diff --git a/agent/llm/providers/openai/openai.go b/agent/llm/providers/openai/openai.go
index 52d0afa4..264b5a80 100644
--- a/agent/llm/providers/openai/openai.go
+++ b/agent/llm/providers/openai/openai.go
@@ -129,17 +129,11 @@ type Provider struct {
 	adapters []adapters.CapabilityAdapter
 }
 
-// buildAPIURL builds the complete API URL from host and endpoint
-// If host ends with /, it's used as-is (user has specified full path)
-// Otherwise, /v1 prefix is added automatically (standard for OpenAI-compatible APIs)
+// buildAPIURL builds the complete API URL from host and endpoint.
+// Delegates to the shared connector.BuildAPIURL for consistent URL building
+// across the agent LLM path and the sandbox proxy path.
 func buildAPIURL(host, endpoint string) string {
-	// If host ends with /, use it as-is (user has specified full path like /v1/ or /api/)
-	// Otherwise, add /v1 prefix (standard for OpenAI-compatible APIs)
-	if !strings.HasSuffix(host, "/") {
-		endpoint = "/v1" + endpoint
-	}
-	host = strings.TrimSuffix(host, "/")
-	return host + endpoint
+	return connector.BuildAPIURL(host, endpoint)
 }
 
 // New create a new OpenAI provider with capability adapters
diff --git a/agent/sandbox/claude/command.go b/agent/sandbox/claude/command.go
index 7736206f..e2e4648d 100644
--- a/agent/sandbox/claude/command.go
+++ b/agent/sandbox/claude/command.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"strings"
 
+	"github.com/yaoapp/gou/connector"
 	agentContext "github.com/yaoapp/yao/agent/context"
 )
 
@@ -355,11 +356,9 @@ func BuildProxyConfig(opts *Options) ([]byte, error) {
 		return nil, fmt.Errorf("options is required")
 	}
 
-	// Build backend URL - ensure it ends with /chat/completions
-	backendURL := opts.ConnectorHost
-	if !strings.HasSuffix(backendURL, "/chat/completions") {
-		backendURL = strings.TrimSuffix(backendURL, "/") + "/chat/completions"
-	}
+	// Build backend URL using the shared connector.BuildAPIURL helper
+	// so that the /v1 prefix is applied consistently with the agent LLM path.
+	backendURL := connector.BuildAPIURL(opts.ConnectorHost, "/chat/completions")
 
 	config := map[string]interface{}{
 		"backend": backendURL,