diff --git a/packages/db/src/seed.ts b/packages/db/src/seed.ts
index 3e90a9d..375ffe1 100644
--- a/packages/db/src/seed.ts
+++ b/packages/db/src/seed.ts
@@ -385,78 +385,19 @@ const servicesDef = [
   { id: "b0000001-0000-0000-0000-00000000000a", name: "Sanitary Trim", desc: "Hygienic trim of paw pads, face, and sanitary areas", price: 2500, dur: 20 },
 ];
 
-// ── Known-users-only seed (prod/demo) ───────────────────────────────────────
+// ── UAT staff account seeding (shared between seed paths) ─────────────────────
 
 /**
- * Seeds only the minimal known users for prod/demo environments.
- * Creates: Demo Manager staff + Demo Client + Demo Dog + basic services.
- * Idempotent: skips creation if records already exist.
+ * Seeds or upserts the deterministic UAT staff accounts with numeric OIDC subs
+ * from SEED_UAT_*_OIDC_SUB / SEED_UAT_GROOMER_OIDC_SUBS env vars.
+ *
+ * In the full seed path this must run AFTER random staff are created so the
+ * deterministic upserts land on the correct rows (groomers referenced by the
+ * UAT test-client appointment logic use groomers[0] etc.).
+ *
+ * In seedKnownUsers() this replaces the inline UAT-staff block.
  */
-async function seedKnownUsers() {
-  const url = process.env.DATABASE_URL;
-  if (!url) {
-    console.error("DATABASE_URL is not set");
-    process.exit(1);
-  }
-
-  const client = postgres(url, { max: 5 });
-  const db = drizzle(client, { schema });
-
-  console.log("Seeding known users (prod/demo mode)...\n");
-
-  const KNOWN_STAFF_ID = "00000000-0000-0000-0000-000000000001";
-  const DEMO_CLIENT_ID = "00000000-0000-0000-0000-000000000002";
-  const DEMO_PET_ID = "00000000-0000-0000-0000-000000000003";
-
-  // ── Staff: Demo Manager ──
-  const [existingStaff] = await db
-    .select()
-    .from(schema.staff)
-    .where(eq(schema.staff.email, "demo-manager@groombook.dev"))
-    .limit(1);
-
-  if (existingStaff) {
-    console.log(`✓ Staff '${existingStaff.name}' already exists — skipping`);
-  } else {
-    await db.insert(schema.staff).values({
-      id: KNOWN_STAFF_ID,
-      name: "Demo Manager",
-      email: "demo-manager@groombook.dev",
-      oidcSub: "demo-manager-001",
-      role: "manager",
-      isSuperUser: true,
-      active: true,
-    });
-    console.log("✓ Created staff 'Demo Manager' (oidcSub: demo-manager-001)");
-  }
-
-  // ── Staff: SEED_ADMIN_EMAIL admin ──
-  const adminEmail = process.env.SEED_ADMIN_EMAIL;
-  if (adminEmail) {
-    const adminName = process.env.SEED_ADMIN_NAME ?? "Admin";
-    const ADMIN_STAFF_ID = "00000000-0000-0000-0000-000000000002";
-    const [existingAdmin] = await db
-      .select()
-      .from(schema.staff)
-      .where(eq(schema.staff.email, adminEmail))
-      .limit(1);
-
-    if (existingAdmin) {
-      console.log(`✓ Staff admin '${existingAdmin.name}' already exists — skipping`);
-    } else {
-      await db.insert(schema.staff).values({
-        id: ADMIN_STAFF_ID,
-        name: adminName,
-        email: adminEmail,
-        oidcSub: adminEmail,
-        role: "manager",
-        isSuperUser: true,
-        active: true,
-      });
-      console.log(`✓ Created staff admin '${adminName}' (${adminEmail})`);
-    }
-  }
-
+async function seedUatStaffAccounts(db: ReturnType<typeof drizzle>) {
   // ── Staff: UAT Super User (oidcSub from SEED_UAT_SUPER_OIDC_SUB env var) ──
   const uatSuperOidcSub = process.env.SEED_UAT_SUPER_OIDC_SUB;
   if (uatSuperOidcSub) {
@@ -680,6 +621,84 @@ async function seedKnownUsers() {
       console.log(`✓ Created UAT pet '${pet.name}'`);
     }
   }
+}
+
+// ── Known-users-only seed (prod/demo) ───────────────────────────────────────
+
+/**
+ * Seeds only the minimal known users for prod/demo environments.
+ * Creates: Demo Manager staff + Demo Client + Demo Dog + basic services.
+ * Idempotent: skips creation if records already exist.
+ */
+async function seedKnownUsers() {
+  const url = process.env.DATABASE_URL;
+  if (!url) {
+    console.error("DATABASE_URL is not set");
+    process.exit(1);
+  }
+
+  const client = postgres(url, { max: 5 });
+  const db = drizzle(client, { schema });
+
+  console.log("Seeding known users (prod/demo mode)...\n");
+
+  const KNOWN_STAFF_ID = "00000000-0000-0000-0000-000000000001";
+  const DEMO_CLIENT_ID = "00000000-0000-0000-0000-000000000002";
+  const DEMO_PET_ID = "00000000-0000-0000-0000-000000000003";
+
+  // ── Staff: Demo Manager ──
+  const [existingStaff] = await db
+    .select()
+    .from(schema.staff)
+    .where(eq(schema.staff.email, "demo-manager@groombook.dev"))
+    .limit(1);
+
+  if (existingStaff) {
+    console.log(`✓ Staff '${existingStaff.name}' already exists — skipping`);
+  } else {
+    await db.insert(schema.staff).values({
+      id: KNOWN_STAFF_ID,
+      name: "Demo Manager",
+      email: "demo-manager@groombook.dev",
+      oidcSub: "demo-manager-001",
+      role: "manager",
+      isSuperUser: true,
+      active: true,
+    });
+    console.log("✓ Created staff 'Demo Manager' (oidcSub: demo-manager-001)");
+  }
+
+  // ── Staff: SEED_ADMIN_EMAIL admin ──
+  const adminEmail = process.env.SEED_ADMIN_EMAIL;
+  if (adminEmail) {
+    const adminName = process.env.SEED_ADMIN_NAME ?? "Admin";
+    const ADMIN_STAFF_ID = "00000000-0000-0000-0000-000000000002";
+    const [existingAdmin] = await db
+      .select()
+      .from(schema.staff)
+      .where(eq(schema.staff.email, adminEmail))
+      .limit(1);
+
+    if (existingAdmin) {
+      console.log(`✓ Staff admin '${existingAdmin.name}' already exists — skipping`);
+    } else {
+      await db.insert(schema.staff).values({
+        id: ADMIN_STAFF_ID,
+        name: adminName,
+        email: adminEmail,
+        oidcSub: adminEmail,
+        role: "manager",
+        isSuperUser: true,
+        active: true,
+      });
+      console.log(`✓ Created staff admin '${adminName}' (${adminEmail})`);
+    }
+  }
+
+  // ── UAT staff accounts + Better Auth credentials (shared impl) ──────────────
+  // Extracted into seedUatStaffAccounts() so it runs in both seedKnownUsers()
+  // and the full seed() UAT branch.
+  await seedUatStaffAccounts(db);
 
   // ── Services: idempotent upsert using name as unique key ─────────────────────
   // UNIQUE constraint on services.name (migration 0020) must exist first.
@@ -847,30 +866,10 @@ async function seed() {
     console.log(`✓ Upserted admin staff '${adminName}' (${adminEmail})`);
   }
 
-  // ── UAT Groomer Personas (SEED_UAT_GROOMER_EMAILS + SEED_UAT_GROOMER_NAMES) ──
-  const groomerEmails = process.env.SEED_UAT_GROOMER_EMAILS?.split(",").map((e) => e.trim()).filter(Boolean) ?? [];
-  const groomerNames = process.env.SEED_UAT_GROOMER_NAMES?.split(",").map((n) => n.trim()).filter(Boolean) ?? [];
-  const groomerCount = Math.min(groomerEmails.length, groomerNames.length);
-  for (let i = 0; i < groomerCount; i++) {
-    const email = groomerEmails[i]!;
-    const name = groomerNames[i]!;
-    const staffId = `00000000-0000-0000-0000-${String(5 + i).padStart(12, "0")}`;
-    await db.insert(schema.staff)
-      .values({
-        id: staffId,
-        name,
-        email,
-        oidcSub: email,
-        role: "groomer",
-        isSuperUser: false,
-        active: true,
-      })
-      .onConflictDoUpdate({
-        target: schema.staff.email,
-        set: { id: staffId, name, role: "groomer", isSuperUser: false, active: true },
-      });
-    console.log(`✓ Upserted groomer '${name}' (${email})`);
-  }
+  // ── UAT staff accounts + Better Auth credentials (shared impl) ──────────────
+  // Seeds deterministic UAT staff with numeric OIDC subs and Better Auth credentials.
+  // Must run AFTER random staff are created so upserts land correctly.
+  await seedUatStaffAccounts(db);
 
   // ── Services ──
   // Upsert services using name as unique key. With deterministic IDs in