diff --git a/cmd/picoclaw-launcher-tui/config/config.go b/cmd/picoclaw-launcher-tui/config/config.go
index 28bee27cd..64d479285 100644
--- a/cmd/picoclaw-launcher-tui/config/config.go
+++ b/cmd/picoclaw-launcher-tui/config/config.go
@@ -8,6 +8,7 @@ package config
 
 import (
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -149,6 +150,78 @@ func (p *Provider) UsersForScheme(schemeName string) []User {
 	return out
 }
 
+// SyncSelectedModelToMainConfig syncs the currently selected model to ~/.picoclaw/config.json
+// Adds/replaces a "tui-prefer" model entry and sets it as the default model.
+// Preserves all other existing fields in the config file unchanged.
+func SyncSelectedModelToMainConfig(scheme Scheme, user User, modelID string) error {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		home = "."
+	}
+	mainConfigPath := filepath.Join(home, ".picoclaw", "config.json")
+
+	var cfg map[string]interface{}
+	if data, err := os.ReadFile(mainConfigPath); err == nil {
+		if err := json.Unmarshal(data, &cfg); err != nil {
+			cfg = make(map[string]interface{})
+		}
+	} else {
+		cfg = make(map[string]interface{})
+	}
+
+	if _, ok := cfg["agents"]; !ok {
+		cfg["agents"] = make(map[string]interface{})
+	}
+	agents, ok := cfg["agents"].(map[string]interface{})
+	if ok {
+		if _, ok := agents["defaults"]; !ok {
+			agents["defaults"] = make(map[string]interface{})
+		}
+		defaults, ok := agents["defaults"].(map[string]interface{})
+		if ok {
+			defaults["model"] = "tui-prefer"
+		}
+	}
+
+	tuiModel := map[string]interface{}{
+		"model_name": "tui-prefer",
+		"model":      modelID,
+		"api_key":    user.Key,
+		"api_base":   scheme.BaseURL,
+	}
+
+	modelList := []interface{}{}
+	if ml, ok := cfg["model_list"].([]interface{}); ok {
+		modelList = ml
+	}
+
+	found := false
+	for i, m := range modelList {
+		if entry, ok := m.(map[string]interface{}); ok {
+			if name, ok := entry["model_name"].(string); ok && name == "tui-prefer" {
+				modelList[i] = tuiModel
+				found = true
+				break
+			}
+		}
+	}
+	if !found {
+		modelList = append(modelList, tuiModel)
+	}
+	cfg["model_list"] = modelList
+
+	data, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return err
+	}
+
+	if err := os.MkdirAll(filepath.Dir(mainConfigPath), 0o700); err != nil {
+		return err
+	}
+
+	return os.WriteFile(mainConfigPath, data, 0o600)
+}
+
 func (cfg *TUIConfig) CurrentModelLabel() string {
 	cur := cfg.Provider.Current
 	if cur.Model == "" {
diff --git a/cmd/picoclaw-launcher-tui/main.go b/cmd/picoclaw-launcher-tui/main.go
index 3d7e62b08..057206ab1 100644
--- a/cmd/picoclaw-launcher-tui/main.go
+++ b/cmd/picoclaw-launcher-tui/main.go
@@ -26,6 +26,10 @@ func main() {
 	}
 
 	app := ui.New(cfg, configPath)
+	// Bind model selection hook to sync to main config
+	app.OnModelSelected = func(scheme tuicfg.Scheme, user tuicfg.User, modelID string) {
+		_ = tuicfg.SyncSelectedModelToMainConfig(scheme, user, modelID)
+	}
 	if err := app.Run(); err != nil {
 		fmt.Fprintf(os.Stderr, "picoclaw-launcher-tui: %v\n", err)
 		os.Exit(1)
diff --git a/cmd/picoclaw-launcher-tui/ui/app.go b/cmd/picoclaw-launcher-tui/ui/app.go
index 53d1cf8cd..4978935d9 100644
--- a/cmd/picoclaw-launcher-tui/ui/app.go
+++ b/cmd/picoclaw-launcher-tui/ui/app.go
@@ -25,6 +25,10 @@ type App struct {
 	headerModelTV  *tview.TextView
 	modalOpen      map[string]bool
 
+	// OnModelSelected is called when a model is selected in the UI.
+	// Can be nil to disable.
+	OnModelSelected func(scheme tuicfg.Scheme, user tuicfg.User, modelID string)
+
 	modelCache   map[string][]modelEntry
 	modelCacheMu sync.RWMutex
 	refreshMu    sync.Mutex
diff --git a/cmd/picoclaw-launcher-tui/ui/models.go b/cmd/picoclaw-launcher-tui/ui/models.go
index 46daaeb3e..1f9484b26 100644
--- a/cmd/picoclaw-launcher-tui/ui/models.go
+++ b/cmd/picoclaw-launcher-tui/ui/models.go
@@ -116,6 +116,24 @@ func (a *App) newModelsPage(schemeName, userName, baseURL string) tview.Primitiv
 			Model:  modelIDs[row],
 		}
 		a.save()
+
+		// Trigger model selected callback if set
+		if a.OnModelSelected != nil && a.cfg.Model.Type == "provider" {
+			scheme := a.cfg.Provider.SchemeByName(schemeName)
+			if scheme == nil {
+				a.goBack()
+				return
+			}
+			var user tuicfg.User
+			for _, u := range a.cfg.Provider.Users {
+				if u.Scheme == schemeName && u.Name == userName {
+					user = u
+					break
+				}
+			}
+			a.OnModelSelected(*scheme, user, modelIDs[row])
+		}
+
 		a.goBack()
 	})