diff --git a/README.md b/README.md
index eedf7a8..29d62a4 100644
--- a/README.md
+++ b/README.md
@@ -376,11 +376,14 @@ Allows test code to dynamically configure the responses returned by the OAuth2 e
   "error_scenario": {
     "endpoint": "token", 
     "error": "invalid_grant",
-    "error_description": "Custom error for testing"
+    "error_description": "Custom error for testing",
+    "enabled": true
   }
 }
 ```
 
+**Note**: The `enabled` field is optional and defaults to `true` when `endpoint` and `error` are provided. To explicitly disable an error scenario, set `"enabled": false`.
+
 **Response**:
 
 ```json
@@ -392,6 +395,30 @@ Allows test code to dynamically configure the responses returned by the OAuth2 e
 
 **IMPORTANT**: To update user information that will be returned by the `/userinfo` endpoint, you must include the user profile data inside the `tokens.user_info` object, not in the top-level `user_info` field. The top-level `user_info` field updates a different user object that is not used by the `/userinfo` endpoint.
 
+**Error Scenario Configuration**:
+
+The `error_scenario` object supports the following OAuth2 error codes for testing:
+
+**Authorize endpoint errors:**
+- `access_denied` - User denied access
+- `unauthorized_client` - Client not authorized for this grant type
+- `invalid_scope` - Requested scope is invalid or unknown
+- `temporarily_unavailable` - Server is temporarily unavailable
+- `invalid_request` - Request is missing a required parameter or malformed
+- `unsupported_response_type` - Response type is not supported
+- `server_error` - Internal server error occurred
+
+**Token endpoint errors:**
+- `invalid_grant` - Invalid authorization code or credentials
+- `invalid_client` - Client authentication failed
+- `unsupported_grant_type` - Grant type is not supported
+- `invalid_request` - Request is malformed
+
+**Userinfo endpoint errors:**
+- `invalid_token` - Access token is invalid or expired
+- `insufficient_scope` - Token lacks required scope
+- `server_error` - Internal server error occurred
+
 This enables testing scenarios like:
 
 - Testing how your application handles different user profiles
diff --git a/internal/handlers/config.go b/internal/handlers/config.go
index 88dc82b..59fb74c 100644
--- a/internal/handlers/config.go
+++ b/internal/handlers/config.go
@@ -34,9 +34,9 @@ type ConfigRequest struct {
 
 // ErrorScenario defines an error condition to simulate
 type ErrorScenario struct {
-	Enabled          bool   `json:"enabled"`  // Whether the error scenario is enabled
-	Endpoint         string `json:"endpoint"` // Which endpoint should return an error (authorize, token, userinfo)
-	Error            string `json:"error"`    // OAuth2 error code
+	Enabled          *bool  `json:"enabled,omitempty"` // Whether the error scenario is enabled (defaults to true if not specified)
+	Endpoint         string `json:"endpoint"`          // Which endpoint should return an error (authorize, token, userinfo)
+	Error            string `json:"error"`             // OAuth2 error code
 	ErrorDescription string `json:"error_description,omitempty"`
 }
 
@@ -109,9 +109,17 @@ func (h *ConfigHandler) storeTokenConfig(tokenConfig map[string]interface{}) {
 
 // storeErrorScenario saves error scenario configuration to the store
 func (h *ConfigHandler) storeErrorScenario(scenario ErrorScenario) {
+	// Default enabled to true when an error scenario is being configured
+	// If Enabled is nil (not provided), default to true
+	// If Enabled is explicitly set (true or false), use that value
+	enabled := true
+	if scenario.Enabled != nil {
+		enabled = *scenario.Enabled
+	}
+
 	// Convert from handlers.ErrorScenario to types.ErrorScenario
 	storeScenario := types.ErrorScenario{
-		Enabled:     scenario.Enabled,
+		Enabled:     enabled,
 		Endpoint:    scenario.Endpoint,
 		StatusCode:  determineStatusCode(scenario.Error),
 		ErrorCode:   scenario.Error,
diff --git a/internal/handlers/config_test.go b/internal/handlers/config_test.go
index d94979e..6a37971 100644
--- a/internal/handlers/config_test.go
+++ b/internal/handlers/config_test.go
@@ -28,6 +28,11 @@ func newMockStore() *mockStore {
 	}
 }
 
+// Helper function to create a bool pointer
+func boolPtr(b bool) *bool {
+	return &b
+}
+
 func (s *mockStore) StoreAuthCode(code string, request *models.AuthRequest) {
 	s.authCodes[code] = request
 }
@@ -255,7 +260,7 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 		{
 			name: "invalid_request",
 			errorScenario: ErrorScenario{
-				Enabled:          true,
+				Enabled:          boolPtr(true),
 				Endpoint:         "token",
 				Error:            "invalid_request",
 				ErrorDescription: "Test invalid request",
@@ -265,7 +270,7 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 		{
 			name: "invalid_client",
 			errorScenario: ErrorScenario{
-				Enabled:          true,
+				Enabled:          boolPtr(true),
 				Endpoint:         "token",
 				Error:            "invalid_client",
 				ErrorDescription: "Test invalid client",
@@ -275,7 +280,7 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 		{
 			name: "server_error",
 			errorScenario: ErrorScenario{
-				Enabled:          true,
+				Enabled:          boolPtr(true),
 				Endpoint:         "userinfo",
 				Error:            "server_error",
 				ErrorDescription: "Test server error",
@@ -285,7 +290,7 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 		{
 			name: "unknown_error",
 			errorScenario: ErrorScenario{
-				Enabled:          true,
+				Enabled:          boolPtr(true),
 				Endpoint:         "authorize",
 				Error:            "unknown_error",
 				ErrorDescription: "Test unknown error",
@@ -295,7 +300,7 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 		{
 			name: "unsupported_response_type",
 			errorScenario: ErrorScenario{
-				Enabled:          true,
+				Enabled:          boolPtr(true),
 				Endpoint:         "authorize",
 				Error:            "unsupported_response_type",
 				ErrorDescription: "Response type not supported",
@@ -305,7 +310,7 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 		{
 			name: "temporarily_unavailable",
 			errorScenario: ErrorScenario{
-				Enabled:          true,
+				Enabled:          boolPtr(true),
 				Endpoint:         "authorize",
 				Error:            "temporarily_unavailable",
 				ErrorDescription: "Server is under maintenance",
@@ -340,8 +345,9 @@ func TestConfigHandler_UpdateErrorScenario(t *testing.T) {
 			}
 
 			// Check the fields were stored correctly
-			if scenario.Enabled != tc.errorScenario.Enabled {
-				t.Errorf("wrong enabled status stored: got %v want %v", scenario.Enabled, tc.errorScenario.Enabled)
+			expectedEnabled := tc.errorScenario.Enabled != nil && *tc.errorScenario.Enabled
+			if scenario.Enabled != expectedEnabled {
+				t.Errorf("wrong enabled status stored: got %v want %v", scenario.Enabled, expectedEnabled)
 			}
 			if scenario.Endpoint != tc.errorScenario.Endpoint {
 				t.Errorf("wrong endpoint stored: got %v want %v", scenario.Endpoint, tc.errorScenario.Endpoint)
@@ -376,7 +382,7 @@ func TestConfigHandler_CombinedUpdate(t *testing.T) {
 			"expires_in":   2400,
 		},
 		ErrorScenario: &ErrorScenario{
-			Enabled:          true,
+			Enabled:          boolPtr(true),
 			Endpoint:         "token",
 			Error:            "invalid_grant",
 			ErrorDescription: "Combined test error",
@@ -476,3 +482,80 @@ func TestDetermineStatusCode(t *testing.T) {
 		})
 	}
 }
+
+func TestConfigHandler_ErrorScenarioDefaultEnabled(t *testing.T) {
+	// Setup
+	mockStore := newMockStore()
+	defaultUser := models.NewDefaultUser()
+	handler := NewConfigHandler(mockStore, defaultUser)
+
+	// Test case where enabled field is not set (nil pointer)
+	// Should default to true when endpoint and error are provided
+	configReq := ConfigRequest{
+		ErrorScenario: &ErrorScenario{
+			// Enabled field not set (nil), will default to true
+			Endpoint:         "authorize",
+			Error:            "unauthorized_client",
+			ErrorDescription: "Client not authorized",
+		},
+	}
+	reqBody, _ := json.Marshal(configReq)
+	req := httptest.NewRequest("POST", "/config", bytes.NewBuffer(reqBody))
+	rr := httptest.NewRecorder()
+
+	// Call handler
+	handler.ServeHTTP(rr, req)
+
+	// Check response code
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusOK)
+	}
+
+	// Verify error scenario was stored and ENABLED by default
+	scenario, exists := mockStore.GetErrorScenario("authorize")
+	if !exists {
+		t.Errorf("error scenario not found for authorize endpoint")
+		return
+	}
+
+	if !scenario.Enabled {
+		t.Errorf("error scenario should be enabled by default when endpoint and error are provided, got enabled=%v", scenario.Enabled)
+	}
+	if scenario.ErrorCode != "unauthorized_client" {
+		t.Errorf("wrong error code stored: got %v want %v", scenario.ErrorCode, "unauthorized_client")
+	}
+}
+
+func TestConfigHandler_ErrorScenarioExplicitlyDisabled(t *testing.T) {
+	// Setup
+	mockStore := newMockStore()
+	defaultUser := models.NewDefaultUser()
+	handler := NewConfigHandler(mockStore, defaultUser)
+
+	// Test case where enabled is explicitly set to false
+	configReq := ConfigRequest{
+		ErrorScenario: &ErrorScenario{
+			Enabled:          boolPtr(false), // Explicitly disabled
+			Endpoint:         "authorize",
+			Error:            "access_denied",
+			ErrorDescription: "Should not be active",
+		},
+	}
+	reqBody, _ := json.Marshal(configReq)
+	req := httptest.NewRequest("POST", "/config", bytes.NewBuffer(reqBody))
+	rr := httptest.NewRecorder()
+
+	// Call handler
+	handler.ServeHTTP(rr, req)
+
+	// Check response code
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v", status, http.StatusOK)
+	}
+
+	// Verify error scenario is stored but NOT enabled
+	scenario, exists := mockStore.GetErrorScenario("authorize")
+	if exists {
+		t.Errorf("error scenario should not be returned when disabled, but got: %+v", scenario)
+	}
+}