diff --git a/internal/registry/model_registry.go b/internal/registry/model_registry.go
index 8f56c43d..74ad6acf 100644
--- a/internal/registry/model_registry.go
+++ b/internal/registry/model_registry.go
@@ -187,6 +187,7 @@ func (r *ModelRegistry) SetHook(hook ModelRegistryHook) {
 }
 
 const defaultModelRegistryHookTimeout = 5 * time.Second
+const modelQuotaExceededWindow = 5 * time.Minute
 
 func (r *ModelRegistry) triggerModelsRegistered(provider, clientID string, models []*ModelInfo) {
 	hook := r.hook
@@ -388,6 +389,9 @@ func (r *ModelRegistry) RegisterClient(clientID, clientProvider string, models [
 				reg.InfoByProvider[provider] = cloneModelInfo(model)
 			}
 			reg.LastUpdated = now
+			// Re-registering an existing client/model binding starts a fresh registry
+			// snapshot for that binding. Cooldown and suspension are transient
+			// scheduling state and must not survive this reconciliation step.
 			if reg.QuotaExceededClients != nil {
 				delete(reg.QuotaExceededClients, clientID)
 			}
@@ -781,7 +785,6 @@ func (r *ModelRegistry) GetAvailableModels(handlerType string) []map[string]any
 
 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 {
@@ -792,7 +795,7 @@ func (r *ModelRegistry) buildAvailableModelsLocked(handlerType string, now time.
 			if quotaTime == nil {
 				continue
 			}
-			recoveryAt := quotaTime.Add(quotaExpiredDuration)
+			recoveryAt := quotaTime.Add(modelQuotaExceededWindow)
 			if now.Before(recoveryAt) {
 				expiredClients++
 				if expiresAt.IsZero() || recoveryAt.Before(expiresAt) {
@@ -927,7 +930,6 @@ func (r *ModelRegistry) GetAvailableModelsByProvider(provider string) []*ModelIn
 		return nil
 	}
 
-	quotaExpiredDuration := 5 * time.Minute
 	now := time.Now()
 	result := make([]*ModelInfo, 0, len(providerModels))
 
@@ -949,7 +951,7 @@ func (r *ModelRegistry) GetAvailableModelsByProvider(provider string) []*ModelIn
 					if p, okProvider := r.clientProviders[clientID]; !okProvider || p != provider {
 						continue
 					}
-					if quotaTime != nil && now.Sub(*quotaTime) < quotaExpiredDuration {
+					if quotaTime != nil && now.Sub(*quotaTime) < modelQuotaExceededWindow {
 						expiredClients++
 					}
 				}
@@ -1003,12 +1005,11 @@ func (r *ModelRegistry) GetModelCount(modelID string) int {
 
 	if registration, exists := r.models[modelID]; exists {
 		now := time.Now()
-		quotaExpiredDuration := 5 * time.Minute
 
 		// Count clients that have exceeded quota but haven't recovered yet
 		expiredClients := 0
 		for _, quotaTime := range registration.QuotaExceededClients {
-			if quotaTime != nil && now.Sub(*quotaTime) < quotaExpiredDuration {
+			if quotaTime != nil && now.Sub(*quotaTime) < modelQuotaExceededWindow {
 				expiredClients++
 			}
 		}
@@ -1217,12 +1218,11 @@ func (r *ModelRegistry) CleanupExpiredQuotas() {
 	defer r.mutex.Unlock()
 
 	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 {
+			if quotaTime != nil && now.Sub(*quotaTime) >= modelQuotaExceededWindow {
 				delete(registration.QuotaExceededClients, clientID)
 				invalidated = true
 				log.Debugf("Cleaned up expired quota tracking for model %s, client %s", modelID, clientID)
diff --git a/internal/registry/model_updater.go b/internal/registry/model_updater.go
index 36d2dd32..197f6044 100644
--- a/internal/registry/model_updater.go
+++ b/internal/registry/model_updater.go
@@ -15,7 +15,8 @@ import (
 )
 
 const (
-	modelsFetchTimeout = 30 * time.Second
+	modelsFetchTimeout    = 30 * time.Second
+	modelsRefreshInterval = 3 * time.Hour
 )
 
 var modelsURLs = []string{
@@ -35,6 +36,34 @@ var modelsCatalogStore = &modelStore{}
 
 var updaterOnce sync.Once
 
+// ModelRefreshCallback is invoked when startup or periodic model refresh detects changes.
+// changedProviders contains the provider names whose model definitions changed.
+type ModelRefreshCallback func(changedProviders []string)
+
+var (
+	refreshCallbackMu     sync.Mutex
+	refreshCallback       ModelRefreshCallback
+	pendingRefreshChanges []string
+)
+
+// SetModelRefreshCallback registers a callback that is invoked when startup or
+// periodic model refresh detects changes. Only one callback is supported;
+// subsequent calls replace the previous callback.
+func SetModelRefreshCallback(cb ModelRefreshCallback) {
+	refreshCallbackMu.Lock()
+	refreshCallback = cb
+	var pending []string
+	if cb != nil && len(pendingRefreshChanges) > 0 {
+		pending = append([]string(nil), pendingRefreshChanges...)
+		pendingRefreshChanges = nil
+	}
+	refreshCallbackMu.Unlock()
+
+	if cb != nil && len(pending) > 0 {
+		cb(pending)
+	}
+}
+
 func init() {
 	// Load embedded data as fallback on startup.
 	if err := loadModelsFromBytes(embeddedModelsJSON, "embed"); err != nil {
@@ -42,23 +71,76 @@ func init() {
 	}
 }
 
-// StartModelsUpdater runs a one-time models refresh on startup.
-// It blocks until the startup fetch attempt finishes so service initialization
-// can wait for the refreshed catalog before registering auth-backed models.
-// Safe to call multiple times; only one refresh will run.
+// StartModelsUpdater starts a background updater that fetches models
+// immediately on startup and then refreshes the model catalog every 3 hours.
+// Safe to call multiple times; only one updater will run.
 func StartModelsUpdater(ctx context.Context) {
 	updaterOnce.Do(func() {
-		runModelsUpdater(ctx)
+		go runModelsUpdater(ctx)
 	})
 }
 
 func runModelsUpdater(ctx context.Context) {
-	// Try network fetch once on startup, then stop.
-	// Periodic refresh is disabled - models are only refreshed at startup.
-	tryRefreshModels(ctx)
+	tryStartupRefresh(ctx)
+	periodicRefresh(ctx)
 }
 
-func tryRefreshModels(ctx context.Context) {
+func periodicRefresh(ctx context.Context) {
+	ticker := time.NewTicker(modelsRefreshInterval)
+	defer ticker.Stop()
+	log.Infof("periodic model refresh started (interval=%s)", modelsRefreshInterval)
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			tryPeriodicRefresh(ctx)
+		}
+	}
+}
+
+// tryPeriodicRefresh fetches models from remote, compares with the current
+// catalog, and notifies the registered callback if any provider changed.
+func tryPeriodicRefresh(ctx context.Context) {
+	tryRefreshModels(ctx, "periodic model refresh")
+}
+
+// tryStartupRefresh fetches models from remote in the background during
+// process startup. It uses the same change detection as periodic refresh so
+// existing auth registrations can be updated after the callback is registered.
+func tryStartupRefresh(ctx context.Context) {
+	tryRefreshModels(ctx, "startup model refresh")
+}
+
+func tryRefreshModels(ctx context.Context, label string) {
+	oldData := getModels()
+
+	parsed, url := fetchModelsFromRemote(ctx)
+	if parsed == nil {
+		log.Warnf("%s: fetch failed from all URLs, keeping current data", label)
+		return
+	}
+
+	// Detect changes before updating store.
+	changed := detectChangedProviders(oldData, parsed)
+
+	// Update store with new data regardless.
+	modelsCatalogStore.mu.Lock()
+	modelsCatalogStore.data = parsed
+	modelsCatalogStore.mu.Unlock()
+
+	if len(changed) == 0 {
+		log.Infof("%s completed from %s, no changes detected", label, url)
+		return
+	}
+
+	log.Infof("%s completed from %s, changes detected for providers: %v", label, url, changed)
+	notifyModelRefresh(changed)
+}
+
+// fetchModelsFromRemote tries all remote URLs and returns the parsed model catalog
+// along with the URL it was fetched from. Returns (nil, "") if all fetches fail.
+func fetchModelsFromRemote(ctx context.Context) (*staticModelsJSON, string) {
 	client := &http.Client{Timeout: modelsFetchTimeout}
 	for _, url := range modelsURLs {
 		reqCtx, cancel := context.WithTimeout(ctx, modelsFetchTimeout)
@@ -92,15 +174,126 @@ func tryRefreshModels(ctx context.Context) {
 			continue
 		}
 
-		if err := loadModelsFromBytes(data, url); err != nil {
+		var parsed staticModelsJSON
+		if err := json.Unmarshal(data, &parsed); err != nil {
 			log.Warnf("models parse failed from %s: %v", url, err)
 			continue
 		}
+		if err := validateModelsCatalog(&parsed); err != nil {
+			log.Warnf("models validate failed from %s: %v", url, err)
+			continue
+		}
 
-		log.Infof("models updated from %s", url)
+		return &parsed, url
+	}
+	return nil, ""
+}
+
+// detectChangedProviders compares two model catalogs and returns provider names
+// whose model definitions differ. Codex tiers (free/team/plus/pro) are grouped
+// under a single "codex" provider.
+func detectChangedProviders(oldData, newData *staticModelsJSON) []string {
+	if oldData == nil || newData == nil {
+		return nil
+	}
+
+	type section struct {
+		provider string
+		oldList  []*ModelInfo
+		newList  []*ModelInfo
+	}
+
+	sections := []section{
+		{"claude", oldData.Claude, newData.Claude},
+		{"gemini", oldData.Gemini, newData.Gemini},
+		{"vertex", oldData.Vertex, newData.Vertex},
+		{"gemini-cli", oldData.GeminiCLI, newData.GeminiCLI},
+		{"aistudio", oldData.AIStudio, newData.AIStudio},
+		{"codex", oldData.CodexFree, newData.CodexFree},
+		{"codex", oldData.CodexTeam, newData.CodexTeam},
+		{"codex", oldData.CodexPlus, newData.CodexPlus},
+		{"codex", oldData.CodexPro, newData.CodexPro},
+		{"qwen", oldData.Qwen, newData.Qwen},
+		{"iflow", oldData.IFlow, newData.IFlow},
+		{"kimi", oldData.Kimi, newData.Kimi},
+		{"antigravity", oldData.Antigravity, newData.Antigravity},
+	}
+
+	seen := make(map[string]bool, len(sections))
+	var changed []string
+	for _, s := range sections {
+		if seen[s.provider] {
+			continue
+		}
+		if modelSectionChanged(s.oldList, s.newList) {
+			changed = append(changed, s.provider)
+			seen[s.provider] = true
+		}
+	}
+	return changed
+}
+
+// modelSectionChanged reports whether two model slices differ.
+func modelSectionChanged(a, b []*ModelInfo) bool {
+	if len(a) != len(b) {
+		return true
+	}
+	if len(a) == 0 {
+		return false
+	}
+	aj, err1 := json.Marshal(a)
+	bj, err2 := json.Marshal(b)
+	if err1 != nil || err2 != nil {
+		return true
+	}
+	return string(aj) != string(bj)
+}
+
+func notifyModelRefresh(changedProviders []string) {
+	if len(changedProviders) == 0 {
 		return
 	}
-	log.Warn("models refresh failed from all URLs, using local data")
+
+	refreshCallbackMu.Lock()
+	cb := refreshCallback
+	if cb == nil {
+		pendingRefreshChanges = mergeProviderNames(pendingRefreshChanges, changedProviders)
+		refreshCallbackMu.Unlock()
+		return
+	}
+	refreshCallbackMu.Unlock()
+	cb(changedProviders)
+}
+
+func mergeProviderNames(existing, incoming []string) []string {
+	if len(incoming) == 0 {
+		return existing
+	}
+	seen := make(map[string]struct{}, len(existing)+len(incoming))
+	merged := make([]string, 0, len(existing)+len(incoming))
+	for _, provider := range existing {
+		name := strings.ToLower(strings.TrimSpace(provider))
+		if name == "" {
+			continue
+		}
+		if _, ok := seen[name]; ok {
+			continue
+		}
+		seen[name] = struct{}{}
+		merged = append(merged, name)
+	}
+	for _, provider := range incoming {
+		name := strings.ToLower(strings.TrimSpace(provider))
+		if name == "" {
+			continue
+		}
+		if _, ok := seen[name]; ok {
+			continue
+		}
+		seen[name] = struct{}{}
+		merged = append(merged, name)
+	}
+	return merged
 }
 
 func loadModelsFromBytes(data []byte, source string) error {
diff --git a/sdk/cliproxy/service.go b/sdk/cliproxy/service.go
index af31f86a..abe1deed 100644
--- a/sdk/cliproxy/service.go
+++ b/sdk/cliproxy/service.go
@@ -434,6 +434,17 @@ func (s *Service) ensureExecutorsForAuthWithMode(a *coreauth.Auth, forceReplace
 	}
 }
 
+func (s *Service) registerResolvedModelsForAuth(a *coreauth.Auth, providerKey string, models []*ModelInfo) {
+	if a == nil || a.ID == "" {
+		return
+	}
+	if len(models) == 0 {
+		GlobalModelRegistry().UnregisterClient(a.ID)
+		return
+	}
+	GlobalModelRegistry().RegisterClient(a.ID, providerKey, models)
+}
+
 // rebindExecutors refreshes provider executors so they observe the latest configuration.
 func (s *Service) rebindExecutors() {
 	if s == nil || s.coreManager == nil {
@@ -541,6 +552,44 @@ func (s *Service) Run(ctx context.Context) error {
 		s.hooks.OnBeforeStart(s.cfg)
 	}
 
+	// Register callback for startup and periodic model catalog refresh.
+	// When remote model definitions change, re-register models for affected providers.
+	// This intentionally rebuilds per-auth model availability from the latest catalog
+	// snapshot instead of preserving prior registry suppression state.
+	registry.SetModelRefreshCallback(func(changedProviders []string) {
+		if s == nil || s.coreManager == nil || len(changedProviders) == 0 {
+			return
+		}
+
+		providerSet := make(map[string]bool, len(changedProviders))
+		for _, p := range changedProviders {
+			providerSet[strings.ToLower(strings.TrimSpace(p))] = true
+		}
+
+		auths := s.coreManager.List()
+		refreshed := 0
+		for _, item := range auths {
+			if item == nil || item.ID == "" {
+				continue
+			}
+			auth, ok := s.coreManager.GetByID(item.ID)
+			if !ok || auth == nil || auth.Disabled {
+				continue
+			}
+			provider := strings.ToLower(strings.TrimSpace(auth.Provider))
+			if !providerSet[provider] {
+				continue
+			}
+			if s.refreshModelRegistrationForAuth(auth) {
+				refreshed++
+			}
+		}
+
+		if refreshed > 0 {
+			log.Infof("re-registered models for %d auth(s) due to model catalog changes: %v", refreshed, changedProviders)
+		}
+	})
+
 	s.serverErr = make(chan error, 1)
 	go func() {
 		if errStart := s.server.Start(); errStart != nil {
@@ -926,7 +975,7 @@ func (s *Service) registerModelsForAuth(a *coreauth.Auth) {
 						if providerKey == "" {
 							providerKey = "openai-compatibility"
 						}
-						GlobalModelRegistry().RegisterClient(a.ID, providerKey, applyModelPrefixes(ms, a.Prefix, s.cfg.ForceModelPrefix))
+						s.registerResolvedModelsForAuth(a, providerKey, applyModelPrefixes(ms, a.Prefix, s.cfg.ForceModelPrefix))
 					} else {
 						// Ensure stale registrations are cleared when model list becomes empty.
 						GlobalModelRegistry().UnregisterClient(a.ID)
@@ -947,13 +996,60 @@ func (s *Service) registerModelsForAuth(a *coreauth.Auth) {
 		if key == "" {
 			key = strings.ToLower(strings.TrimSpace(a.Provider))
 		}
-		GlobalModelRegistry().RegisterClient(a.ID, key, applyModelPrefixes(models, a.Prefix, s.cfg != nil && s.cfg.ForceModelPrefix))
+		s.registerResolvedModelsForAuth(a, key, applyModelPrefixes(models, a.Prefix, s.cfg != nil && s.cfg.ForceModelPrefix))
 		return
 	}
 
 	GlobalModelRegistry().UnregisterClient(a.ID)
 }
 
+// refreshModelRegistrationForAuth re-applies the latest model registration for
+// one auth and reconciles any concurrent auth changes that race with the
+// refresh. Callers are expected to pre-filter provider membership.
+//
+// Re-registration is deliberate: registry cooldown/suspension state is treated
+// as part of the previous registration snapshot and is cleared when the auth is
+// rebound to the refreshed model catalog.
+func (s *Service) refreshModelRegistrationForAuth(current *coreauth.Auth) bool {
+	if s == nil || s.coreManager == nil || current == nil || current.ID == "" {
+		return false
+	}
+
+	if !current.Disabled {
+		s.ensureExecutorsForAuth(current)
+	}
+	s.registerModelsForAuth(current)
+
+	latest, ok := s.latestAuthForModelRegistration(current.ID)
+	if !ok || latest.Disabled {
+		GlobalModelRegistry().UnregisterClient(current.ID)
+		s.coreManager.RefreshSchedulerEntry(current.ID)
+		return false
+	}
+
+	// Re-apply the latest auth snapshot so concurrent auth updates cannot leave
+	// stale model registrations behind. This may duplicate registration work when
+	// no auth fields changed, but keeps the refresh path simple and correct.
+	s.ensureExecutorsForAuth(latest)
+	s.registerModelsForAuth(latest)
+	s.coreManager.RefreshSchedulerEntry(current.ID)
+	return true
+}
+
+// latestAuthForModelRegistration returns the latest auth snapshot regardless of
+// provider membership. Callers use this after a registration attempt to restore
+// whichever state currently owns the client ID in the global registry.
+func (s *Service) latestAuthForModelRegistration(authID string) (*coreauth.Auth, bool) {
+	if s == nil || s.coreManager == nil || authID == "" {
+		return nil, false
+	}
+	auth, ok := s.coreManager.GetByID(authID)
+	if !ok || auth == nil || auth.ID == "" {
+		return nil, false
+	}
+	return auth, true
+}
+
 func (s *Service) resolveConfigClaudeKey(auth *coreauth.Auth) *config.ClaudeKey {
 	if auth == nil || s.cfg == nil {
 		return nil