diff --git a/docs/ops/intake-repair.md b/docs/ops/intake-repair.md
new file mode 100644
index 000000000..c7c9e7099
--- /dev/null
+++ b/docs/ops/intake-repair.md
@@ -0,0 +1,79 @@
+# Medication intake repair
+
+`scripts/repair-intake-anomalies.ts` repairs two known historic defects in
+the medication intake ledger (`medication_intake_events`):
+
+1. **Duplicate dose-slot rows.** More than one live row on the same exact
+   `(user, medication, scheduled_for)` tuple — cross-source duplicates the
+   pre-v1.15.19 write path could mint (e.g. a pending REMINDER row plus a
+   taken API row for the same slot). The duplicate inflates the per-day
+   scheduled count and paints a phantom entry in the history view.
+2. **Implausible `taken_at`.** Live rows whose `taken_at` lands more than
+   7 days before `scheduled_for` or more than 1 day in the future —
+   typically the residue of a mis-attributed edit before the v1.15.19
+   `taken_at` validation landed.
+
+## When to use it
+
+- After upgrading to v1.15.19+, when a user reports a compliance rate above
+  100 %, duplicate entries in the medication history, or a dose shown as
+  taken days away from its slot.
+- The compliance rollup counts DISTINCT slots since v1.15.19, so the
+  percentages self-correct on recompute even without running this script.
+  Running it additionally clears the phantom rows from the history view.
+- The `intake-slot-dedup` worker already collapses canonical-slot
+  duplicates at boot and on a daily cron; this script is the manual,
+  immediately-observable fallback and the only path that surfaces the
+  implausible-`taken_at` rows.
+
+## Run a dry-run first
+
+Always. The default mode only reports and never mutates:
+
+```bash
+# inside the app container (or any checkout with DATABASE_URL set)
+pnpm dlx tsx scripts/repair-intake-anomalies.ts
+
+# scoped to one account
+pnpm dlx tsx scripts/repair-intake-anomalies.ts --user <userId>
+```
+
+Use `pnpm dlx tsx`, not bare `pnpm tsx` — the production standalone image
+strips `tsx`. `DATABASE_URL` must point at the target database.
+
+The dry-run prints every duplicate group (which row would be kept, which
+would be tombstoned) and a table of implausible rows (id, medication,
+`scheduledFor`, `takenAt`, source, timestamps).
+
+## Applying the fix
+
+```bash
+pnpm dlx tsx scripts/repair-intake-anomalies.ts --fix
+```
+
+`--fix` does three things:
+
+- **Duplicate groups** are collapsed to one winner per slot. Precedence:
+  an actioned row (taken or skipped) beats a pending one; between two
+  taken rows the earlier `taken_at` wins; ties break deterministically on
+  `created_at`, then `id`. Losers are soft-deleted (`deleted_at` set,
+  `sync_version` incremented) — the same tombstone shape the delete route
+  writes, so connected clients drop the rows on their next delta-sync.
+  Nothing is ever hard-deleted.
+- **Implausible `taken_at` rows are NOT touched.** The recorded intent is
+  unknowable, so the operator (or the user) corrects or deletes them in
+  the medication history tab. To soft-delete them wholesale instead, opt
+  in explicitly:
+
+  ```bash
+  pnpm dlx tsx scripts/repair-intake-anomalies.ts --fix --tombstone-implausible
+  ```
+
+  `--tombstone-implausible` is refused without `--fix`.
+- **Affected compliance rollups are recomputed** for every touched
+  `(user, medication, day)` through the shared rollup helper, so the
+  scheduled/taken counts and the rate self-correct immediately.
+
+The script is idempotent: a second `--fix` run finds zero duplicate groups
+and changes nothing. Exit code is 0 on success (including a clean
+zero-findings run), non-zero on bad arguments or a fatal error.
diff --git a/scripts/README.md b/scripts/README.md
index 5fcadab54..7834722dc 100644
--- a/scripts/README.md
+++ b/scripts/README.md
@@ -18,6 +18,7 @@ Use `pnpm dlx tsx`, not bare `pnpm tsx`. The production standalone image strips
 - **`assert-deploy.ts`** — post-deploy `/api/version` assertion.
 - **`rotate-encryption-key.ts`** — AES-256-GCM key rotation; see `docs/ops/encryption-key-rotation.md`.
 - **`restore-backup.ts`** — restore an off-host AES-GCM backup from an S3-compatible bucket.
+- **`repair-intake-anomalies.ts`** — repair historic medication-ledger defects (duplicate dose-slot rows, implausible `taken_at`); dry-run by default, see `docs/ops/intake-repair.md`.
 - **`backfill-rollups.ts`**, **`drain-per-sample-cumulative.ts`**, **`backfill-mood-note-column.ts`** — historical data backfills (note: the boot-time `rollup-full-backfill` queue handles new accounts automatically; the CLI is the manual fallback).
 - **`seed-demo.ts`** + **`seed-demo-v15.sql`** — populate a demo tenant.
 - **`test-notifications.ts`** — exercise the notification dispatcher + reminder check.
diff --git a/scripts/repair-intake-anomalies.ts b/scripts/repair-intake-anomalies.ts
new file mode 100644
index 000000000..47efeadb7
--- /dev/null
+++ b/scripts/repair-intake-anomalies.ts
@@ -0,0 +1,381 @@
+/**
+ * scripts/repair-intake-anomalies.ts — operator repair for the two known
+ * historic medication-ledger defects:
+ *
+ *   1. SLOT DUPLICATES — more than one live `medication_intake_events` row
+ *      on the same exact `(user_id, medication_id, scheduled_for)` tuple
+ *      (cross-source duplicates the pre-v1.15.19 write path could mint).
+ *      Repair: keep one winner per slot (H1 precedence, see `pickWinner`
+ *      below) and soft-delete the losers — `deleted_at = now()`,
+ *      `sync_version` incremented, `updated_at` bumped via `@updatedAt` —
+ *      exactly the tombstone shape the per-event DELETE route and the
+ *      `intake-slot-dedup` worker write, so iOS delta-sync drops them.
+ *
+ *   2. IMPLAUSIBLE TAKEN_AT — live rows whose `taken_at` lands more than
+ *      7 days before `scheduled_for` or more than 1 day in the future.
+ *      User intention is unknowable here, so these are REPORTED only
+ *      (correct or delete them in the medication history tab). With
+ *      `--fix --tombstone-implausible` the operator can explicitly opt
+ *      into soft-deleting them.
+ *
+ * After any mutation the affected `(user, medication, day)` compliance
+ * rollups are recomputed through the shared rollup helpers — no SQL is
+ * duplicated here. The rollup aggregates DISTINCT slots since v1.15.19,
+ * so a recompute alone already heals the counts; the tombstones
+ * additionally clear the phantom rows from the history view.
+ *
+ * Default is a DRY-RUN that only reports. Idempotent: a second `--fix`
+ * run finds zero groups and changes nothing.
+ *
+ * Usage
+ * -----
+ *   pnpm dlx tsx scripts/repair-intake-anomalies.ts                  # dry-run
+ *   pnpm dlx tsx scripts/repair-intake-anomalies.ts --user <id>      # scoped dry-run
+ *   pnpm dlx tsx scripts/repair-intake-anomalies.ts --fix
+ *   pnpm dlx tsx scripts/repair-intake-anomalies.ts --fix --tombstone-implausible
+ *
+ * `DATABASE_URL` must point at the target database.
+ */
+import "dotenv/config";
+import { Prisma } from "@/generated/prisma/client";
+import { prisma } from "@/lib/db";
+import {
+  dayKeyForScheduledFor,
+  recomputeMedicationComplianceForDay,
+} from "@/lib/rollups/medication-compliance-rollups";
+
+const TAG = "[repair-intake-anomalies]";
+
+interface CliOptions {
+  fix: boolean;
+  tombstoneImplausible: boolean;
+  userId: string | null;
+}
+
+function parseArgs(argv: string[]): CliOptions {
+  const opts: CliOptions = {
+    fix: false,
+    tombstoneImplausible: false,
+    userId: null,
+  };
+  for (let i = 0; i < argv.length; i++) {
+    const arg = argv[i];
+    if (arg === "--fix") {
+      opts.fix = true;
+    } else if (arg === "--tombstone-implausible") {
+      opts.tombstoneImplausible = true;
+    } else if (arg === "--user" && argv[i + 1]) {
+      opts.userId = argv[i + 1];
+      i += 1;
+    } else {
+      console.error(`${TAG} unknown argument: ${arg}`);
+      process.exit(2);
+    }
+  }
+  return opts;
+}
+
+interface IntakeRow {
+  id: string;
+  takenAt: Date | null;
+  skipped: boolean;
+  source: string;
+  createdAt: Date;
+}
+
+/**
+ * Rank a row for the slot-winner pick: taken (2) > skipped (1) >
+ * pending (0). `takenAt` set and `skipped` together still counts as
+ * taken — the recorded dose dominates.
+ */
+function rowRank(row: IntakeRow): number {
+  if (row.takenAt !== null) return 2;
+  if (row.skipped) return 1;
+  return 0;
+}
+
+/**
+ * Pick the winner among the live rows sharing one exact slot.
+ *
+ * H1 precedence — neither in-tree helper is exported, so the rule is
+ * rebuilt here; see `pickSlotRow` in
+ * `src/lib/medications/scheduling/slot-upsert.ts` (actioned > pending,
+ * deterministic `createdAt asc, id asc` tie-break) and `pickWinner` in
+ * `src/lib/medications/intake-slot-dedup.ts` (taken > skipped > pending):
+ *
+ *   1. actioned beats pending (never resurrect a phantom pending row;
+ *      deleting a recorded dose would under-report adherence — the
+ *      dangerous direction);
+ *   2. between two taken rows the EARLIER `takenAt` wins — the first
+ *      recorded intake is the dose of record;
+ *   3. final tie-break `createdAt asc`, then `id asc` — fully
+ *      deterministic across runs and DB orderings.
+ */
+function pickWinner(rows: IntakeRow[]): IntakeRow {
+  return [...rows].sort((a, b) => {
+    const rank = rowRank(b) - rowRank(a);
+    if (rank !== 0) return rank;
+    if (a.takenAt !== null && b.takenAt !== null) {
+      const dt = a.takenAt.getTime() - b.takenAt.getTime();
+      if (dt !== 0) return dt;
+    }
+    const created = a.createdAt.getTime() - b.createdAt.getTime();
+    if (created !== 0) return created;
+    return a.id < b.id ? -1 : 1;
+  })[0];
+}
+
+/** `userId -> timezone` cache for the rollup day-key derivation. */
+const tzCache = new Map<string, string | null>();
+
+async function userTimezone(userId: string): Promise<string | null> {
+  if (!tzCache.has(userId)) {
+    const user = await prisma.user.findUnique({
+      where: { id: userId },
+      select: { timezone: true },
+    });
+    tzCache.set(userId, user?.timezone ?? null);
+  }
+  return tzCache.get(userId) ?? null;
+}
+
+interface Summary {
+  duplicateGroups: number;
+  rowsTombstoned: number;
+  implausibleRows: number;
+  implausibleTombstoned: number;
+  rollupsRecomputed: number;
+}
+
+async function main(): Promise<void> {
+  if (!process.env.DATABASE_URL) {
+    console.error(`${TAG} DATABASE_URL must be set`);
+    process.exit(1);
+  }
+
+  const opts = parseArgs(process.argv.slice(2));
+  if (opts.tombstoneImplausible && !opts.fix) {
+    console.error(
+      `${TAG} --tombstone-implausible requires --fix (dry-run never mutates)`,
+    );
+    process.exit(2);
+  }
+
+  console.log(
+    `${TAG} mode=${opts.fix ? "FIX" : "DRY-RUN"}` +
+      (opts.tombstoneImplausible ? " +tombstone-implausible" : "") +
+      (opts.userId ? ` user=${opts.userId}` : " (all users)"),
+  );
+
+  const summary: Summary = {
+    duplicateGroups: 0,
+    rowsTombstoned: 0,
+    implausibleRows: 0,
+    implausibleTombstoned: 0,
+    rollupsRecomputed: 0,
+  };
+
+  const userFilter = opts.userId
+    ? Prisma.sql`AND e."user_id" = ${opts.userId}`
+    : Prisma.empty;
+
+  // `(userId, medicationId, dayKey)` tuples whose compliance rollup needs
+  // a recompute after the tombstones. Deduped so a busy day folds once.
+  const daysToRecompute = new Set<string>();
+
+  // ───────────────────────────────────────────────────────────────────
+  // 1. Slot duplicates — exact (user, medication, scheduled_for) tuples
+  //    carrying more than one live row.
+  // ───────────────────────────────────────────────────────────────────
+  const groups = await prisma.$queryRaw<
+    Array<{
+      user_id: string;
+      medication_id: string;
+      scheduled_for: Date;
+      row_count: number;
+    }>
+  >`
+    SELECT e."user_id", e."medication_id", e."scheduled_for",
+           COUNT(*)::int AS row_count
+    FROM "medication_intake_events" e
+    WHERE e."deleted_at" IS NULL
+      ${userFilter}
+    GROUP BY e."user_id", e."medication_id", e."scheduled_for"
+    HAVING COUNT(*) > 1
+    ORDER BY e."user_id", e."medication_id", e."scheduled_for"
+  `;
+
+  summary.duplicateGroups = groups.length;
+  console.log(`\n${TAG} 1) duplicate slot groups found: ${groups.length}`);
+
+  for (const group of groups) {
+    const rows = (await prisma.medicationIntakeEvent.findMany({
+      where: {
+        userId: group.user_id,
+        medicationId: group.medication_id,
+        scheduledFor: group.scheduled_for,
+        deletedAt: null,
+      },
+      select: {
+        id: true,
+        takenAt: true,
+        skipped: true,
+        source: true,
+        createdAt: true,
+      },
+      orderBy: [{ createdAt: "asc" }, { id: "asc" }],
+    })) as IntakeRow[];
+    if (rows.length < 2) continue; // collapsed since the scan — nothing to do.
+
+    const winner = pickWinner(rows);
+    const losers = rows.filter((r) => r.id !== winner.id);
+
+    console.log(
+      `  - user=${group.user_id} medication=${group.medication_id} ` +
+        `slot=${group.scheduled_for.toISOString()} rows=${rows.length} ` +
+        `keep=${winner.id} (${winner.source}, ` +
+        `${winner.takenAt ? `taken ${winner.takenAt.toISOString()}` : winner.skipped ? "skipped" : "pending"}) ` +
+        `tombstone=[${losers.map((r) => `${r.id} (${r.source})`).join(", ")}]`,
+    );
+
+    if (opts.fix) {
+      // Same tombstone the per-event DELETE route and the dedup worker
+      // write: soft-delete + syncVersion bump (the sync feed echoes a
+      // monotonic value so iOS drops the row); `updatedAt` bumps via the
+      // schema's `@updatedAt`. The `deletedAt: null` guard keeps the
+      // write idempotent against a concurrent collapse.
+      const res = await prisma.medicationIntakeEvent.updateMany({
+        where: { id: { in: losers.map((r) => r.id) }, deletedAt: null },
+        data: { deletedAt: new Date(), syncVersion: { increment: 1 } },
+      });
+      summary.rowsTombstoned += res.count;
+
+      const tz = await userTimezone(group.user_id);
+      const dayKey = dayKeyForScheduledFor(group.scheduled_for, tz);
+      daysToRecompute.add(
+        `${group.user_id}|${group.medication_id}|${dayKey}`,
+      );
+    }
+  }
+
+  // ───────────────────────────────────────────────────────────────────
+  // 2. Implausible taken_at — report only; tombstone needs explicit
+  //    operator opt-in.
+  // ───────────────────────────────────────────────────────────────────
+  const implausible = await prisma.$queryRaw<
+    Array<{
+      id: string;
+      user_id: string;
+      medication_id: string;
+      medication_name: string;
+      scheduled_for: Date;
+      taken_at: Date;
+      source: string;
+      created_at: Date;
+      updated_at: Date;
+    }>
+  >`
+    SELECT e."id", e."user_id", e."medication_id",
+           m."name" AS medication_name,
+           e."scheduled_for", e."taken_at", e."source"::text AS source,
+           e."created_at", e."updated_at"
+    FROM "medication_intake_events" e
+    JOIN "medications" m ON m."id" = e."medication_id"
+    WHERE e."deleted_at" IS NULL
+      AND e."taken_at" IS NOT NULL
+      AND (e."taken_at" < e."scheduled_for" - interval '7 days'
+           OR e."taken_at" > now() + interval '1 day')
+      ${userFilter}
+    ORDER BY e."user_id", e."taken_at"
+  `;
+
+  summary.implausibleRows = implausible.length;
+  console.log(`\n${TAG} 2) implausible taken_at rows found: ${implausible.length}`);
+  if (implausible.length > 0) {
+    console.table(
+      implausible.map((r) => ({
+        id: r.id,
+        medication: r.medication_name,
+        scheduledFor: r.scheduled_for.toISOString(),
+        takenAt: r.taken_at.toISOString(),
+        source: r.source,
+        createdAt: r.created_at.toISOString(),
+        updatedAt: r.updated_at.toISOString(),
+      })),
+    );
+    if (!(opts.fix && opts.tombstoneImplausible)) {
+      console.log(
+        `${TAG} these rows are NOT changed automatically — the recorded ` +
+          `intent is unknowable. Correct or delete them in the medication ` +
+          `history tab, or re-run with --fix --tombstone-implausible to ` +
+          `soft-delete them.`,
+      );
+    }
+  }
+
+  if (opts.fix && opts.tombstoneImplausible && implausible.length > 0) {
+    const res = await prisma.medicationIntakeEvent.updateMany({
+      where: {
+        id: { in: implausible.map((r) => r.id) },
+        deletedAt: null,
+      },
+      data: { deletedAt: new Date(), syncVersion: { increment: 1 } },
+    });
+    summary.implausibleTombstoned = res.count;
+    console.log(
+      `${TAG} tombstoned ${res.count} implausible row(s) (operator opt-in)`,
+    );
+
+    for (const row of implausible) {
+      const tz = await userTimezone(row.user_id);
+      const dayKey = dayKeyForScheduledFor(row.scheduled_for, tz);
+      daysToRecompute.add(`${row.user_id}|${row.medication_id}|${dayKey}`);
+    }
+  }
+
+  // ───────────────────────────────────────────────────────────────────
+  // 3. Recompute the affected compliance rollups so scheduled/taken
+  //    counts self-correct. Shared helper — no SQL duplicated here.
+  // ───────────────────────────────────────────────────────────────────
+  if (opts.fix && daysToRecompute.size > 0) {
+    console.log(
+      `\n${TAG} 3) recomputing ${daysToRecompute.size} compliance rollup day(s)`,
+    );
+    for (const key of daysToRecompute) {
+      const [userId, medicationId, dayKey] = key.split("|");
+      try {
+        await recomputeMedicationComplianceForDay(
+          userId,
+          medicationId,
+          dayKey,
+          await userTimezone(userId),
+        );
+        summary.rollupsRecomputed += 1;
+      } catch (err) {
+        console.error(
+          `${TAG} rollup recompute failed for ${key}: ` +
+            `${err instanceof Error ? err.message : String(err)}`,
+        );
+      }
+    }
+  }
+
+  // ───────────────────────────────────────────────────────────────────
+  // Summary
+  // ───────────────────────────────────────────────────────────────────
+  console.log(`\n${TAG} ${opts.fix ? "DONE" : "DRY-RUN — nothing changed"}`);
+  console.log(`  duplicate slot groups:        ${summary.duplicateGroups}`);
+  console.log(`  duplicate rows tombstoned:    ${summary.rowsTombstoned}`);
+  console.log(`  implausible taken_at rows:    ${summary.implausibleRows}`);
+  console.log(`  implausible rows tombstoned:  ${summary.implausibleTombstoned}`);
+  console.log(`  rollup days recomputed:       ${summary.rollupsRecomputed}`);
+}
+
+main()
+  .catch((err) => {
+    console.error(`${TAG} fatal error:`, err);
+    process.exit(1);
+  })
+  .finally(async () => {
+    await prisma.$disconnect();
+  });