diff --git a/README.zh.md b/README.zh.md
index 5d3af50ca..5e90f2b3a 100644
--- a/README.zh.md
+++ b/README.zh.md
@@ -748,3 +748,4 @@ Discord:  [https://discord.gg/V4sAZ9XWpN](https://discord.gg/V4sAZ9XWpN)
 | **智谱 (Zhipu)** | 200K tokens/月 | 最适合中国用户 |
 | **Brave Search** | 2000 次查询/月 | 网络搜索功能 |
 | **Groq** | 提供免费层级 | 极速推理 (Llama, Mixtral) |
+| **Cerebras** | 提供免费层级 | 极速推理 (Llama, Qwen 等) |
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 808991d5c..917a4887c 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -6,7 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"sync"
+	"sync/atomic"
 
 	"github.com/caarlos0/env/v11"
 	"github.com/go-viper/mapstructure/v2"
@@ -56,9 +56,11 @@ type Config struct {
 	Tools     ToolsConfig     `json:"tools"`
 	Heartbeat HeartbeatConfig `json:"heartbeat"`
 	Devices   DevicesConfig   `json:"devices"`
-	mu        sync.RWMutex
 }
 
+// rrCounter is reserved for round-robin model selection compatibility.
+var rrCounter atomic.Uint64
+
 var configFileNames = []string{
 	"config.json",
 	"config.yaml",
@@ -523,9 +525,6 @@ func LoadConfig(path string) (*Config, error) {
 }
 
 func SaveConfig(path string, cfg *Config) error {
-	cfg.mu.RLock()
-	defer cfg.mu.RUnlock()
-
 	ext := filepath.Ext(path)
 	var configType string
 	switch ext {
@@ -587,14 +586,10 @@ func ResolveConfigPath(home string) string {
 }
 
 func (c *Config) WorkspacePath() string {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
 	return expandHome(c.Agents.Defaults.Workspace)
 }
 
 func (c *Config) GetAPIKey() string {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
 	if c.Providers.OpenRouter.APIKey != "" {
 		return c.Providers.OpenRouter.APIKey
 	}
@@ -623,8 +618,6 @@ func (c *Config) GetAPIKey() string {
 }
 
 func (c *Config) GetAPIBase() string {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
 	if c.Providers.OpenRouter.APIKey != "" {
 		if c.Providers.OpenRouter.APIBase != "" {
 			return c.Providers.OpenRouter.APIBase
@@ -648,8 +641,6 @@ type ModelConfig struct {
 
 // GetModelConfig returns the text model configuration with fallbacks.
 func (c *Config) GetModelConfig() ModelConfig {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
 	return ModelConfig{
 		Primary:   c.Agents.Defaults.Model,
 		Fallbacks: c.Agents.Defaults.ModelFallbacks,
@@ -658,8 +649,6 @@ func (c *Config) GetModelConfig() ModelConfig {
 
 // GetImageModelConfig returns the image model configuration with fallbacks.
 func (c *Config) GetImageModelConfig() ModelConfig {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
 	return ModelConfig{
 		Primary:   c.Agents.Defaults.ImageModel,
 		Fallbacks: c.Agents.Defaults.ImageModelFallbacks,