diff --git a/backend/internal/handler/gateway_handler.go b/backend/internal/handler/gateway_handler.go
index b65dedf9cc..b20d9ef652 100644
--- a/backend/internal/handler/gateway_handler.go
+++ b/backend/internal/handler/gateway_handler.go
@@ -1006,7 +1006,8 @@ func (h *GatewayHandler) Models(c *gin.Context) {
 	// Get available models from account configurations for the selected group platform.
 	availableModels := h.gatewayService.GetAvailableModels(c.Request.Context(), groupID, platform)
 	if apiKey != nil && apiKey.Group != nil && apiKey.Group.CustomModelsListEnabled() {
-		availableModels = filterModelsByCustomList(availableModels, defaultModelIDsForPlatform(platform), apiKey.Group.ModelsListConfig.Models)
+		fallbackModels := defaultModelIDsForPlatform(platform)
+		availableModels = filterModelsByCustomList(customModelsListSource(platform, availableModels, fallbackModels), fallbackModels, apiKey.Group.ModelsListConfig.Models)
 		writeCustomModelsList(c, platform, availableModels)
 		return
 	}
@@ -1090,6 +1091,13 @@ func writeOpenAIModelsList(c *gin.Context, modelIDs []string) {
 	})
 }
 
+func customModelsListSource(platform string, availableModels, fallbackModels []string) []string {
+	if platform == service.PlatformAnthropic && len(availableModels) > 0 {
+		return mergeModelIDs(availableModels, fallbackModels)
+	}
+	return availableModels
+}
+
 func filterModelsByCustomList(availableModels, fallbackModels, selectedModels []string) []string {
 	if len(selectedModels) == 0 {
 		return availableModels
@@ -1158,6 +1166,15 @@ func defaultModelIDsForPlatform(platform string) []string {
 			ids = append(ids, model.ID)
 		}
 		return ids
+	case service.PlatformAnthropic:
+		ids := make([]string, 0, len(claude.DefaultModels)+len(antigravity.DefaultModels()))
+		for _, model := range claude.DefaultModels {
+			ids = append(ids, model.ID)
+		}
+		for _, model := range antigravity.DefaultModels() {
+			ids = append(ids, model.ID)
+		}
+		return mergeModelIDs(ids, nil)
 	case service.PlatformGrok:
 		return xai.DefaultModelIDs()
 	default:
@@ -1169,6 +1186,25 @@ func defaultModelIDsForPlatform(platform string) []string {
 	}
 }
 
+func mergeModelIDs(primary, secondary []string) []string {
+	seen := make(map[string]struct{}, len(primary)+len(secondary))
+	merged := make([]string, 0, len(primary)+len(secondary))
+	for _, models := range [][]string{primary, secondary} {
+		for _, model := range models {
+			model = strings.TrimSpace(model)
+			if model == "" {
+				continue
+			}
+			if _, ok := seen[model]; ok {
+				continue
+			}
+			seen[model] = struct{}{}
+			merged = append(merged, model)
+		}
+	}
+	return merged
+}
+
 // AntigravityModels 返回 Antigravity 支持的全部模型
 // GET /antigravity/models
 func (h *GatewayHandler) AntigravityModels(c *gin.Context) {
diff --git a/backend/internal/handler/gateway_models_test.go b/backend/internal/handler/gateway_models_test.go
index c5238f2a2f..6011e13027 100644
--- a/backend/internal/handler/gateway_models_test.go
+++ b/backend/internal/handler/gateway_models_test.go
@@ -269,6 +269,149 @@ func TestGatewayModels_CustomModelsListKeepsConcreteModelAllowedByWildcardMappin
 	require.Equal(t, []string{"claude-sonnet-4-6"}, modelIDsForTest(got.Data))
 }
 
+func TestGatewayModels_AnthropicCustomModelsListIncludesOAuthClaudeAndMappedDeepSeek(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	groupID := int64(28)
+	h := newGatewayModelsHandlerForTest(
+		&gatewayModelsAccountRepoStub{
+			byGroup: map[int64][]service.Account{
+				groupID: {
+					{
+						ID:       1,
+						Platform: service.PlatformAnthropic,
+						Type:     service.AccountTypeOAuth,
+					},
+					{
+						ID:       2,
+						Platform: service.PlatformAnthropic,
+						Type:     service.AccountTypeAPIKey,
+						Credentials: map[string]any{
+							"model_mapping": map[string]any{
+								"deepseek-v4-pro": "deepseek-v4-pro",
+							},
+						},
+					},
+				},
+			},
+		},
+	)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodGet, "/v1/models", nil)
+	c.Set(string(middleware2.ContextKeyAPIKey), &service.APIKey{
+		Group: &service.Group{
+			ID:       groupID,
+			Platform: service.PlatformAnthropic,
+			ModelsListConfig: service.GroupModelsListConfig{
+				Enabled: true,
+				Models:  []string{"claude-fable-5", "claude-opus-4-8", "deepseek-v4-pro"},
+			},
+		},
+	})
+
+	h.Models(c)
+
+	require.Equal(t, http.StatusOK, rec.Code)
+
+	var got gatewayModelsResponseForTest
+	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &got))
+	require.Equal(t, []string{"claude-fable-5", "claude-opus-4-8", "deepseek-v4-pro"}, modelIDsForTest(got.Data))
+}
+
+func TestGatewayModels_AnthropicCustomModelsListDisabledKeepsMappedModelList(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	groupID := int64(29)
+	h := newGatewayModelsHandlerForTest(
+		&gatewayModelsAccountRepoStub{
+			byGroup: map[int64][]service.Account{
+				groupID: {
+					{
+						ID:       1,
+						Platform: service.PlatformAnthropic,
+						Type:     service.AccountTypeOAuth,
+					},
+					{
+						ID:       2,
+						Platform: service.PlatformAnthropic,
+						Type:     service.AccountTypeAPIKey,
+						Credentials: map[string]any{
+							"model_mapping": map[string]any{
+								"deepseek-v4-pro": "deepseek-v4-pro",
+							},
+						},
+					},
+				},
+			},
+		},
+	)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodGet, "/v1/models", nil)
+	c.Set(string(middleware2.ContextKeyAPIKey), &service.APIKey{
+		Group: &service.Group{
+			ID:       groupID,
+			Platform: service.PlatformAnthropic,
+			ModelsListConfig: service.GroupModelsListConfig{
+				Enabled: false,
+				Models:  []string{"claude-fable-5", "deepseek-v4-pro"},
+			},
+		},
+	})
+
+	h.Models(c)
+
+	require.Equal(t, http.StatusOK, rec.Code)
+
+	var got gatewayModelsResponseForTest
+	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &got))
+	require.Equal(t, []string{"deepseek-v4-pro"}, modelIDsForTest(got.Data))
+}
+
+func TestGatewayModels_AnthropicCustomModelsListIncludesOAuthClaudeWithoutMappings(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	groupID := int64(30)
+	h := newGatewayModelsHandlerForTest(
+		&gatewayModelsAccountRepoStub{
+			byGroup: map[int64][]service.Account{
+				groupID: {
+					{
+						ID:       1,
+						Platform: service.PlatformAnthropic,
+						Type:     service.AccountTypeOAuth,
+					},
+				},
+			},
+		},
+	)
+
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodGet, "/v1/models", nil)
+	c.Set(string(middleware2.ContextKeyAPIKey), &service.APIKey{
+		Group: &service.Group{
+			ID:       groupID,
+			Platform: service.PlatformAnthropic,
+			ModelsListConfig: service.GroupModelsListConfig{
+				Enabled: true,
+				Models:  []string{"claude-opus-4-6-thinking", "claude-sonnet-4-5"},
+			},
+		},
+	})
+
+	h.Models(c)
+
+	require.Equal(t, http.StatusOK, rec.Code)
+
+	var got gatewayModelsResponseForTest
+	require.NoError(t, json.Unmarshal(rec.Body.Bytes(), &got))
+	require.Equal(t, []string{"claude-opus-4-6-thinking", "claude-sonnet-4-5"}, modelIDsForTest(got.Data))
+}
+
 func TestGatewayModels_CustomModelsListCanReturnEmptyWhenSelectionsUnavailable(t *testing.T) {
 	gin.SetMode(gin.TestMode)