Merge pull request #1922 from shenshuoyaoyouguang/pr/model-registry-safety

fix(registry): clone model snapshots and invalidate available-model cache

internal/registry/model_registry.go

@@ -62,6 +62,11 @@ type ModelInfo struct {
 	UserDefined bool `json:"-"`
 }
 
+type availableModelsCacheEntry struct {
+	models    []map[string]any
+	expiresAt time.Time
+}
+
 // ThinkingSupport describes a model family's supported internal reasoning budget range.
 // Values are interpreted in provider-native token units.
 type ThinkingSupport struct {
@@ -116,6 +121,8 @@ type ModelRegistry struct {
 	clientProviders map[string]string
 	// mutex ensures thread-safe access to the registry
 	mutex *sync.RWMutex
+	// availableModelsCache stores per-handler snapshots for GetAvailableModels.
+	availableModelsCache map[string]availableModelsCacheEntry
 	// hook is an optional callback sink for model registration changes
 	hook ModelRegistryHook
 }
@@ -132,11 +139,24 @@ func GetGlobalRegistry() *ModelRegistry {
 			clientModels:         make(map[string][]string),
 			clientModelInfos:     make(map[string]map[string]*ModelInfo),
 			clientProviders:      make(map[string]string),
+			availableModelsCache: make(map[string]availableModelsCacheEntry),
 			mutex:                &sync.RWMutex{},
 		}
 	})
 	return globalRegistry
 }
+func (r *ModelRegistry) ensureAvailableModelsCacheLocked() {
+	if r.availableModelsCache == nil {
+		r.availableModelsCache = make(map[string]availableModelsCacheEntry)
+	}
+}
+
+func (r *ModelRegistry) invalidateAvailableModelsCacheLocked() {
+	if len(r.availableModelsCache) == 0 {
+		return
+	}
+	clear(r.availableModelsCache)
+}
 
 // LookupModelInfo searches dynamic registry (provider-specific > global) then static definitions.
 func LookupModelInfo(modelID string, provider ...string) *ModelInfo {
@@ -151,9 +171,9 @@ func LookupModelInfo(modelID string, provider ...string) *ModelInfo {
 	}
 
 	if info := GetGlobalRegistry().GetModelInfo(modelID, p); info != nil {
-		return info
+		return cloneModelInfo(info)
 	}
-	return LookupStaticModelInfo(modelID)
+	return cloneModelInfo(LookupStaticModelInfo(modelID))
 }
 
 // SetHook sets an optional hook for observing model registration changes.
@@ -211,6 +231,7 @@ func (r *ModelRegistry) triggerModelsUnregistered(provider, clientID string) {
 func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models []*ModelInfo) {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
+	r.ensureAvailableModelsCacheLocked()
 
 	provider := strings.ToLower(clientProvider)
 	uniqueModelIDs := make([]string, 0, len(models))
@@ -236,6 +257,7 @@ func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models [
 		delete(r.clientModels, clientID)
 		delete(r.clientModelInfos, clientID)
 		delete(r.clientProviders, clientID)
+		r.invalidateAvailableModelsCacheLocked()
 		misc.LogCredentialSeparator()
 		return
 	}
@@ -263,6 +285,7 @@ func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models [
 		} else {
 			delete(r.clientProviders, clientID)
 		}
+		r.invalidateAvailableModelsCacheLocked()
 		r.triggerModelsRegistered(provider, clientID, models)
 		log.Debugf("Registered client %s from provider %s with %d models", clientID, clientProvider, len(rawModelIDs))
 		misc.LogCredentialSeparator()
@@ -406,6 +429,7 @@ func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models [
 		delete(r.clientProviders, clientID)
 	}
 
+	r.invalidateAvailableModelsCacheLocked()
 	r.triggerModelsRegistered(provider, clientID, models)
 	if len(added) == 0 && len(removed) == 0 && !providerChanged {
 		// Only metadata (e.g., display name) changed; skip separator when no log output.
@@ -509,6 +533,13 @@ func cloneModelInfo(model *ModelInfo) *ModelInfo {
 	if len(model.SupportedOutputModalities) > 0 {
 		copyModel.SupportedOutputModalities = append([]string(nil), model.SupportedOutputModalities...)
 	}
+	if model.Thinking != nil {
+		copyThinking := *model.Thinking
+		if len(model.Thinking.Levels) > 0 {
+			copyThinking.Levels = append([]string(nil), model.Thinking.Levels...)
+		}
+		copyModel.Thinking = &copyThinking
+	}
 	return &copyModel
 }
 
@@ -538,6 +569,7 @@ func (r *ModelRegistry) UnregisterClient(clientID string) {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
 	r.unregisterClientInternal(clientID)
+	r.invalidateAvailableModelsCacheLocked()
 }
 
 // unregisterClientInternal performs the actual client unregistration (internal, no locking)
@@ -604,9 +636,12 @@ func (r *ModelRegistry) unregisterClientInternal(clientID string) {
 func (r *ModelRegistry) SetModelQuotaExceeded(clientID, modelID string) {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
+	r.ensureAvailableModelsCacheLocked()
 
 	if registration, exists := r.models[modelID]; exists {
-		registration.QuotaExceededClients[clientID] = new(time.Now())
+		now := time.Now()
+		registration.QuotaExceededClients[clientID] = &now
+		r.invalidateAvailableModelsCacheLocked()
 		log.Debugf("Marked model %s as quota exceeded for client %s", modelID, clientID)
 	}
 }
@@ -618,9 +653,11 @@ func (r *ModelRegistry) SetModelQuotaExceeded(clientID, modelID string) {
 func (r *ModelRegistry) ClearModelQuotaExceeded(clientID, modelID string) {
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
+	r.ensureAvailableModelsCacheLocked()
 
 	if registration, exists := r.models[modelID]; exists {
 		delete(registration.QuotaExceededClients, clientID)
+		r.invalidateAvailableModelsCacheLocked()
 		// log.Debugf("Cleared quota exceeded status for model %s and client %s", modelID, clientID)
 	}
 }
@@ -636,6 +673,7 @@ func (r *ModelRegistry) SuspendClientModel(clientID, modelID, reason string) {
 	}
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
+	r.ensureAvailableModelsCacheLocked()
 
 	registration, exists := r.models[modelID]
 	if !exists || registration == nil {
@@ -649,6 +687,7 @@ func (r *ModelRegistry) SuspendClientModel(clientID, modelID, reason string) {
 	}
 	registration.SuspendedClients[clientID] = reason
 	registration.LastUpdated = time.Now()
+	r.invalidateAvailableModelsCacheLocked()
 	if reason != "" {
 		log.Debugf("Suspended client %s for model %s: %s", clientID, modelID, reason)
 	} else {
@@ -666,6 +705,7 @@ func (r *ModelRegistry) ResumeClientModel(clientID, modelID string) {
 	}
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
+	r.ensureAvailableModelsCacheLocked()
 
 	registration, exists := r.models[modelID]
 	if !exists || registration == nil || registration.SuspendedClients == nil {
@@ -676,6 +716,7 @@ func (r *ModelRegistry) ResumeClientModel(clientID, modelID string) {
 	}
 	delete(registration.SuspendedClients, clientID)
 	registration.LastUpdated = time.Now()
+	r.invalidateAvailableModelsCacheLocked()
 	log.Debugf("Resumed client %s for model %s", clientID, modelID)
 }
 
@@ -711,22 +752,52 @@ func (r *ModelRegistry) ClientSupportsModel(clientID, modelID string) bool {
 // Returns:
 //   - []map[string]any: List of available models in the requested format
 func (r *ModelRegistry) GetAvailableModels(handlerType string) []map[string]any {
-	r.mutex.RLock()
-	defer r.mutex.RUnlock()
-
-	models := make([]map[string]any, 0)
-	quotaExpiredDuration := 5 * time.Minute
-
-	for _, registration := range r.models {
-		// Check if model has any non-quota-exceeded clients
-		availableClients := registration.Count
 	now := time.Now()
 
-		// Count clients that have exceeded quota but haven't recovered yet
+	r.mutex.RLock()
+	if cache, ok := r.availableModelsCache[handlerType]; ok && (cache.expiresAt.IsZero() || now.Before(cache.expiresAt)) {
+		models := cloneModelMaps(cache.models)
+		r.mutex.RUnlock()
+		return models
+	}
+	r.mutex.RUnlock()
+
+	r.mutex.Lock()
+	defer r.mutex.Unlock()
+	r.ensureAvailableModelsCacheLocked()
+
+	if cache, ok := r.availableModelsCache[handlerType]; ok && (cache.expiresAt.IsZero() || now.Before(cache.expiresAt)) {
+		return cloneModelMaps(cache.models)
+	}
+
+	models, expiresAt := r.buildAvailableModelsLocked(handlerType, now)
+	r.availableModelsCache[handlerType] = availableModelsCacheEntry{
+		models:    cloneModelMaps(models),
+		expiresAt: expiresAt,
+	}
+
+	return models
+}
+
+func (r *ModelRegistry) buildAvailableModelsLocked(handlerType string, now time.Time) ([]map[string]any, time.Time) {
+	models := make([]map[string]any, 0, len(r.models))
+	quotaExpiredDuration := 5 * time.Minute
+	var expiresAt time.Time
+
+	for _, registration := range r.models {
+		availableClients := registration.Count
+
 		expiredClients := 0
 		for _, quotaTime := range registration.QuotaExceededClients {
-			if quotaTime != nil && now.Sub(*quotaTime) < quotaExpiredDuration {
+			if quotaTime == nil {
+				continue
+			}
+			recoveryAt := quotaTime.Add(quotaExpiredDuration)
+			if now.Before(recoveryAt) {
 				expiredClients++
+				if expiresAt.IsZero() || recoveryAt.Before(expiresAt) {
+					expiresAt = recoveryAt
+				}
 			}
 		}
 
@@ -747,7 +818,6 @@ func (r *ModelRegistry) GetAvailableModels(handlerType string) []map[string]any
 			effectiveClients = 0
 		}
 
-		// Include models that have available clients, or those solely cooling down.
 		if effectiveClients > 0 || (availableClients > 0 && (expiredClients > 0 || cooldownSuspended > 0) && otherSuspended == 0) {
 			model := r.convertModelToMap(registration.Info, handlerType)
 			if model != nil {
@@ -756,7 +826,44 @@ func (r *ModelRegistry) GetAvailableModels(handlerType string) []map[string]any
 		}
 	}
 
-	return models
+	return models, expiresAt
+}
+
+func cloneModelMaps(models []map[string]any) []map[string]any {
+	cloned := make([]map[string]any, 0, len(models))
+	for _, model := range models {
+		if model == nil {
+			cloned = append(cloned, nil)
+			continue
+		}
+		copyModel := make(map[string]any, len(model))
+		for key, value := range model {
+			copyModel[key] = cloneModelMapValue(value)
+		}
+		cloned = append(cloned, copyModel)
+	}
+	return cloned
+}
+
+func cloneModelMapValue(value any) any {
+	switch typed := value.(type) {
+	case map[string]any:
+		copyMap := make(map[string]any, len(typed))
+		for key, entry := range typed {
+			copyMap[key] = cloneModelMapValue(entry)
+		}
+		return copyMap
+	case []any:
+		copySlice := make([]any, len(typed))
+		for i, entry := range typed {
+			copySlice[i] = cloneModelMapValue(entry)
+		}
+		return copySlice
+	case []string:
+		return append([]string(nil), typed...)
+	default:
+		return value
+	}
 }
 
 // GetAvailableModelsByProvider returns models available for the given provider identifier.
@@ -872,11 +979,11 @@ func (r *ModelRegistry) GetAvailableModelsByProvider(provider string) []*ModelIn
 
 		if effectiveClients > 0 || (availableClients > 0 && (expiredClients > 0 || cooldownSuspended > 0) && otherSuspended == 0) {
 			if entry.info != nil {
-				result = append(result, entry.info)
+				result = append(result, cloneModelInfo(entry.info))
 				continue
 			}
 			if ok && registration != nil && registration.Info != nil {
-				result = append(result, registration.Info)
+				result = append(result, cloneModelInfo(registration.Info))
 			}
 		}
 	}
@@ -985,13 +1092,13 @@ func (r *ModelRegistry) GetModelInfo(modelID, provider string) *ModelInfo {
 			if reg.Providers != nil {
 				if count, ok := reg.Providers[provider]; ok && count > 0 {
 					if info, ok := reg.InfoByProvider[provider]; ok && info != nil {
-						return info
+						return cloneModelInfo(info)
 					}
 				}
 			}
 		}
 		// Fallback to global info (last registered)
-		return reg.Info
+		return cloneModelInfo(reg.Info)
 	}
 	return nil
 }
@@ -1031,7 +1138,7 @@ func (r *ModelRegistry) convertModelToMap(model *ModelInfo, handlerType string)
 			result["max_completion_tokens"] = model.MaxCompletionTokens
 		}
 		if len(model.SupportedParameters) > 0 {
-			result["supported_parameters"] = model.SupportedParameters
+			result["supported_parameters"] = append([]string(nil), model.SupportedParameters...)
 		}
 		return result
 
@@ -1075,13 +1182,13 @@ func (r *ModelRegistry) convertModelToMap(model *ModelInfo, handlerType string)
 			result["outputTokenLimit"] = model.OutputTokenLimit
 		}
 		if len(model.SupportedGenerationMethods) > 0 {
-			result["supportedGenerationMethods"] = model.SupportedGenerationMethods
+			result["supportedGenerationMethods"] = append([]string(nil), model.SupportedGenerationMethods...)
 		}
 		if len(model.SupportedInputModalities) > 0 {
-			result["supportedInputModalities"] = model.SupportedInputModalities
+			result["supportedInputModalities"] = append([]string(nil), model.SupportedInputModalities...)
 		}
 		if len(model.SupportedOutputModalities) > 0 {
-			result["supportedOutputModalities"] = model.SupportedOutputModalities
+			result["supportedOutputModalities"] = append([]string(nil), model.SupportedOutputModalities...)
 		}
 		return result
 
@@ -1111,15 +1218,20 @@ func (r *ModelRegistry) CleanupExpiredQuotas() {
 
 	now := time.Now()
 	quotaExpiredDuration := 5 * time.Minute
+	invalidated := false
 
 	for modelID, registration := range r.models {
 		for clientID, quotaTime := range registration.QuotaExceededClients {
 			if quotaTime != nil && now.Sub(*quotaTime) >= quotaExpiredDuration {
 				delete(registration.QuotaExceededClients, clientID)
+				invalidated = true
 				log.Debugf("Cleaned up expired quota tracking for model %s, client %s", modelID, clientID)
 			}
 		}
 	}
+	if invalidated {
+		r.invalidateAvailableModelsCacheLocked()
+	}
 }
 
 // GetFirstAvailableModel returns the first available model for the given handler type.
@@ -1133,8 +1245,6 @@ func (r *ModelRegistry) CleanupExpiredQuotas() {
 //   - string: The model ID of the first available model, or empty string if none available
 //   - error: An error if no models are available
 func (r *ModelRegistry) GetFirstAvailableModel(handlerType string) (string, error) {
-	r.mutex.RLock()
-	defer r.mutex.RUnlock()
 
 	// Get all available models for this handler type
 	models := r.GetAvailableModels(handlerType)
@@ -1194,13 +1304,13 @@ func (r *ModelRegistry) GetModelsForClient(clientID string) []*ModelInfo {
 		// Prefer client's own model info to preserve original type/owned_by
 		if clientInfos != nil {
 			if info, ok := clientInfos[modelID]; ok && info != nil {
-				result = append(result, info)
+				result = append(result, cloneModelInfo(info))
 				continue
 			}
 		}
 		// Fallback to global registry (for backwards compatibility)
 		if reg, ok := r.models[modelID]; ok && reg.Info != nil {
-			result = append(result, reg.Info)
+			result = append(result, cloneModelInfo(reg.Info))
 		}
 	}
 	return result

internal/registry/model_registry_cache_test.go

@@ -0,0 +1,54 @@
+package registry
+
+import "testing"
+
+func TestGetAvailableModelsReturnsClonedSnapshots(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "OpenAI", []*ModelInfo{{ID: "m1", OwnedBy: "team-a", DisplayName: "Model One"}})
+
+	first := r.GetAvailableModels("openai")
+	if len(first) != 1 {
+		t.Fatalf("expected 1 model, got %d", len(first))
+	}
+	first[0]["id"] = "mutated"
+	first[0]["display_name"] = "Mutated"
+
+	second := r.GetAvailableModels("openai")
+	if got := second[0]["id"]; got != "m1" {
+		t.Fatalf("expected cached snapshot to stay isolated, got id %v", got)
+	}
+	if got := second[0]["display_name"]; got != "Model One" {
+		t.Fatalf("expected cached snapshot to stay isolated, got display_name %v", got)
+	}
+}
+
+func TestGetAvailableModelsInvalidatesCacheOnRegistryChanges(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "OpenAI", []*ModelInfo{{ID: "m1", OwnedBy: "team-a", DisplayName: "Model One"}})
+
+	models := r.GetAvailableModels("openai")
+	if len(models) != 1 {
+		t.Fatalf("expected 1 model, got %d", len(models))
+	}
+	if got := models[0]["display_name"]; got != "Model One" {
+		t.Fatalf("expected initial display_name Model One, got %v", got)
+	}
+
+	r.RegisterClient("client-1", "OpenAI", []*ModelInfo{{ID: "m1", OwnedBy: "team-a", DisplayName: "Model One Updated"}})
+	models = r.GetAvailableModels("openai")
+	if got := models[0]["display_name"]; got != "Model One Updated" {
+		t.Fatalf("expected updated display_name after cache invalidation, got %v", got)
+	}
+
+	r.SuspendClientModel("client-1", "m1", "manual")
+	models = r.GetAvailableModels("openai")
+	if len(models) != 0 {
+		t.Fatalf("expected no available models after suspension, got %d", len(models))
+	}
+
+	r.ResumeClientModel("client-1", "m1")
+	models = r.GetAvailableModels("openai")
+	if len(models) != 1 {
+		t.Fatalf("expected model to reappear after resume, got %d", len(models))
+	}
+}

internal/registry/model_registry_safety_test.go

@@ -0,0 +1,149 @@
+package registry
+
+import (
+	"testing"
+	"time"
+)
+
+func TestGetModelInfoReturnsClone(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "gemini", []*ModelInfo{{
+		ID:          "m1",
+		DisplayName: "Model One",
+		Thinking:    &ThinkingSupport{Min: 1, Max: 2, Levels: []string{"low", "high"}},
+	}})
+
+	first := r.GetModelInfo("m1", "gemini")
+	if first == nil {
+		t.Fatal("expected model info")
+	}
+	first.DisplayName = "mutated"
+	first.Thinking.Levels[0] = "mutated"
+
+	second := r.GetModelInfo("m1", "gemini")
+	if second.DisplayName != "Model One" {
+		t.Fatalf("expected cloned display name, got %q", second.DisplayName)
+	}
+	if second.Thinking == nil || len(second.Thinking.Levels) == 0 || second.Thinking.Levels[0] != "low" {
+		t.Fatalf("expected cloned thinking levels, got %+v", second.Thinking)
+	}
+}
+
+func TestGetModelsForClientReturnsClones(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "gemini", []*ModelInfo{{
+		ID:          "m1",
+		DisplayName: "Model One",
+		Thinking:    &ThinkingSupport{Levels: []string{"low", "high"}},
+	}})
+
+	first := r.GetModelsForClient("client-1")
+	if len(first) != 1 || first[0] == nil {
+		t.Fatalf("expected one model, got %+v", first)
+	}
+	first[0].DisplayName = "mutated"
+	first[0].Thinking.Levels[0] = "mutated"
+
+	second := r.GetModelsForClient("client-1")
+	if len(second) != 1 || second[0] == nil {
+		t.Fatalf("expected one model on second fetch, got %+v", second)
+	}
+	if second[0].DisplayName != "Model One" {
+		t.Fatalf("expected cloned display name, got %q", second[0].DisplayName)
+	}
+	if second[0].Thinking == nil || len(second[0].Thinking.Levels) == 0 || second[0].Thinking.Levels[0] != "low" {
+		t.Fatalf("expected cloned thinking levels, got %+v", second[0].Thinking)
+	}
+}
+
+func TestGetAvailableModelsByProviderReturnsClones(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "gemini", []*ModelInfo{{
+		ID:          "m1",
+		DisplayName: "Model One",
+		Thinking:    &ThinkingSupport{Levels: []string{"low", "high"}},
+	}})
+
+	first := r.GetAvailableModelsByProvider("gemini")
+	if len(first) != 1 || first[0] == nil {
+		t.Fatalf("expected one model, got %+v", first)
+	}
+	first[0].DisplayName = "mutated"
+	first[0].Thinking.Levels[0] = "mutated"
+
+	second := r.GetAvailableModelsByProvider("gemini")
+	if len(second) != 1 || second[0] == nil {
+		t.Fatalf("expected one model on second fetch, got %+v", second)
+	}
+	if second[0].DisplayName != "Model One" {
+		t.Fatalf("expected cloned display name, got %q", second[0].DisplayName)
+	}
+	if second[0].Thinking == nil || len(second[0].Thinking.Levels) == 0 || second[0].Thinking.Levels[0] != "low" {
+		t.Fatalf("expected cloned thinking levels, got %+v", second[0].Thinking)
+	}
+}
+
+func TestCleanupExpiredQuotasInvalidatesAvailableModelsCache(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "openai", []*ModelInfo{{ID: "m1", Created: 1}})
+	r.SetModelQuotaExceeded("client-1", "m1")
+	if models := r.GetAvailableModels("openai"); len(models) != 1 {
+		t.Fatalf("expected cooldown model to remain listed before cleanup, got %d", len(models))
+	}
+
+	r.mutex.Lock()
+	quotaTime := time.Now().Add(-6 * time.Minute)
+	r.models["m1"].QuotaExceededClients["client-1"] = &quotaTime
+	r.mutex.Unlock()
+
+	r.CleanupExpiredQuotas()
+
+	if count := r.GetModelCount("m1"); count != 1 {
+		t.Fatalf("expected model count 1 after cleanup, got %d", count)
+	}
+	models := r.GetAvailableModels("openai")
+	if len(models) != 1 {
+		t.Fatalf("expected model to stay available after cleanup, got %d", len(models))
+	}
+	if got := models[0]["id"]; got != "m1" {
+		t.Fatalf("expected model id m1, got %v", got)
+	}
+}
+
+func TestGetAvailableModelsReturnsClonedSupportedParameters(t *testing.T) {
+	r := newTestModelRegistry()
+	r.RegisterClient("client-1", "openai", []*ModelInfo{{
+		ID:                  "m1",
+		DisplayName:         "Model One",
+		SupportedParameters: []string{"temperature", "top_p"},
+	}})
+
+	first := r.GetAvailableModels("openai")
+	if len(first) != 1 {
+		t.Fatalf("expected one model, got %d", len(first))
+	}
+	params, ok := first[0]["supported_parameters"].([]string)
+	if !ok || len(params) != 2 {
+		t.Fatalf("expected supported_parameters slice, got %#v", first[0]["supported_parameters"])
+	}
+	params[0] = "mutated"
+
+	second := r.GetAvailableModels("openai")
+	params, ok = second[0]["supported_parameters"].([]string)
+	if !ok || len(params) != 2 || params[0] != "temperature" {
+		t.Fatalf("expected cloned supported_parameters, got %#v", second[0]["supported_parameters"])
+	}
+}
+
+func TestLookupModelInfoReturnsCloneForStaticDefinitions(t *testing.T) {
+	first := LookupModelInfo("glm-4.6")
+	if first == nil || first.Thinking == nil || len(first.Thinking.Levels) == 0 {
+		t.Fatalf("expected static model with thinking levels, got %+v", first)
+	}
+	first.Thinking.Levels[0] = "mutated"
+
+	second := LookupModelInfo("glm-4.6")
+	if second == nil || second.Thinking == nil || len(second.Thinking.Levels) == 0 || second.Thinking.Levels[0] == "mutated" {
+		t.Fatalf("expected static lookup clone, got %+v", second)
+	}
+}