diff --git a/apps/api/src/__tests__/petsExtendedFields.test.ts b/apps/api/src/__tests__/petsExtendedFields.test.ts
index a1c64a8..3425234 100644
--- a/apps/api/src/__tests__/petsExtendedFields.test.ts
+++ b/apps/api/src/__tests__/petsExtendedFields.test.ts
@@ -2,6 +2,7 @@ import { describe, it, expect, vi, beforeEach } from "vitest";
 import { Hono } from "hono";
 import type { AppEnv, StaffRow } from "../middleware/rbac.js";
 import { petsRouter } from "../routes/pets.js";
+import { and, eq, exists, or } from "../db/index.js";
 
 // ─── Mock staff fixtures ──────────────────────────────────────────────────────
 
@@ -164,10 +165,10 @@ vi.mock("../db", async (importOriginal) => {
     }),
     pets,
     appointments,
-and: (...conds: unknown[]) => conds,
-    eq: (col: unknown, val: unknown) => ({ col, val }),
-    exists: (q: unknown) => q,
-    or: (...conds: unknown[]) => conds,
+and: db.and,
+    eq: db.eq,
+    exists: db.exists,
+    or: db.or,
   };
 });
 
diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index b9ccd84..0b53141 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -26,6 +26,7 @@ import { getDb, businessSettings, eq, staff } from "./db/index.js";
 import { authMiddleware } from "./middleware/auth.js";
 import { resolveStaffMiddleware, requireRole, requireRoleOrSuperUser, requireSuperUser } from "./middleware/rbac.js";
 import { devRouter } from "./routes/dev.js";
+import { bufferRulesRouter } from "./routes/buffer-rules.js";
 import { adminSeedRouter } from "./routes/admin/seed.js";
 import { startReminderScheduler } from "./services/reminders.js";
 import { webhooksRouter } from "./routes/stripe-webhooks.js";
@@ -211,6 +212,7 @@ api.on(["GET"], "/staff/*", requireRole("manager", "receptionist", "groomer"));
 // Staff write routes: manager OR super-user (combined guard — avoids AND stacking)
 api.on(["POST", "PATCH", "DELETE"], "/staff/*", requireRoleOrSuperUser("manager"));
 api.use("/admin/*", requireRoleOrSuperUser("manager"));
+api.use("/buffer-rules/*", requireRole("manager"));
 api.use("/admin/settings/*", requireSuperUser());
 api.use("/reports/*", requireRole("manager"));
 api.use("/invoices/*", requireRole("manager", "groomer"));
@@ -268,6 +270,7 @@ api.route("/impersonation", impersonationRouter);
 api.route("/admin/settings", settingsRouter);
 api.route("/admin/auth-provider", authProviderRouter);
 api.route("/admin/seed", adminSeedRouter);
+api.route("/buffer-rules", bufferRulesRouter);
 api.route("/search", searchRouter);
 
 const port = Number(process.env.PORT ?? 3000);
diff --git a/apps/api/src/routes/buffer-rules.ts b/apps/api/src/routes/buffer-rules.ts
new file mode 100644
index 0000000..296fec2
--- /dev/null
+++ b/apps/api/src/routes/buffer-rules.ts
@@ -0,0 +1,124 @@
+import { Hono } from "hono";
+import { zValidator } from "@hono/zod-validator";
+import { z } from "zod/v3";
+import { and, eq, getDb, isNull } from "../db/index.js";
+import type { AppEnv } from "../middleware/rbac.js";
+import { bufferRules, services } from "../db/index.js";
+
+export const bufferRulesRouter = new Hono<AppEnv>();
+
+const createBufferRuleSchema = z.object({
+  serviceId: z.string().uuid(),
+  sizeCategory: z
+    .enum(["small", "medium", "large", "extra_large"])
+    .optional(),
+  coatType: z
+    .enum(["short", "medium", "long", "double", "wire", "silky", "curly", "hairless"])
+    .optional(),
+  bufferMinutes: z.number().int().positive(),
+});
+
+const updateBufferRuleSchema = z.object({
+  bufferMinutes: z.number().int().positive(),
+});
+
+// GET / — list all buffer rules, optionally filtered by serviceId
+bufferRulesRouter.get("/", async (c) => {
+  const db = getDb();
+  const serviceId = c.req.query("serviceId");
+
+  const conditions = [];
+  if (serviceId) conditions.push(eq(bufferRules.serviceId, serviceId));
+
+  const rows = await db
+    .select({
+      id: bufferRules.id,
+      serviceId: bufferRules.serviceId,
+      sizeCategory: bufferRules.sizeCategory,
+      coatType: bufferRules.coatType,
+      bufferMinutes: bufferRules.bufferMinutes,
+      createdAt: bufferRules.createdAt,
+      updatedAt: bufferRules.updatedAt,
+      serviceName: services.name,
+    })
+    .from(bufferRules)
+    .innerJoin(services, eq(bufferRules.serviceId, services.id))
+    .where(conditions.length > 0 ? and(...conditions) : undefined)
+    .orderBy(bufferRules.createdAt);
+
+  return c.json(rows);
+});
+
+// POST / — create a buffer rule
+bufferRulesRouter.post(
+  "/",
+  zValidator("json", createBufferRuleSchema),
+  async (c) => {
+    const db = getDb();
+    const body = c.req.valid("json");
+
+    // Validate serviceId exists
+    const [svc] = await db
+      .select({ id: services.id })
+      .from(services)
+      .where(eq(services.id, body.serviceId));
+    if (!svc) return c.json({ error: "Service not found" }, 404);
+
+    // Check for duplicate (service + size + coat)
+    const [existing] = await db
+      .select({ id: bufferRules.id })
+      .from(bufferRules)
+      .where(
+        and(
+          eq(bufferRules.serviceId, body.serviceId),
+          body.sizeCategory !== undefined
+            ? eq(bufferRules.sizeCategory, body.sizeCategory)
+            : isNull(bufferRules.sizeCategory),
+          body.coatType !== undefined
+            ? eq(bufferRules.coatType, body.coatType)
+            : isNull(bufferRules.coatType)
+        )
+      );
+    if (existing) return c.json({ error: "Duplicate rule for this service+size+coat combination" }, 409);
+
+    const [row] = await db
+      .insert(bufferRules)
+      .values({
+        serviceId: body.serviceId,
+        sizeCategory: body.sizeCategory ?? null,
+        coatType: body.coatType ?? null,
+        bufferMinutes: body.bufferMinutes,
+      })
+      .returning();
+
+    return c.json(row, 201);
+  }
+);
+
+// PATCH /:id — update bufferMinutes only
+bufferRulesRouter.patch(
+  "/:id",
+  zValidator("json", updateBufferRuleSchema),
+  async (c) => {
+    const db = getDb();
+    const body = c.req.valid("json");
+    const [row] = await db
+      .update(bufferRules)
+      .set({ bufferMinutes: body.bufferMinutes, updatedAt: new Date() })
+      .where(eq(bufferRules.id, c.req.param("id")))
+      .returning();
+    if (!row) return c.json({ error: "Not found" }, 404);
+    return c.json(row);
+  }
+);
+
+// DELETE /:id — delete a buffer rule
+bufferRulesRouter.delete("/:id", async (c) => {
+  const db = getDb();
+  const [row] = await db
+    .delete(bufferRules)
+    .where(eq(bufferRules.id, c.req.param("id")))
+    .returning();
+  if (!row) return c.json({ error: "Not found" }, 404);
+  return c.json({ ok: true });
+});
\ No newline at end of file
diff --git a/apps/api/src/routes/pets.ts b/apps/api/src/routes/pets.ts
index 2ac78fd..dbc5418 100644
--- a/apps/api/src/routes/pets.ts
+++ b/apps/api/src/routes/pets.ts
@@ -24,6 +24,7 @@ const createPetSchema = z.object({
   shampooPreference: z.string().max(500).optional(),
   specialCareNotes: z.string().max(2000).optional(),
   customFields: z.record(z.string(), z.string()).optional(),
+  sizeCategory: z.enum(["small", "medium", "large", "extra_large"]).optional(),
   coatType: z.enum(["short", "medium", "long", "double", "wire", "silky", "curly", "hairless"]).optional(),
   temperamentScore: z.number().int().min(1).max(5).optional(),
   temperamentFlags: z.array(z.string().max(100)).max(20).optional(),
diff --git a/apps/api/src/routes/services.ts b/apps/api/src/routes/services.ts
index 993cb96..3e47f4f 100644
--- a/apps/api/src/routes/services.ts
+++ b/apps/api/src/routes/services.ts
@@ -13,7 +13,9 @@ const createServiceSchema = z.object({
   active: z.boolean().default(true),
 });
 
-const updateServiceSchema = createServiceSchema.partial();
+const updateServiceSchema = createServiceSchema.partial().extend({
+  defaultBufferMinutes: z.number().int().min(0).optional(),
+});
 
 servicesRouter.get("/", async (c) => {
   const db = getDb();
diff --git a/apps/api/src/types/index.ts b/apps/api/src/types/index.ts
index 4f60f42..72f26ac 100644
--- a/apps/api/src/types/index.ts
+++ b/apps/api/src/types/index.ts
@@ -26,6 +26,19 @@ export interface Client {
   updatedAt: string;
 }
 
+// ─── Medical Alerts ────────────────────────────────────────────────────────────
+
+export type AlertSeverity = "low" | "medium" | "high";
+
+export interface MedicalAlert {
+  type: string;
+  description: string;
+  severity: AlertSeverity;
+}
+
+// ─── Pet Profile Summary ────────────────────────────────────────────────────
+
+export type CoatType = "short" | "medium" | "long" | "double" | "wire" | "silky" | "curly" | "hairless";
 export interface Pet {
   id: string;
   clientId: string;
diff --git a/packages/db/src/schema.ts b/packages/db/src/schema.ts
index 7ab60eb..bb3c8f6 100644
--- a/packages/db/src/schema.ts
+++ b/packages/db/src/schema.ts
@@ -116,6 +116,26 @@ export const verification = pgTable("verification", {
   updatedAt: timestamp("updated_at").notNull().defaultNow(),
 });
 
+// ─── Pet enums ─────────────────────────────────────────────────────────────────
+
+export const petSizeCategoryEnum = pgEnum("pet_size_category", [
+  "small",
+  "medium",
+  "large",
+  "extra_large",
+]);
+
+export const coatTypeEnum = pgEnum("coat_type", [
+  "short",
+  "medium",
+  "long",
+  "double",
+  "wire",
+  "silky",
+  "curly",
+  "hairless",
+]);
+
 // ─── Tables ───────────────────────────────────────────────────────────────────
 
 export const clients = pgTable(
@@ -178,6 +198,7 @@ export const services = pgTable("services", {
   durationMinutes: integer("duration_minutes").notNull(),
   defaultBufferMinutes: integer("default_buffer_minutes"),
   active: boolean("active").notNull().default(true),
+  defaultBufferMinutes: integer("default_buffer_minutes").notNull().default(0),
   createdAt: timestamp("created_at").notNull().defaultNow(),
   updatedAt: timestamp("updated_at").notNull().defaultNow(),
 });
@@ -640,3 +661,34 @@ export const authProviderConfig = pgTable("auth_provider_config", {
   createdAt: timestamp("created_at").notNull().defaultNow(),
   updatedAt: timestamp("updated_at").notNull().defaultNow(),
 });
+
+// ─── Buffer Rules ─────────────────────────────────────────────────────────────
+
+// Buffer time rules per service + pet size/coat combination.
+// Covers service-level defaults and pet-specific overrides.
+export const bufferRules = pgTable(
+  "buffer_rules",
+  {
+    id: uuid("id").primaryKey().defaultRandom(),
+    serviceId: uuid("service_id")
+      .notNull()
+      .references(() => services.id, { onDelete: "cascade" }),
+    // null sizeCategory means "any size" (wildcard)
+    sizeCategory: petSizeCategoryEnum("size_category"),
+    // null coatType means "any coat type" (wildcard)
+    coatType: coatTypeEnum("coat_type"),
+    // minutes to add to the service duration for this size/coat combo
+    bufferMinutes: integer("buffer_minutes").notNull(),
+    createdAt: timestamp("created_at").notNull().defaultNow(),
+    updatedAt: timestamp("updated_at").notNull().defaultNow(),
+  },
+  (t) => [
+    // One rule per unique (service, size, coat) combination
+    unique("uq_buffer_rules_service_size_coat").on(
+      t.serviceId,
+      t.sizeCategory,
+      t.coatType
+    ),
+    index("idx_buffer_rules_service_id").on(t.serviceId),
+  ]
+);