diff --git a/cmd/root.go b/cmd/root.go
index 35adfbce..c3ac0b90 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -13,6 +13,7 @@ import (
 	"charm.land/fantasy"
 	"charm.land/lipgloss/v2"
 	"github.com/mark3labs/kit/internal/app"
+	"github.com/mark3labs/kit/internal/auth"
 	"github.com/mark3labs/kit/internal/config"
 	"github.com/mark3labs/kit/internal/extensions"
 	"github.com/mark3labs/kit/internal/models"
@@ -955,6 +956,24 @@ func runNormalMode(ctx context.Context) error {
 				kitInstance.UpdateExtensionContextModel(modelString)
 				// Fire OnModelChange event to extensions.
 				kitInstance.EmitModelChange(modelString, previousModel, "extension")
+				// Update usage tracker with new model info for correct token counting.
+				if usageTracker != nil {
+					newProvider, newModel, _ := models.ParseModelString(modelString)
+					if newProvider != "unknown" && newModel != "unknown" && newProvider != "ollama" {
+						registry := models.GetGlobalRegistry()
+						if modelInfo := registry.LookupModel(newProvider, newModel); modelInfo != nil {
+							// Check OAuth status for Anthropic models
+							isOAuth := false
+							if newProvider == "anthropic" {
+								_, source, err := auth.GetAnthropicAPIKey(viper.GetString("provider-api-key"))
+								if err == nil && strings.HasPrefix(source, "stored OAuth") {
+									isOAuth = true
+								}
+							}
+							usageTracker.UpdateModelInfo(modelInfo, newProvider, isOAuth)
+						}
+					}
+				}
 				return nil
 			},
 			GetAvailableModels: func() []extensions.ModelInfoEntry {
@@ -1152,6 +1171,24 @@ func runNormalMode(ctx context.Context) error {
 		// this callback runs synchronously inside BubbleTea's Update(), and
 		// NotifyModelChanged calls prog.Send() which deadlocks. The UI layer
 		// updates m.providerName and m.modelName directly after setModel returns.
+		// Update usage tracker with new model info for correct token counting.
+		if usageTracker != nil {
+			newProvider, newModel, _ := models.ParseModelString(modelString)
+			if newProvider != "unknown" && newModel != "unknown" && newProvider != "ollama" {
+				registry := models.GetGlobalRegistry()
+				if modelInfo := registry.LookupModel(newProvider, newModel); modelInfo != nil {
+					// Check OAuth status for Anthropic models
+					isOAuth := false
+					if newProvider == "anthropic" {
+						_, source, err := auth.GetAnthropicAPIKey(viper.GetString("provider-api-key"))
+						if err == nil && strings.HasPrefix(source, "stored OAuth") {
+							isOAuth = true
+						}
+					}
+					usageTracker.UpdateModelInfo(modelInfo, newProvider, isOAuth)
+				}
+			}
+		}
 		return nil
 	}
 	emitModelChangeForUI := func(newModel, previousModel, source string) {
diff --git a/internal/ui/usage_tracker.go b/internal/ui/usage_tracker.go
index dc42d7fc..1e6ef24f 100644
--- a/internal/ui/usage_tracker.go
+++ b/internal/ui/usage_tracker.go
@@ -266,3 +266,14 @@ func (ut *UsageTracker) SetWidth(width int) {
 	defer ut.mu.Unlock()
 	ut.width = width
 }
+
+// UpdateModelInfo updates the model information and OAuth status when the model
+// is switched mid-session. This ensures token costs and context limits are
+// calculated correctly for the new model.
+func (ut *UsageTracker) UpdateModelInfo(modelInfo *models.ModelInfo, provider string, isOAuth bool) {
+	ut.mu.Lock()
+	defer ut.mu.Unlock()
+	ut.modelInfo = modelInfo
+	ut.provider = provider
+	ut.isOAuth = isOAuth
+}