diff --git a/creator-keys/tests/buy_key.rs b/creator-keys/tests/buy_key.rs
index bf894c1..d326d26 100644
--- a/creator-keys/tests/buy_key.rs
+++ b/creator-keys/tests/buy_key.rs
@@ -3,7 +3,7 @@
 mod contract_test_env;
 
 use contract_test_env::{
-    compute_expected_buy_price, register_creator_keys, register_test_creator,
+    capture_snapshot, compute_expected_buy_price, register_creator_keys, register_test_creator,
     set_key_price_for_tests, set_protocol_fee_bps, test_env_with_auths,
 };
 use creator_keys::ContractError;
@@ -52,6 +52,32 @@ fn test_buy_key_insufficient_payment_fails() {
     assert_eq!(result, Err(Ok(ContractError::InsufficientPayment)));
 }
 
+#[test]
+fn test_buy_key_unregistered_creator_no_state_mutation() {
+    let env = test_env_with_auths();
+    let (client, _) = register_creator_keys(&env);
+    let base_price = 100i128;
+    set_key_price_for_tests(&env, &client, base_price);
+    set_protocol_fee_bps(&env, &client, 9000u32, 1000u32);
+
+    let registered = register_test_creator(&env, &client, "alice");
+    let buyer = Address::generate(&env);
+    client.buy_key(&registered, &buyer, &base_price, &None);
+
+    let snapshot_before = capture_snapshot(&client, &registered, &buyer);
+
+    let unregistered = Address::generate(&env);
+    let result = client.try_buy_key(&unregistered, &buyer, &base_price, &None);
+    assert_eq!(result, Err(Ok(ContractError::NotRegistered)));
+
+    let snapshot_after = capture_snapshot(&client, &registered, &buyer);
+    snapshot_before.assert_unchanged(&snapshot_after);
+
+    assert_eq!(client.get_total_key_supply(&unregistered), 0);
+    assert_eq!(client.get_key_balance(&unregistered, &buyer), 0);
+    assert_eq!(client.get_creator_holder_count(&unregistered), 0);
+}
+
 #[test]
 fn test_buy_key_sufficient_payment_succeeds() {
     let env = test_env_with_auths();
diff --git a/creator-keys/tests/key_supply.rs b/creator-keys/tests/key_supply.rs
index 471393b..7af0181 100644
--- a/creator-keys/tests/key_supply.rs
+++ b/creator-keys/tests/key_supply.rs
@@ -67,6 +67,36 @@ fn test_get_total_key_supply_increments_after_buy() {
     assert_eq!(client.get_total_key_supply(&creator), 2);
 }
 
+#[test]
+fn test_get_total_key_supply_increments_after_three_sequential_buys() {
+    let env = Env::default();
+    env.mock_all_auths();
+    let (client, _) = setup(&env);
+
+    let creator = Address::generate(&env);
+    let buyer1 = Address::generate(&env);
+    let buyer2 = Address::generate(&env);
+    let buyer3 = Address::generate(&env);
+    client.register_creator(
+        &creator,
+        &String::from_str(&env, "alice"),
+        &None,
+        &None,
+        &None,
+    );
+
+    assert_eq!(client.get_total_key_supply(&creator), 0);
+
+    client.buy_key(&creator, &buyer1, &100_i128, &None);
+    assert_eq!(client.get_total_key_supply(&creator), 1);
+
+    client.buy_key(&creator, &buyer2, &100_i128, &None);
+    assert_eq!(client.get_total_key_supply(&creator), 2);
+
+    client.buy_key(&creator, &buyer3, &100_i128, &None);
+    assert_eq!(client.get_total_key_supply(&creator), 3);
+}
+
 #[test]
 fn test_get_total_key_supply_is_read_only() {
     let env = Env::default();