diff --git a/src/__tests__/petProfileSummary.test.ts b/src/__tests__/petProfileSummary.test.ts
new file mode 100644
index 0000000..d3d529f
--- /dev/null
+++ b/src/__tests__/petProfileSummary.test.ts
@@ -0,0 +1,469 @@
+/**
+ * Pet Profile Summary Tests
+ *
+ * Covers GET /api/pets/:id/profile-summary in the deployed tree
+ * (root src/). The headline cases validate the GRO-2013 owner-bypass:
+ * a customer who is auto-provisioned as a `groomer` staff row by rbac.ts
+ * (with no appointment linkage) may still read their own pet's summary
+ * when they supply a valid X-Impersonation-Session-Id whose clientId
+ * matches the pet's clientId.
+ *
+ * Deployed tree: src/routes/pets.ts. This test mirrors the live handler
+ * (which queries the `appointments` table for visit history, not
+ * `groomingVisitLogs`).
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { Hono } from "hono";
+import type { AppEnv, StaffRow } from "../middleware/rbac.js";
+
+// ─── Mock staff fixtures ──────────────────────────────────────────────────────
+
+const MANAGER: StaffRow = {
+  id: "staff-manager-id",
+  oidcSub: "oidc-manager-sub",
+  userId: null,
+  role: "manager",
+  isSuperUser: true,
+  name: "Manager McManager",
+  email: "manager@example.com",
+  active: true,
+  icalToken: null,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+};
+
+const GROOMER: StaffRow = {
+  ...MANAGER,
+  id: "staff-groomer-id",
+  oidcSub: "oidc-groomer-sub",
+  role: "groomer",
+  name: "Groomer Gary",
+  email: "groomer@example.com",
+};
+
+/**
+ * Mirrors the auto-provisioned "groomer" staff row rbac.ts creates for an
+ * OIDC user (e.g. uat-customer@groombook.dev) on first login: role=groomer,
+ * no appointment linkage.
+ */
+const CUSTOMER_STAFF: StaffRow = {
+  ...MANAGER,
+  id: "staff-customer-id",
+  oidcSub: null,
+  userId: "user-customer-id",
+  role: "groomer",
+  name: "UAT Customer",
+  email: "uat-customer@groombook.dev",
+};
+
+// ─── Mutable mock state ───────────────────────────────────────────────────────
+
+const CLIENT_ID = "c0000001-0000-0000-0000-000000000001";
+const PET_ID = "c0000001-0000-0000-0000-000000000002";
+const OTHER_CLIENT_PET_ID = "c0000002-0000-0000-0000-000000000099";
+
+const futureDate = () => new Date(Date.now() + 30 * 60_000);
+const pastDate = () => new Date(Date.now() - 5 * 60_000);
+
+function makePet(overrides: Record<string, unknown> = {}) {
+  return {
+    id: PET_ID,
+    clientId: CLIENT_ID,
+    name: "Biscuit",
+    species: "dog",
+    breed: "Golden Retriever",
+    weightKg: "30.00",
+    dateOfBirth: null,
+    healthAlerts: null,
+    groomingNotes: null,
+    cutStyle: null,
+    shampooPreference: null,
+    specialCareNotes: null,
+    customFields: {},
+    petSizeCategory: "large",
+    coatType: "double",
+    photoKey: null,
+    photoUploadedAt: null,
+    createdAt: new Date("2024-01-01"),
+    updatedAt: new Date("2024-01-01"),
+    ...overrides,
+  };
+}
+
+function makeAppointment(overrides: Record<string, unknown> = {}) {
+  return {
+    id: "appt-1",
+    clientId: CLIENT_ID,
+    petId: PET_ID,
+    serviceId: "service-1",
+    staffId: GROOMER.id,
+    batherStaffId: null,
+    status: "completed",
+    startTime: new Date("2024-06-01T09:00:00Z"),
+    endTime: new Date("2024-06-01T11:00:00Z"),
+    notes: null,
+    priceCents: 6000,
+    seriesId: null,
+    seriesIndex: null,
+    groupId: null,
+    confirmationStatus: "confirmed",
+    confirmedAt: null,
+    cancelledAt: null,
+    confirmationToken: null,
+    customerNotes: null,
+    createdAt: new Date("2024-05-15"),
+    updatedAt: new Date("2024-05-15"),
+    ...overrides,
+  };
+}
+
+function makeService(overrides: Record<string, unknown> = {}) {
+  return {
+    id: "service-1",
+    name: "Full Groom",
+    description: null,
+    basePriceCents: 6000,
+    durationMinutes: 120,
+    active: true,
+    createdAt: new Date(),
+    updatedAt: new Date(),
+    ...overrides,
+  };
+}
+
+function makeSession(overrides: Record<string, unknown> = {}) {
+  return {
+    id: "sess-owner",
+    staffId: CUSTOMER_STAFF.id,
+    clientId: CLIENT_ID,
+    reason: "sso-bridge",
+    status: "active",
+    startedAt: new Date(),
+    endedAt: null,
+    expiresAt: futureDate(),
+    createdAt: new Date(),
+    ...overrides,
+  };
+}
+
+// ─── DB mock state ────────────────────────────────────────────────────────────
+
+let petsTable: Record<string, unknown>[];
+let appointmentsTable: Record<string, unknown>[];
+let servicesTable: Record<string, unknown>[];
+let sessionsTable: Record<string, unknown>[];
+
+// selectQueue: queries resolve in FIFO order. Each .from(table) result
+// returns a chain that resolves to the next queued row set on a terminal
+// call (.where()/.orderBy()/.limit()).
+let selectQueue: Array<{ table: string; rows: unknown[] }> = [];
+
+function enqueue(table: string, rows: unknown[] = []) {
+  selectQueue.push({ table, rows });
+}
+
+function resetMock() {
+  petsTable = [makePet()];
+  appointmentsTable = [makeAppointment()];
+  servicesTable = [makeService()];
+  sessionsTable = [makeSession()];
+  selectQueue = [];
+}
+
+// ─── Module mocks ─────────────────────────────────────────────────────────────
+
+vi.mock("@groombook/db", () => {
+  function makeTable(name: string) {
+    return new Proxy(
+      { _name: name },
+      {
+        get(target, prop) {
+          if (prop === "_name") return name;
+          if (prop === "$inferSelect") return {};
+          return { table: name, column: prop };
+        },
+      }
+    );
+  }
+
+  function sqlMock(_strings: TemplateStringsArray, ..._params: unknown[]) {
+    const queryString = _strings[0];
+    return {
+      queryChunks: [queryString],
+      as: (alias: string) => ({
+        queryChunks: [queryString],
+        fieldAlias: alias,
+        getSQL() { return this.queryChunks; },
+      }),
+    };
+  }
+
+  function takeQueuedRows(tableName: string): unknown[] {
+    const next = selectQueue.shift();
+    if (next && next.table === tableName) return next.rows;
+    return [];
+  }
+
+  // Wrap a finalised result in a Proxy that exposes chainable methods
+  // and the resolved rows. Each call to a chainable method (where/orderBy/
+  // limit/...) returns the SAME rows so the route's natural await on the
+  // chain resolves to the queued data.
+  function wrapRows(rows: unknown[]): unknown {
+    return new Proxy(rows, {
+      get(target, prop: string | symbol) {
+        if (prop === "where" || prop === "orderBy" || prop === "limit"
+          || prop === "leftJoin" || prop === "innerJoin" || prop === "from") {
+          return () => wrapRows(rows);
+        }
+        if (prop === "then") {
+          return (onFulfilled?: (v: unknown) => unknown, onRejected?: (e: unknown) => unknown) =>
+            Promise.resolve(rows).then(onFulfilled, onRejected);
+        }
+        if (prop === Symbol.iterator) {
+          return function* () { for (const v of target) yield v; };
+        }
+        if (prop === Symbol.asyncIterator) {
+          return async function* () { for (const v of target) yield v; };
+        }
+        // @ts-expect-error proxy access
+        return target[prop];
+      },
+    });
+  }
+
+  return {
+    getDb: () => ({
+      select: (_cols?: Record<string, unknown>) => ({
+        from: (table: { _name?: string }) => wrapRows(takeQueuedRows(table._name ?? "")),
+      }),
+      insert: () => ({ values: () => ({ returning: () => [{}] }) }),
+      update: () => ({ set: () => ({ where: () => ({ returning: () => [{}] }) }) }),
+      delete: () => ({ where: () => ({ returning: () => [{}] }) }),
+    }),
+    pets: makeTable("pets"),
+    appointments: makeTable("appointments"),
+    staff: makeTable("staff"),
+    services: makeTable("services"),
+    impersonationSessions: makeTable("impersonationSessions"),
+    and: vi.fn((..._args: unknown[]) => ({})),
+    desc: vi.fn((c: unknown) => c),
+    eq: vi.fn((_a: unknown, _b: unknown) => ({})),
+    exists: vi.fn(() => true),
+    or: vi.fn((..._args: unknown[]) => ({})),
+    sql: sqlMock,
+  };
+});
+
+vi.mock("../lib/s3.js", () => ({
+  getPresignedUploadUrl: vi.fn(),
+  getPresignedGetUrl: vi.fn(),
+  deleteObject: vi.fn(),
+}));
+
+// ─── Import after mocks are set up ────────────────────────────────────────────
+
+const { petsRouter } = await import("../routes/pets.js");
+
+// ─── App builder ──────────────────────────────────────────────────────────────
+
+function buildApp(staffRow: StaffRow) {
+  const app = new Hono<AppEnv>();
+  app.use("*", async (c, next) => {
+    c.set("jwtPayload", { sub: staffRow.oidcSub ?? staffRow.userId ?? "" });
+    c.set("staff", staffRow);
+    await next();
+  });
+  app.route("/pets", petsRouter);
+  return app;
+}
+
+// ─── Reset before each test ───────────────────────────────────────────────────
+
+beforeEach(() => {
+  resetMock();
+  vi.clearAllMocks();
+});
+
+// ─── Tests ────────────────────────────────────────────────────────────────────
+
+describe("GET /:id/profile-summary — basic access", () => {
+  it("returns 404 when the pet does not exist", async () => {
+    petsTable = [];
+    enqueue("pets", []);
+    const app = buildApp(MANAGER);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(404);
+  });
+
+  it("returns 200 with aggregated profile for a manager", async () => {
+    // Query order: pets, recent history, visit count, upcoming
+    enqueue("pets", petsTable);
+    enqueue("appointments", appointmentsTable);
+    enqueue("appointments", [{ count: 1 }]);
+    enqueue("appointments", []);
+
+    const app = buildApp(MANAGER);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(200);
+    const body = await res.json();
+    expect(body.id).toBe(PET_ID);
+    expect(body.name).toBe("Biscuit");
+    expect(body.recentGroomingHistory).toBeInstanceOf(Array);
+    expect(body.visitCount).toBe(1);
+    expect(body.upcomingAppointment).toBeNull();
+  });
+
+  it("returns 200 for a groomer with appointment linkage to the pet's client", async () => {
+    // Query order: pets, linkage check, recent history, visit count, upcoming
+    enqueue("pets", petsTable);
+    enqueue("appointments", [{ id: "appt-1" }]); // linkage found
+    enqueue("appointments", appointmentsTable); // history
+    enqueue("appointments", [{ count: 1 }]);
+    enqueue("appointments", []);
+
+    const app = buildApp(GROOMER);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(200);
+  });
+
+  it("returns 403 for a groomer with no appointment linkage and no bypass header", async () => {
+    // Query order: pets, linkage check (returns empty → 403)
+    enqueue("pets", petsTable);
+    enqueue("appointments", []); // no linkage
+
+    const app = buildApp(GROOMER);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(403);
+  });
+});
+
+// ─── GRO-2013 owner-bypass ────────────────────────────────────────────────────
+
+describe("GET /:id/profile-summary — owner-bypass (GRO-2013)", () => {
+  it("customer-as-groomer with valid active session for pet's client returns 200", async () => {
+    // Query order: pets, session lookup (found, active, future), recent history,
+    // visit count, upcoming
+    enqueue("pets", petsTable);
+    enqueue("impersonationSessions", sessionsTable); // active session found
+    enqueue("appointments", appointmentsTable);
+    enqueue("appointments", [{ count: 1 }]);
+    enqueue("appointments", []);
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`, {
+      headers: { "X-Impersonation-Session-Id": "sess-owner" },
+    });
+    expect(res.status).toBe(200);
+    const body = await res.json();
+    expect(body.id).toBe(PET_ID);
+  });
+
+  it("customer-as-groomer with no header still gets 403 (no bypass)", async () => {
+    // Query order: pets, session lookup (header missing → returns [], 403)
+    enqueue("pets", petsTable);
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(403);
+  });
+
+  it("customer-as-groomer with session for a DIFFERENT client gets 403 (cross-tenant blocked)", async () => {
+    // Session exists but clientId !== pet.clientId → bypass does not apply
+    // → falls through to groomer linkage check → no linkage → 403
+    enqueue("pets", petsTable);
+    enqueue("impersonationSessions", [
+      makeSession({
+        id: "sess-other-client",
+        clientId: "c0000000-0000-0000-0000-000000000099", // different from CLIENT_ID
+      }),
+    ]);
+    enqueue("appointments", []); // no linkage → 403
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`, {
+      headers: { "X-Impersonation-Session-Id": "sess-other-client" },
+    });
+    expect(res.status).toBe(403);
+  });
+
+  it("customer-as-groomer with expired session still gets 403", async () => {
+    enqueue("pets", petsTable);
+    enqueue("impersonationSessions", [
+      makeSession({ id: "sess-expired", expiresAt: pastDate() }),
+    ]);
+    enqueue("appointments", []); // no linkage → 403
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`, {
+      headers: { "X-Impersonation-Session-Id": "sess-expired" },
+    });
+    expect(res.status).toBe(403);
+  });
+
+  it("customer-as-groomer with ended (status != active) session still gets 403", async () => {
+    enqueue("pets", petsTable);
+    enqueue("impersonationSessions", [
+      makeSession({ id: "sess-ended", status: "ended" }),
+    ]);
+    enqueue("appointments", []); // no linkage → 403
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`, {
+      headers: { "X-Impersonation-Session-Id": "sess-ended" },
+    });
+    expect(res.status).toBe(403);
+  });
+
+  it("customer-as-groomer with unknown session id still gets 403", async () => {
+    enqueue("pets", petsTable);
+    enqueue("impersonationSessions", []); // session not found
+    enqueue("appointments", []); // no linkage → 403
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`, {
+      headers: { "X-Impersonation-Session-Id": "sess-unknown" },
+    });
+    expect(res.status).toBe(403);
+  });
+
+  it("manager does NOT need the impersonation header (existing role check still works)", async () => {
+    enqueue("pets", petsTable);
+    enqueue("appointments", appointmentsTable);
+    enqueue("appointments", [{ count: 1 }]);
+    enqueue("appointments", []);
+
+    const app = buildApp(MANAGER);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(200);
+  });
+
+  it("groomer with linkage to pet's client still works (regression — no regression from bypass)", async () => {
+    enqueue("pets", petsTable);
+    enqueue("appointments", [{ id: "appt-1" }]); // linkage found
+    enqueue("appointments", appointmentsTable);
+    enqueue("appointments", [{ count: 1 }]);
+    enqueue("appointments", []);
+
+    const app = buildApp(GROOMER);
+    const res = await app.request(`/pets/${PET_ID}/profile-summary`);
+    expect(res.status).toBe(200);
+  });
+
+  it("owner-bypass: customer cannot view another client's pet (cross-tenant block)", async () => {
+    // The customer has a valid session for CLIENT_ID, but the pet belongs
+    // to a different client → isOwner=false → falls through to groomer
+    // linkage check → 403.
+    enqueue("pets", [
+      makePet({ id: OTHER_CLIENT_PET_ID, clientId: "c0000002-0000-0000-0000-000000000002" }),
+    ]);
+    enqueue("impersonationSessions", sessionsTable); // valid session, but for CLIENT_ID
+    enqueue("appointments", []); // no linkage → 403
+
+    const app = buildApp(CUSTOMER_STAFF);
+    const res = await app.request(`/pets/${OTHER_CLIENT_PET_ID}/profile-summary`, {
+      headers: { "X-Impersonation-Session-Id": "sess-owner" },
+    });
+    expect(res.status).toBe(403);
+  });
+});
diff --git a/src/routes/pets.ts b/src/routes/pets.ts
index ffe494c..a16582c 100644
--- a/src/routes/pets.ts
+++ b/src/routes/pets.ts
@@ -7,6 +7,7 @@ import {
   eq,
   exists,
   getDb,
+  impersonationSessions,
   or,
   pets,
   appointments,
@@ -109,6 +110,35 @@ petsRouter.get("/:id", async (c) => {
   return c.json(row);
 });
 
+/**
+ * Resolves the clientId from the X-Impersonation-Session-Id header, if present and active.
+ * Used by staff routes to allow a customer (auto-provisioned as a `groomer` staff row
+ * by rbac.ts) to access their own pet's data when they are the rightful owner.
+ *
+ * Returns null when the header is missing, the session is unknown/expired/ended, or the
+ * session exists but has no clientId — callers should treat null as "no owner-bypass".
+ */
+async function resolveImpersonationClientId(
+  db: ReturnType<typeof getDb>,
+  c: { req: { header: (name: string) => string | undefined } }
+): Promise<string | null> {
+  const sessionId = c.req.header("X-Impersonation-Session-Id");
+  if (!sessionId) return null;
+  const [session] = await db
+    .select({
+      clientId: impersonationSessions.clientId,
+      status: impersonationSessions.status,
+      expiresAt: impersonationSessions.expiresAt,
+    })
+    .from(impersonationSessions)
+    .where(eq(impersonationSessions.id, sessionId))
+    .limit(1);
+  if (!session) return null;
+  if (session.status !== "active") return null;
+  if (session.expiresAt <= new Date()) return null;
+  return session.clientId;
+}
+
 petsRouter.get("/:id/profile-summary", async (c) => {
   const db = getDb();
   const petId = c.req.param("id");
@@ -119,8 +149,18 @@ petsRouter.get("/:id/profile-summary", async (c) => {
   const [pet] = await db.select().from(pets).where(eq(pets.id, petId));
   if (!pet) return c.json({ error: "Not found" }, 404);
 
-  // Groomer RBAC: check appointment linkage to this pet's client
+  // Owner-bypass (GRO-2013): a customer who supplies a valid
+  // X-Impersonation-Session-Id for the pet's owning client may read their
+  // own pet's summary, even though rbac.ts auto-provisions them as a
+  // `groomer` staff row with no appointment linkage.
+  let isOwner = false;
   if (isGroomer) {
+    const ownerClientId = await resolveImpersonationClientId(db, c);
+    isOwner = !!ownerClientId && ownerClientId === pet.clientId;
+  }
+
+  // Groomer RBAC: check appointment linkage to this pet's client
+  if (isGroomer && !isOwner) {
     const [linkage] = await db
       .select({ id: appointments.id })
       .from(appointments)