diff --git a/cmd/picoclaw/cmd_gateway.go b/cmd/picoclaw/cmd_gateway.go
index c138f837e..97fe69f4f 100644
--- a/cmd/picoclaw/cmd_gateway.go
+++ b/cmd/picoclaw/cmd_gateway.go
@@ -241,14 +241,3 @@ func setupCronTool(
 
 	return cronService
 }
-
-func getDefaultSTTBase(protocol string) string {
-	switch protocol {
-	case "openai":
-		return "https://api.openai.com/v1"
-	case "groq":
-		return "https://api.groq.com/openai/v1"
-	default:
-		return ""
-	}
-}
diff --git a/cmd/picoclaw/stt_resolution.go b/cmd/picoclaw/stt_resolution.go
index cc70d71b5..6663e7d14 100644
--- a/cmd/picoclaw/stt_resolution.go
+++ b/cmd/picoclaw/stt_resolution.go
@@ -20,7 +20,10 @@ func resolveSTTTranscriber(cfg *config.Config) voice.Transcriber {
 				protocol, modelID := providers.ExtractProtocol(mc.Model)
 				apiBase := mc.APIBase
 				if apiBase == "" {
-					apiBase = getDefaultSTTBase(protocol)
+					apiBase = providers.GetDefaultAPIBase(protocol)
+				}
+				if apiBase == "" {
+					continue // unknown protocol, skip this entry
 				}
 				return voice.NewOpenAICompatTranscriber(mc.APIKey, apiBase, modelID)
 			}
diff --git a/cmd/picoclaw/stt_resolution_test.go b/cmd/picoclaw/stt_resolution_test.go
index 3f3f16858..59a1bb32d 100644
--- a/cmd/picoclaw/stt_resolution_test.go
+++ b/cmd/picoclaw/stt_resolution_test.go
@@ -7,22 +7,28 @@ import (
 	"github.com/sipeed/picoclaw/pkg/voice"
 )
 
-func TestGetDefaultSTTBase(t *testing.T) {
-	tests := []struct {
-		protocol string
-		expected string
-	}{
-		{"openai", "https://api.openai.com/v1"},
-		{"groq", "https://api.groq.com/openai/v1"},
-		{"unknown", ""},
-		{"", ""},
+func TestResolveSTTTranscriber_UnknownProtocolSkipped(t *testing.T) {
+	// stt_model points to an entry with an unknown protocol and no api_base.
+	// The unknown protocol resolves to an empty API base, so this entry must be
+	// skipped (continue) and the function should fall through to return nil.
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				STTModel: "whisper",
+			},
+		},
+		ModelList: []config.ModelConfig{
+			{
+				ModelName: "whisper",
+				Model:     "unknownprotocol/whisper-1",
+				APIKey:    "sk-test",
+			},
+		},
 	}
-	for _, tt := range tests {
-		t.Run(tt.protocol, func(t *testing.T) {
-			if got := getDefaultSTTBase(tt.protocol); got != tt.expected {
-				t.Errorf("getDefaultSTTBase(%q) = %q, want %q", tt.protocol, got, tt.expected)
-			}
-		})
+
+	tr := resolveSTTTranscriber(cfg)
+	if tr != nil {
+		t.Error("expected nil - unknown protocol with no api_base should be skipped")
 	}
 }
 
diff --git a/pkg/providers/factory_provider.go b/pkg/providers/factory_provider.go
index 74fe8a36c..9218108a3 100644
--- a/pkg/providers/factory_provider.go
+++ b/pkg/providers/factory_provider.go
@@ -82,7 +82,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 		}
 		apiBase := cfg.APIBase
 		if apiBase == "" {
-			apiBase = getDefaultAPIBase(protocol)
+			apiBase = GetDefaultAPIBase(protocol)
 		}
 		return NewHTTPProviderWithMaxTokensField(cfg.APIKey, apiBase, cfg.Proxy, cfg.MaxTokensField), modelID, nil
 
@@ -95,7 +95,7 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 		}
 		apiBase := cfg.APIBase
 		if apiBase == "" {
-			apiBase = getDefaultAPIBase(protocol)
+			apiBase = GetDefaultAPIBase(protocol)
 		}
 		return NewHTTPProviderWithMaxTokensField(cfg.APIKey, apiBase, cfg.Proxy, cfg.MaxTokensField), modelID, nil
 
@@ -155,8 +155,9 @@ func CreateProviderFromConfig(cfg *config.ModelConfig) (LLMProvider, string, err
 	}
 }
 
-// getDefaultAPIBase returns the default API base URL for a given protocol.
-func getDefaultAPIBase(protocol string) string {
+// GetDefaultAPIBase returns the default API base URL for a given protocol.
+// Returns an empty string if the protocol is unknown.
+func GetDefaultAPIBase(protocol string) string {
 	switch protocol {
 	case "openai":
 		return "https://api.openai.com/v1"