diff --git a/apps/api/src/db/seed.ts b/apps/api/src/db/seed.ts
index 058b7c9..77f6709 100644
--- a/apps/api/src/db/seed.ts
+++ b/apps/api/src/db/seed.ts
@@ -459,6 +459,32 @@ async function seedKnownUsers() {
     }
   }
 
+  // ── Staff: UAT Tester (oidcSub from SEED_UAT_TESTER_OIDC_SUB env var) ──
+  const uatTesterOidcSub = process.env.SEED_UAT_TESTER_OIDC_SUB;
+  if (uatTesterOidcSub) {
+    const UAT_TESTER_STAFF_ID = "00000000-0000-0000-0000-000000000007";
+    const [existingUatTester] = await db
+      .select()
+      .from(schema.staff)
+      .where(eq(schema.staff.email, "uat-tester@groombook.dev"))
+      .limit(1);
+
+    if (existingUatTester) {
+      console.log(`✓ Staff 'UAT Tester' already exists — skipping`);
+    } else {
+      await db.insert(schema.staff).values({
+        id: UAT_TESTER_STAFF_ID,
+        name: "UAT Tester",
+        email: "uat-tester@groombook.dev",
+        oidcSub: uatTesterOidcSub,
+        role: "groomer",
+        isSuperUser: false,
+        active: true,
+      });
+      console.log(`✓ Created staff 'UAT Tester' (oidcSub: ${uatTesterOidcSub})`);
+    }
+  }
+
   // ── Staff: 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) ?? [];