diff --git a/apps/api/src/__tests__/groomerIsolation.test.ts b/apps/api/src/__tests__/groomerIsolation.test.ts
new file mode 100644
index 0000000..d8cec1a
--- /dev/null
+++ b/apps/api/src/__tests__/groomerIsolation.test.ts
@@ -0,0 +1,104 @@
+/**
+ * Groomer Isolation Tests
+ *
+ * Validates row-level data scoping for the groomer role.
+ *
+ * The role guard tests verify the core groomer identification logic.
+ * Integration tests with the real database validate the full filter behavior.
+ */
+
+import { describe, it, expect } from "vitest";
+import type { StaffRow } from "../middleware/rbac.js";
+
+// ─── Mock staff ───────────────────────────────────────────────────────────────
+
+const MANAGER: StaffRow = {
+  id: "staff-manager-id",
+  oidcSub: "oidc-manager-sub",
+  role: "manager",
+  name: "Manager McManager",
+  email: "manager@example.com",
+  active: true,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  icalToken: null,
+};
+
+const GROOMER: StaffRow = {
+  ...MANAGER,
+  id: "staff-groomer-id",
+  oidcSub: "oidc-groomer-sub",
+  role: "groomer",
+  name: "Groomer Gary",
+  email: "groomer@example.com",
+};
+
+const RECEPTIONIST: StaffRow = {
+  ...MANAGER,
+  id: "staff-receptionist-id",
+  oidcSub: "oidc-receptionist-sub",
+  role: "receptionist",
+  name: "Receptionist Rita",
+  email: "receptionist@example.com",
+};
+
+// ─── Role guard ──────────────────────────────────────────────────────────────
+
+/**
+ * The isGroomer guard (staffRow?.role === "groomer") is the foundation of
+ * all row-level filtering in appointments.ts, clients.ts, and pets.ts.
+ * These tests verify it handles all roles correctly.
+ */
+describe("Groomer role guard", () => {
+  const isGroomer = (s: StaffRow | undefined) => s?.role === "groomer";
+
+  it("manager is not groomer", () => expect(isGroomer(MANAGER)).toBe(false));
+  it("receptionist is not groomer", () => expect(isGroomer(RECEPTIONIST)).toBe(false));
+  it("groomer is groomer", () => expect(isGroomer(GROOMER)).toBe(true));
+
+  /** Safe fallback when staff context is not set (e.g., missing auth middleware) */
+  it("undefined staff is not groomer", () => expect(isGroomer(undefined)).toBe(false));
+});
+
+// ─── Groomer filter data shapes ───────────────────────────────────────────────
+
+/**
+ * These constants match the shape used in route handlers to validate
+ * the groomer filter conditions:
+ *   or(eq(appointments.staffId, staffRow.id), eq(appointments.batherStaffId, staffRow.id))
+ * This verifies the groomer can see appointments they own OR bathe.
+ */
+describe("Groomer appointment filter data", () => {
+  const GROOMER_APPT = { id: "appt-1", staffId: GROOMER.id, batherStaffId: null as string | null };
+  const BATHER_APPT = { id: "appt-2", staffId: MANAGER.id, batherStaffId: GROOMER.id };
+  const OTHER_APPT = { id: "appt-3", staffId: MANAGER.id, batherStaffId: null as string | null };
+
+  it("groomer appointment has groomer staffId", () => {
+    expect(GROOMER_APPT.staffId).toBe(GROOMER.id);
+    expect(GROOMER_APPT.batherStaffId).toBeNull();
+  });
+
+  it("groomer can see appointment where they are the bather", () => {
+    expect(BATHER_APPT.batherStaffId).toBe(GROOMER.id);
+    expect(BATHER_APPT.staffId).toBe(MANAGER.id);
+  });
+
+  it("other appointment is not assigned to groomer", () => {
+    expect(OTHER_APPT.staffId).toBe(MANAGER.id);
+    expect(OTHER_APPT.batherStaffId).toBeNull();
+  });
+
+  it("filter: groomer sees only their appointments", () => {
+    const all = [GROOMER_APPT, BATHER_APPT, OTHER_APPT];
+    const groomerView = all.filter(
+      (a) => a.staffId === GROOMER.id || a.batherStaffId === GROOMER.id
+    );
+    expect(groomerView).toHaveLength(2);
+    expect(groomerView.map((a) => a.id)).toEqual(["appt-1", "appt-2"]);
+  });
+
+  it("filter: manager sees all appointments", () => {
+    const all = [GROOMER_APPT, BATHER_APPT, OTHER_APPT];
+    expect(all).toHaveLength(3);
+  });
+});
diff --git a/apps/api/src/__tests__/petPhotos.test.ts b/apps/api/src/__tests__/petPhotos.test.ts
index 84a930c..1854cc6 100644
--- a/apps/api/src/__tests__/petPhotos.test.ts
+++ b/apps/api/src/__tests__/petPhotos.test.ts
@@ -13,6 +13,7 @@ const MANAGER: StaffRow = {
   active: true,
   createdAt: new Date(),
   updatedAt: new Date(),
+  icalToken: null,
 };
 
 const GROOMER: StaffRow = {
diff --git a/apps/api/src/__tests__/rbac.test.ts b/apps/api/src/__tests__/rbac.test.ts
index c27db51..e1bd6b3 100644
--- a/apps/api/src/__tests__/rbac.test.ts
+++ b/apps/api/src/__tests__/rbac.test.ts
@@ -14,6 +14,7 @@ const MANAGER: StaffRow = {
   active: true,
   createdAt: new Date(),
   updatedAt: new Date(),
+  icalToken: null,
 };
 
 const RECEPTIONIST: StaffRow = {
diff --git a/apps/api/src/routes/appointments.ts b/apps/api/src/routes/appointments.ts
index edecf8d..c693325 100644
--- a/apps/api/src/routes/appointments.ts
+++ b/apps/api/src/routes/appointments.ts
@@ -10,6 +10,7 @@ import {
   lt,
   lte,
   ne,
+  or,
   appointments,
   clients,
   pets,
@@ -20,8 +21,9 @@ import {
 } from "@groombook/db";
 import { buildConfirmationEmail, sendEmail } from "../services/email.js";
 import { notifyWaitlistForAppointment } from "../services/waitlistNotify.js";
+import type { AppEnv } from "../middleware/rbac.js";
 
-export const appointmentsRouter = new Hono();
+export const appointmentsRouter = new Hono<AppEnv>();
 
 const createAppointmentSchema = z.object({
   clientId: z.string().uuid(),
@@ -63,18 +65,31 @@ const updateAppointmentSchema = z.object({
   cascadeMode: z.enum(["this_only", "this_and_future", "all"]).optional(),
 });
 
-// List appointments, optionally filtered by date range or staffId
+// List appointments, optionally filtered by date range or staffId.
+// Groomers see only their own appointments (staffId or batherStaffId).
 appointmentsRouter.get("/", async (c) => {
   const db = getDb();
   const from = c.req.query("from");
   const to = c.req.query("to");
   const staffId = c.req.query("staffId");
+  const staffRow = c.get("staff");
+  const isGroomer = staffRow?.role === "groomer";
 
   const conditions = [];
   if (from) conditions.push(gte(appointments.startTime, new Date(from)));
   if (to) conditions.push(lte(appointments.startTime, new Date(to)));
   if (staffId) conditions.push(eq(appointments.staffId, staffId));
 
+  // Groomer: restrict to their own appointments (as groomer or bather)
+  if (isGroomer) {
+    conditions.push(
+      or(
+        eq(appointments.staffId, staffRow.id),
+        eq(appointments.batherStaffId, staffRow.id)
+      )
+    );
+  }
+
   const rows =
     conditions.length > 0
       ? await db
@@ -92,11 +107,17 @@ appointmentsRouter.get("/", async (c) => {
 
 appointmentsRouter.get("/:id", async (c) => {
   const db = getDb();
+  const staffRow = c.get("staff");
+  const isGroomer = staffRow?.role === "groomer";
   const [row] = await db
     .select()
     .from(appointments)
     .where(eq(appointments.id, c.req.param("id")));
   if (!row) return c.json({ error: "Not found" }, 404);
+  // Groomer: 403 if not assigned as groomer or bather
+  if (isGroomer && row.staffId !== staffRow.id && row.batherStaffId !== staffRow.id) {
+    return c.json({ error: "Forbidden" }, 403);
+  }
   return c.json(row);
 });
 
diff --git a/apps/api/src/routes/clients.ts b/apps/api/src/routes/clients.ts
index 90313a2..d569247 100644
--- a/apps/api/src/routes/clients.ts
+++ b/apps/api/src/routes/clients.ts
@@ -1,9 +1,10 @@
 import { Hono } from "hono";
 import { zValidator } from "@hono/zod-validator";
 import { z } from "zod";
-import { eq, getDb, clients } from "@groombook/db";
+import { and, eq, exists, getDb, or, clients, appointments } from "@groombook/db";
+import type { AppEnv } from "../middleware/rbac.js";
 
-export const clientsRouter = new Hono();
+export const clientsRouter = new Hono<AppEnv>();
 
 const createClientSchema = z.object({
   name: z.string().min(1).max(200),
@@ -14,25 +15,72 @@ const createClientSchema = z.object({
 });
 
 
-// List clients — defaults to active only, ?includeDisabled=true shows all
+// List clients — defaults to active only, ?includeDisabled=true shows all.
+// Groomers see only clients with ≥1 appointment assigned to them.
 clientsRouter.get("/", async (c) => {
   const db = getDb();
   const includeDisabled = c.req.query("includeDisabled") === "true";
-  const query = includeDisabled
-    ? db.select().from(clients).orderBy(clients.name)
-    : db.select().from(clients).where(eq(clients.status, "active")).orderBy(clients.name);
-  const rows = await query;
+  const staffRow = c.get("staff");
+  const isGroomer = staffRow?.role === "groomer";
+
+  // Groomer: subquery for clients with an appointment for this groomer
+  const groomerApptFilter = isGroomer
+    ? exists(
+        db
+          .select({ id: appointments.id })
+          .from(appointments)
+          .where(
+            and(
+              eq(appointments.clientId, clients.id),
+              or(
+                eq(appointments.staffId, staffRow.id),
+                eq(appointments.batherStaffId, staffRow.id)
+              )
+            )
+          )
+      )
+    : undefined;
+
+  const conditions = [];
+  if (!includeDisabled) conditions.push(eq(clients.status, "active"));
+  if (groomerApptFilter) conditions.push(groomerApptFilter);
+
+  const rows = await db
+    .select()
+    .from(clients)
+    .where(conditions.length > 0 ? and(...conditions) : undefined)
+    .orderBy(clients.name);
   return c.json(rows);
 });
 
 // Get a single client
 clientsRouter.get("/:id", async (c) => {
   const db = getDb();
+  const clientId = c.req.param("id");
+  const staffRow = c.get("staff");
+  const isGroomer = staffRow?.role === "groomer";
   const [row] = await db
     .select()
     .from(clients)
-    .where(eq(clients.id, c.req.param("id")));
+    .where(eq(clients.id, clientId));
   if (!row) return c.json({ error: "Not found" }, 404);
+  // Groomer: 403 if no appointment linkage to this client
+  if (isGroomer) {
+    const [linkage] = await db
+      .select({ id: appointments.id })
+      .from(appointments)
+      .where(
+        and(
+          eq(appointments.clientId, clientId),
+          or(
+            eq(appointments.staffId, staffRow.id),
+            eq(appointments.batherStaffId, staffRow.id)
+          )
+        )
+      )
+      .limit(1);
+    if (!linkage) return c.json({ error: "Forbidden" }, 403);
+  }
   return c.json(row);
 });
 
diff --git a/apps/api/src/routes/pets.ts b/apps/api/src/routes/pets.ts
index 6e2e8e6..5bcb20e 100644
--- a/apps/api/src/routes/pets.ts
+++ b/apps/api/src/routes/pets.ts
@@ -1,7 +1,7 @@
 import { Hono } from "hono";
 import { zValidator } from "@hono/zod-validator";
 import { z } from "zod";
-import { eq, getDb, pets } from "@groombook/db";
+import { and, eq, exists, getDb, or, pets, appointments } from "@groombook/db";
 import type { AppEnv } from "../middleware/rbac.js";
 import {
   getPresignedUploadUrl,
@@ -28,25 +28,70 @@ const createPetSchema = z.object({
 
 const updatePetSchema = createPetSchema.partial().omit({ clientId: true });
 
+// List pets, optionally filtered by clientId.
+// Groomers see only pets owned by clients with ≥1 appointment for this groomer.
 petsRouter.get("/", async (c) => {
   const db = getDb();
   const clientId = c.req.query("clientId");
-  const query = db.select().from(pets);
-  if (clientId) {
-    const rows = await query.where(eq(pets.clientId, clientId));
-    return c.json(rows);
-  }
-  const rows = await query;
+  const staffRow = c.get("staff");
+  const isGroomer = staffRow?.role === "groomer";
+
+  // Groomer: filter to pets whose client has an appointment for this groomer
+  const groomerClientFilter = isGroomer
+    ? exists(
+        db
+          .select({ id: appointments.id })
+          .from(appointments)
+          .where(
+            and(
+              eq(appointments.clientId, pets.clientId),
+              or(
+                eq(appointments.staffId, staffRow.id),
+                eq(appointments.batherStaffId, staffRow.id)
+              )
+            )
+          )
+      )
+    : undefined;
+
+  const conditions = [];
+  if (clientId) conditions.push(eq(pets.clientId, clientId));
+  if (groomerClientFilter) conditions.push(groomerClientFilter);
+
+  const rows = await db
+    .select()
+    .from(pets)
+    .where(conditions.length > 0 ? and(...conditions) : undefined);
   return c.json(rows);
 });
 
 petsRouter.get("/:id", async (c) => {
   const db = getDb();
+  const petId = c.req.param("id");
+  const staffRow = c.get("staff");
+  const isGroomer = staffRow?.role === "groomer";
   const [row] = await db
     .select()
     .from(pets)
-    .where(eq(pets.id, c.req.param("id")));
+    .where(eq(pets.id, petId));
   if (!row) return c.json({ error: "Not found" }, 404);
+  // Groomer: 403 if no appointment linkage to this pet's client
+  if (isGroomer) {
+    const [linkage] = await db
+      .select({ id: appointments.id })
+      .from(appointments)
+      .where(
+        and(
+          eq(appointments.clientId, row.clientId),
+          or(
+            eq(appointments.staffId, staffRow.id),
+            eq(appointments.batherStaffId, staffRow.id)
+          )
+        )
+      )
+      .limit(1);
+    if (!linkage) return c.json({ error: "Forbidden" }, 403);
+  }
   return c.json(row);
 });
 
diff --git a/packages/db/src/factories.ts b/packages/db/src/factories.ts
index 7e4d735..693a90f 100644
--- a/packages/db/src/factories.ts
+++ b/packages/db/src/factories.ts
@@ -54,6 +54,7 @@ export function buildStaff(overrides: Partial<StaffRow> = {}): StaffRow {
     active: true,
     createdAt: new Date("2025-01-01T00:00:00Z"),
     updatedAt: new Date("2025-01-01T00:00:00Z"),
+    icalToken: null,
     ...overrides,
   };
 }
diff --git a/packages/db/src/index.ts b/packages/db/src/index.ts
index 0ba0d5e..61ec021 100644
--- a/packages/db/src/index.ts
+++ b/packages/db/src/index.ts
@@ -3,7 +3,7 @@ import postgres from "postgres";
 import * as schema from "./schema.js";
 
 export * from "./schema.js";
-export { and, asc, desc, eq, gte, gt, ilike, lt, lte, ne, or, sql } from "drizzle-orm";
+export { and, asc, desc, eq, exists, gte, gt, ilike, lt, lte, ne, or, sql } from "drizzle-orm";
 
 let _db: ReturnType<typeof drizzle> | null = null;
 
diff --git a/packages/db/src/schema.ts b/packages/db/src/schema.ts
index 676602b..ddcddc7 100644
--- a/packages/db/src/schema.ts
+++ b/packages/db/src/schema.ts
@@ -106,6 +106,8 @@ export const staff = pgTable("staff", {
   oidcSub: text("oidc_sub").unique(),
   role: staffRoleEnum("role").notNull().default("groomer"),
   active: boolean("active").notNull().default(true),
+  // Token for iCal calendar feed subscription (no auth required)
+  icalToken: text("ical_token").unique(),
   createdAt: timestamp("created_at").notNull().defaultNow(),
   updatedAt: timestamp("updated_at").notNull().defaultNow(),
 });