidateUserData: vi.fn(),
+}));
+
+const OWNER_ID = "round-trip-owner";
+const AT = (iso: string) => new Date(iso);
+
+beforeEach(async () => {
+  await truncateAllTables(getPrismaClient());
+  cookieJar.clear();
+  headerJar.clear();
+});
+
+/** Counts what belongs to `userId`, following the relation where there is no own column. */
+const COUNT_BACK: Record<
+  TwoEndedModel,
+  (prisma: PrismaClient, userId: string) => Promise<number>
+> = {
+  Measurement: (p, userId) => p.measurement.count({ where: { userId } }),
+  IntradayCumulativeProfile: (p, userId) =>
+    p.intradayCumulativeProfile.count({ where: { userId } }),
+  Medication: (p, userId) => p.medication.count({ where: { userId } }),
+  MedicationSchedule: (p, userId) =>
+    p.medicationSchedule.count({ where: { medication: { userId } } }),
+  MedicationIntakeEvent: (p, userId) =>
+    p.medicationIntakeEvent.count({ where: { userId } }),
+  MoodEntry: (p, userId) => p.moodEntry.count({ where: { userId } }),
+  MoodEntryTagLink: (p, userId) =>
+    p.moodEntryTagLink.count({ where: { moodEntry: { userId } } }),
+  MoodTag: (p, userId) => p.moodTag.count({ where: { userId } }),
+  LabResult: (p, userId) => p.labResult.count({ where: { userId } }),
+  Biomarker: (p, userId) => p.biomarker.count({ where: { userId } }),
+  Allergy: (p, userId) => p.allergy.count({ where: { userId } }),
+  FamilyHistoryEntry: (p, userId) =>
+    p.familyHistoryEntry.count({ where: { userId } }),
+  IllnessEpisode: (p, userId) => p.illnessEpisode.count({ where: { userId } }),
+  IllnessDayLog: (p, userId) => p.illnessDayLog.count({ where: { userId } }),
+  IllnessSymptomLink: (p, userId) =>
+    p.illnessSymptomLink.count({ where: { dayLog: { userId } } }),
+  UserHealthProfile: (p, userId) =>
+    p.userHealthProfile.count({ where: { userId } }),
+  HealthProfileFactRevision: (p, userId) =>
+    p.healthProfileFactRevision.count({ where: { userId } }),
+  CycleProfile: (p, userId) => p.cycleProfile.count({ where: { userId } }),
+  MenstrualCycle: (p, userId) => p.menstrualCycle.count({ where: { userId } }),
+  CycleDayLog: (p, userId) => p.cycleDayLog.count({ where: { userId } }),
+  CycleSymptom: (p, userId) => p.cycleSymptom.count({ where: { userId } }),
+  CycleSymptomLink: (p, userId) =>
+    p.cycleSymptomLink.count({ where: { dayLog: { userId } } }),
+  CustomMetric: (p, userId) => p.customMetric.count({ where: { userId } }),
+  CustomMetricEntry: (p, userId) =>
+    p.customMetricEntry.count({ where: { userId } }),
+  CorrelationPattern: (p, userId) =>
+    p.correlationPattern.count({ where: { userId } }),
+  HealthScoreRecord: (p, userId) =>
+    p.healthScoreRecord.count({ where: { userId } }),
+  Workout: (p, userId) => p.workout.count({ where: { userId } }),
+  NutrientIntakeDay: (p, userId) =>
+    p.nutrientIntakeDay.count({ where: { userId } }),
+  InboundDocument: (p, userId) =>
+    p.inboundDocument.count({ where: { userId } }),
+};
+
+/**
+ * One row of every two-ended model, for one account.
+ *
+ * Minimal on purpose: this file asks whether a row survives the round trip, and
+ * a fat fixture only makes the answer slower to get. The mood factor and the
+ * cycle symptom are the account's OWN custom rows rather than seeded catalogue
+ * entries, because a catalogue row survives the account being deleted and would
+ * make the link tables look restored when nothing restored them.
+ */
+async function seedEveryTwoEndedModel(prisma: PrismaClient): Promise<void> {
+  await prisma.measurement.create({
+    data: {
+      userId: OWNER_ID,
+      type: "WEIGHT",
+      value: 74.2,
+      unit: "kg",
+      measuredAt: AT("2026-07-01T07:00:00.000Z"),
+      source: "MANUAL",
+    },
+  });
+  await prisma.intradayCumulativeProfile.create({
+    data: {
+      userId: OWNER_ID,
+      type: "ACTIVITY_STEPS",
+      dateKey: "2026-07-01",
+      // One slot per hour — the restore refuses a profile of any other length,
+      // because a short row lands in the table and is dropped on read.
+      hourlyCumulative: Array.from({ length: 24 }, (_, hour) => hour * 350),
+      dayTotal: 8050,
+      sampleCount: 24,
+      timezone: "Europe/Berlin",
+    },
+  });
+
+  const medication = await prisma.medication.create({
+    data: {
+      userId: OWNER_ID,
+      name: "Round-trip tablet",
+      dose: "5 mg",
+      schedules: {
+        create: { windowStart: "08:00", windowEnd: "09:00", label: "Morning" },
+      },
+    },
+  });
+  await prisma.medicationIntakeEvent.create({
+    data: {
+      userId: OWNER_ID,
+      medicationId: medication.id,
+      scheduledFor: AT("2026-07-01T08:00:00.000Z"),
+      takenAt: AT("2026-07-01T08:04:00.000Z"),
+    },
+  });
+
+  // A RATED tag the account defined itself — the export carries only rated
+  // links, so a BINARY tag would leave `MoodEntryTagLink` empty.
+  const moodCategory = await prisma.moodTagCategory.findFirstOrThrow({
+    where: { userId: null },
+  });
+  const moodTag = await prisma.moodTag.create({
+    data: {
+      userId: OWNER_ID,
+      categoryId: moodCategory.id,
+      key: "round_trip_factor",
+      labelKey: "mood.tag.roundTripFactor",
+      kind: "RATED",
+      scaleMin: 1,
+      scaleMax: 5,
+    },
+  });
+  await prisma.moodEntry.create({
+    data: {
+      userId: OWNER_ID,
+      date: "2026-07-01",
+      mood: "GUT",
+      score: 4,
+      source: "MOODLOG",
+      moodLoggedAt: AT("2026-07-01T20:00:00.000Z"),
+      tagLinks: { create: { moodTagId: moodTag.id, rating: 4 } },
+    },
+  });
+
+  const biomarker = await prisma.biomarker.create({
+    data: { userId: OWNER_ID, name: "Ferritin", unit: "ng/mL" },
+  });
+  await prisma.labResult.create({
+    data: {
+      userId: OWNER_ID,
+      biomarkerId: biomarker.id,
+      analyte: "Ferritin",
+      value: 91,
+      unit: "ng/mL",
+      takenAt: AT("2026-06-30T09:00:00.000Z"),
+    },
+  });
+  await prisma.allergy.create({
+    data: { userId: OWNER_ID, substance: "Penicillin" },
+  });
+  await prisma.familyHistoryEntry.create({
+    data: {
+      userId: OWNER_ID,
+      relationship: "MOTHER",
+      condition: "Type 2 diabetes",
+    },
+  });
+
+  const episode = await prisma.illnessEpisode.create({
+    data: {
+      userId: OWNER_ID,
+      label: "Cold",
+      type: "INFECTION",
+      onsetAt: AT("2026-06-20T00:00:00.000Z"),
+    },
+  });
+  const illnessSymptom = await prisma.illnessSymptom.create({
+    data: { key: "round_trip_cough", labelKey: "illness.symptom.roundTrip" },
+  });
+  await prisma.illnessDayLog.create({
+    data: {
+      userId: OWNER_ID,
+      episodeId: episode.id,
+      date: "2026-06-21",
+      symptomLinks: { create: { symptomId: illnessSymptom.id, severity: 2 } },
+    },
+  });
+
+  await prisma.userHealthProfile.create({
+    data: {
+      userId: OWNER_ID,
+      aboutMeEncrypted: encryptToBytes("Runs three times a week"),
+    },
+  });
+  await prisma.healthProfileFactRevision.create({
+    data: {
+      userId: OWNER_ID,
+      kind: "SMOKING_STATUS",
+      valueEncrypted: encryptToBytes("never"),
+      validFrom: AT("2026-01-01T00:00:00.000Z"),
+    },
+  });
+
+  await prisma.cycleProfile.create({
+    data: { userId: OWNER_ID, cycleTrackingEnabled: true },
+  });
+  const cycle = await prisma.menstrualCycle.create({
+    data: { userId: OWNER_ID, startDate: "2026-06-01" },
+  });
+  const cycleCategory = await prisma.cycleSymptomCategory.findFirstOrThrow();
+  const cycleSymptom = await prisma.cycleSymptom.create({
+    data: {
+      userId: OWNER_ID,
+      categoryId: cycleCategory.id,
+      key: "custom:round-trip-cramps",
+      labelKey: "cycle.symptom.custom",
+      labelEncrypted: encrypt("Round-trip cramps"),
+    },
+  });
+  await prisma.cycleDayLog.create({
+    data: {
+      userId: OWNER_ID,
+      cycleId: cycle.id,
+      date: "2026-06-02",
+      flow: "HEAVY",
+      symptomLinks: { create: { symptomId: cycleSymptom.id } },
+    },
+  });
+
+  await prisma.customMetric.create({
+    data: {
+      userId: OWNER_ID,
+      name: "Grip strength",
+      unit: "kg",
+      entries: {
+        create: {
+          userId: OWNER_ID,
+          value: 44,
+          unit: "kg",
+          measuredAt: AT("2026-07-01T18:00:00.000Z"),
+        },
+      },
+    },
+  });
+  await prisma.correlationPattern.create({
+    data: {
+      userId: OWNER_ID,
+      canonicalKey: `p1:${"a1".repeat(32)}`,
+      family: "sleep",
+      factorKey: "sleep_duration",
+      outcomeKey: "weight",
+      lagDays: 1,
+      sampleSize: 30,
+      effectSize: 0.42,
+      pValue: 0.01,
+      evidenceHash: "b2".repeat(32),
+      lastComputedAt: AT("2026-07-01T00:00:00.000Z"),
+    },
+  });
+  await prisma.healthScoreRecord.create({
+    data: {
+      userId: OWNER_ID,
+      dayKey: "2026-07-01",
+      timezone: "Europe/Berlin",
+      composite: 71,
+      band: "green",
+      scoreVersion: 1,
+      composition: ["activity", "sleep"],
+      pillarScores: { activity: 70, sleep: 72 },
+      inputFingerprint: "c3".repeat(32),
+    },
+  });
+
+  await prisma.workout.create({
+    data: {
+      userId: OWNER_ID,
+      sportType: "RUNNING",
+      startedAt: AT("2026-06-29T06:00:00.000Z"),
+      endedAt: AT("2026-06-29T06:30:00.000Z"),
+      durationSec: 1800,
+    },
+  });
+  await prisma.nutrientIntakeDay.create({
+    data: {
+      userId: OWNER_ID,
+      day: "2026-07-01",
+      nutrient: "WATER",
+      amount: 2100,
+      unit: "ml",
+      source: "MANUAL",
+    },
+  });
+
+  const documentBytes = encryptBytes(Buffer.from("round-trip document bytes"));
+  const contentEncrypted = new Uint8Array(
+    new ArrayBuffer(documentBytes.byteLength),
+  );
+  contentEncrypted.set(documentBytes);
+  await prisma.inboundDocument.create({
+    data: {
+      userId: OWNER_ID,
+      kind: "LAB_RESULT",
+      title: "June labs",
+      filename: "june-labs.pdf",
+      mimeType: "application/pdf",
+      byteSize: documentBytes.byteLength,
+      contentEncrypted,
+      contentCodec: "binary2",
+    },
+  });
+}
+
+async function createOwner(prisma: PrismaClient) {
+  return prisma.user.create({
+    data: {
+      id: OWNER_ID,
+      username: "round-trip-owner",
+      email: "round-trip-owner@example.test",
+    },
+  });
+}
+
+async function seedAdminSession(prisma: PrismaClient) {
+  const admin = await prisma.user.create({
+    data: {
+      username: "round-trip-admin",
+      email: "round-trip-admin@example.test",
+      role: "ADMIN",
+    },
+  });
+  const session = await prisma.session.create({
+    data: { userId: admin.id, expiresAt: new Date(Date.now() + 60_000) },
+  });
+  cookieJar.set("healthlog_session", session.id);
+  return admin;
+}
+
+describe("every model the plan claims two-ended survives a real restore", () => {
+  it("carries a seeded row of each model out of the account and back in", async () => {
+    const prisma = getPrismaClient();
+    await seedAdminSession(prisma);
+    await createOwner(prisma);
+    await seedEveryTwoEndedModel(prisma);
+
+    // The fixture has to be complete before the account is deleted, or a model
+    // seeded with zero rows would come back with zero and read as restored.
+    const seeded = await Promise.all(
+      TWO_ENDED_MODELS.map(async (model) => [
+        model,
+        await COUNT_BACK[model](prisma, OWNER_ID),
+      ]),
+    );
+    expect(
+      seeded.filter(([, count]) => count === 0).map(([model]) => model),
+      "seeded no row for these, so the assertion after the restore would " +
+        "compare nothing against nothing and pass",
+    ).toEqual([]);
+
+    const { payload } = await buildFullBackupPayload(prisma, OWNER_ID, {
+      purpose: "disaster-recovery",
+    });
+
+    // Cascade rather than a hand-listed sweep — see the file comment.
+    await prisma.user.delete({ where: { id: OWNER_ID } });
+    await createOwner(prisma);
+    const emptied = await Promise.all(
+      TWO_ENDED_MODELS.map((model) => COUNT_BACK[model](prisma, OWNER_ID)),
+    );
+    expect(
+      emptied.reduce((total, count) => total + count, 0),
+      "the account still owns rows after being deleted, so the restore is " +
+        "not what put them there",
+    ).toBe(0);
+
+    const backup = await prisma.dataBackup.create({
+      data: {
+        userId: OWNER_ID,
+        type: "TWO_ENDED_ROUND_TRIP",
+        data: encrypt(JSON.stringify(payload)),
+      },
+    });
+    const response = await POST(
+      new Request(`http://localhost/api/admin/backups/${backup.id}/restore`, {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ confirm: "RESTORE" }),
+      }) as never,
+      { params: Promise.resolve({ id: backup.id }) },
+    );
+    const body = await response.json();
+    expect(response.status, JSON.stringify(body)).toBe(200);
+    expect(
+      body.data.skipped.links,
+      "a dropped link is a row that did not " +
+        "come back, reported rather than silent",
+    ).toBe(0);
+
+    const restored = await Promise.all(
+      TWO_ENDED_MODELS.map(async (model) => [
+        model,
+        await COUNT_BACK[model](prisma, OWNER_ID),
+      ]),
+    );
+    expect(
+      restored.filter(([, count]) => count === 0).map(([model]) => model),
+      "the plan claims these travel both ways; the account was restored " +
+        "without them, which is a backup that reports success and hands back " +
+        "less than it was given",
+    ).toEqual([]);
+  });
+});