fix(accounts): test Claude accounts on Sonnet 5.5, then Opus 5.5, by default

backend/internal/handler/admin/account_handler.go

@@ -2911,7 +2911,7 @@ func (h *AccountHandler) accountTestCatalog(ctx context.Context, account *servic
 		}
 
 		var models []geminicli.Model
-		for requestedModel := range mapping {
+		for _, requestedModel := range sortedModelMappingKeys(mapping) {
 			var found bool
 			for _, dm := range geminicli.DefaultModels {
 				if dm.ID == requestedModel {
@@ -2963,14 +2963,8 @@ func (h *AccountHandler) accountTestCatalog(ctx context.Context, account *servic
 			defaultByID[model.ID] = model
 		}
 
-		requestedModels := make([]string, 0, len(mapping))
-		for requestedModel := range mapping {
-			requestedModels = append(requestedModels, requestedModel)
-		}
-		sort.Strings(requestedModels)
-
 		var models []xai.Model
-		for _, requestedModel := range requestedModels {
+		for _, requestedModel := range sortedModelMappingKeys(mapping) {
 			if defaultModel, found := defaultByID[requestedModel]; found {
 				models = append(models, defaultModel)
 				continue
@@ -3000,7 +2994,7 @@ func (h *AccountHandler) accountTestCatalog(ctx context.Context, account *servic
 
 	// Return mapped models (keys of the mapping are the available model IDs)
 	var models []claude.Model
-	for requestedModel := range mapping {
+	for _, requestedModel := range sortedModelMappingKeys(mapping) {
 		// Try to find display info from default models
 		var found bool
 		for _, dm := range claude.DefaultModels {
@@ -3024,6 +3018,18 @@ func (h *AccountHandler) accountTestCatalog(ctx context.Context, account *servic
 	return models, nil
 }
 
+// sortedModelMappingKeys lists a mapping's requested model IDs in a stable
+// order, so test model lists and their automatic default do not depend on map
+// iteration.
+func sortedModelMappingKeys(mapping map[string]string) []string {
+	keys := make([]string, 0, len(mapping))
+	for key := range mapping {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	return keys
+}
+
 // openAIAccountTestModels selects request-side model IDs from this account's
 // saved configuration. Discovery enumerates unrestricted accounts and wildcard
 // candidates; it is not an availability gate for explicitly configured models.

backend/internal/handler/admin/account_test_plan_test.go

@@ -181,3 +181,38 @@ func TestAccountTestModelsCarryReasoningOnEveryPlatform(t *testing.T) {
 	require.Equal(t, []openai.Model{{ID: "friendly", Object: "model", Type: "model", DisplayName: "friendly",
 		ReasoningEfforts: levels, DefaultReasoningEffort: defaultLevel}}, openAIRows)
 }
+
+func TestAccountTestPlanAnthropicDefaultFollowsTestModelPreference(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	plan := func(mapping map[string]any) accountTestPlanView {
+		account := &service.Account{ID: 42, Platform: service.PlatformAnthropic, Type: service.AccountTypeAPIKey,
+			Credentials: map[string]any{"model_mapping": mapping}}
+		h := &AccountHandler{adminService: testPlanAdmin{account: account}}
+		router := gin.New()
+		router.GET("/accounts/:id/models", h.GetAvailableModels)
+		out := httptest.NewRecorder()
+		router.ServeHTTP(out, httptest.NewRequest(http.MethodGet, "/accounts/42/models?view=account-test-plan-v1", nil))
+		require.Equal(t, http.StatusOK, out.Code, out.Body.String())
+		var body struct {
+			Data accountTestPlanView `json:"data"`
+		}
+		require.NoError(t, json.Unmarshal(out.Body.Bytes(), &body))
+		return body.Data
+	}
+
+	// Mapping keys are listed in a stable order, so the fallback default does
+	// not depend on map iteration.
+	withoutSonnet55 := plan(map[string]any{
+		"claude-sonnet-4-5-20250929": "claude-sonnet-4-5-20250929", "claude-opus-5-5": "claude-opus-5-5",
+		"claude-fable-5": "claude-fable-5", "claude-haiku-4-5-20251001": "claude-haiku-4-5-20251001",
+	})
+	require.Equal(t, []string{"claude-fable-5", "claude-haiku-4-5-20251001", "claude-opus-5-5", "claude-sonnet-4-5-20250929"},
+		withoutSonnet55.ModeViews["default"].ModelIDs)
+	require.Equal(t, "claude-opus-5-5", withoutSonnet55.ModeViews["default"].DefaultModelID)
+
+	withSonnet55 := plan(map[string]any{"claude-opus-5-5": "claude-opus-5-5", "claude-sonnet-5-5": "claude-sonnet-5-5"})
+	require.Equal(t, "claude-sonnet-5-5", withSonnet55.ModeViews["default"].DefaultModelID)
+
+	neither := plan(map[string]any{"claude-sonnet-4-6": "claude-sonnet-4-6", "claude-fable-5": "claude-fable-5"})
+	require.Equal(t, "claude-fable-5", neither.ModeViews["default"].DefaultModelID)
+}

backend/internal/pkg/claude/constants.go

@@ -231,8 +231,12 @@ func DefaultModelIDs() []string {
 	return ids
 }
 
-// DefaultTestModel 测试时使用的默认模型
-const DefaultTestModel = "claude-sonnet-4-5-20250929"
+// DefaultTestModel 测试时使用的默认模型：Anthropic 为已弃用的
+// claude-sonnet-4-5-20250929（2026-09-30 弃用，2026-11-30 下线）指定的替代。
+const DefaultTestModel = "claude-sonnet-5-5"
+
+// DefaultTestModelFallback 是账号不提供 DefaultTestModel 时的默认测试模型。
+const DefaultTestModelFallback = "claude-opus-5-5"
 
 // ModelIDOverrides Claude OAuth 请求需要的模型 ID 映射
 var ModelIDOverrides = map[string]string{

backend/internal/service/account_test_model.go

@@ -11,25 +11,31 @@ import (
 )
 
 // PickConnectionTestModel chooses the model of a connection test that does not
-// name one: the platform's upstream default test model when the account serves
-// it, otherwise the first text-chat model of the account's own model list
+// name one: the first of the platform's default test models the account serves,
+// otherwise the first text-chat model of the account's own model list
 // (candidates, in display order) or, without a list, of its model mapping.
 // "" leaves the choice to the platform tester's own default.
 func PickConnectionTestModel(account *Account, candidates ...string) string {
 	if account == nil {
 		return ""
 	}
-	preferred := connectionTestDefaultModel(account)
+	preferred := connectionTestDefaultModels(account)
 	if len(candidates) == 0 {
-		if account.IsModelSupported(preferred) {
-			return preferred
+		for _, model := range preferred {
+			if account.IsModelSupported(model) {
+				return model
+			}
 		}
 		for model := range account.GetModelMapping() {
 			candidates = append(candidates, model)
 		}
 		sort.Strings(candidates)
-	} else if slices.Contains(candidates, preferred) {
-		return preferred
+	} else {
+		for _, model := range preferred {
+			if slices.Contains(candidates, model) {
+				return model
+			}
+		}
 	}
 	for _, model := range candidates {
 		if AccountTestSupportsTextConversation(account, model) {
@@ -39,30 +45,34 @@ func PickConnectionTestModel(account *Account, candidates ...string) string {
 	return ""
 }
 
-// connectionTestDefaultModel mirrors the empty-model default of the platform
-// tester that TestAccountConnection dispatches to.
-func connectionTestDefaultModel(account *Account) string {
+// connectionTestDefaultModels lists, most preferred first, the empty-model
+// defaults of the platform tester that TestAccountConnection dispatches to.
+func connectionTestDefaultModels(account *Account) []string {
 	switch {
 	case account.IsOpenCodeGo():
-		return DefaultOpenCodeGoTestModel
+		return []string{DefaultOpenCodeGoTestModel}
 	case account.IsCNProvider():
 		if account.GetAPIProtocol() == APIProtocolAnthropic {
-			return claude.DefaultTestModel
+			return claudeConnectionTestModels
 		}
-		return openai.DefaultTestModel
+		return []string{openai.DefaultTestModel}
 	case account.IsOpenAI():
-		return openai.DefaultTestModel
+		return []string{openai.DefaultTestModel}
 	case account.IsGemini():
-		return geminicli.DefaultTestModel
+		return []string{geminicli.DefaultTestModel}
 	case account.Platform == PlatformGrok:
-		return grokDefaultResponsesModel
+		return []string{grokDefaultResponsesModel}
 	case account.Platform == PlatformAntigravity:
-		return defaultAntigravityTestModel
+		return []string{defaultAntigravityTestModel}
 	default:
-		return claude.DefaultTestModel
+		return claudeConnectionTestModels
 	}
 }
 
+// claudeConnectionTestModels prefers Anthropic's replacement for the deprecated
+// Sonnet 4.5 test model, then the current Opus.
+var claudeConnectionTestModels = []string{claude.DefaultTestModel, claude.DefaultTestModelFallback}
+
 // AccountTestSupportsTextConversation reports whether a model of the account
 // can answer a text connection test: image, audio, embedding, realtime, speech
 // and review-only models are excluded, before and after the account mapping.

backend/internal/service/account_test_models_test.go

@@ -295,3 +295,14 @@ func TestFetchOpenAIAccountModelsMappingChangesReuseRawCache(t *testing.T) {
 	require.Equal(t, original, after.Body, "projection must not mutate the shared catalog")
 	require.EqualValues(t, 1, calls.Load(), "both mappings must reuse the same discovery cache")
 }
+
+func TestPickConnectionTestModelPrefersClaudeTestModelsInOrder(t *testing.T) {
+	account := &Account{ID: 7, Platform: PlatformAnthropic, Type: AccountTypeAPIKey}
+	require.Equal(t, "claude-sonnet-5-5", PickConnectionTestModel(account, "claude-opus-5-5", "claude-sonnet-5-5"))
+	require.Equal(t, "claude-opus-5-5", PickConnectionTestModel(account, "claude-fable-5", "claude-opus-5-5"))
+	require.Equal(t, "claude-fable-5", PickConnectionTestModel(account, "claude-fable-5", "claude-sonnet-4-6"))
+
+	// Without a displayed list the account's own mapping decides.
+	account.Credentials = map[string]any{"model_mapping": map[string]any{"claude-opus-5-5": "claude-opus-5-5", "claude-fable-5": "claude-fable-5"}}
+	require.Equal(t, "claude-opus-5-5", PickConnectionTestModel(account))
+}