fix: add root Codex models alias

backend/internal/server/routes/gateway.go

@@ -42,6 +42,13 @@ func RegisterGatewayRoutes(
 	isOpenAIGatewayPlatform := func(c *gin.Context) bool {
 		return getGroupPlatform(c) == service.PlatformOpenAI
 	}
+	modelsHandler := func(c *gin.Context) {
+		if isOpenAIGatewayPlatform(c) && c.Query("client_version") != "" {
+			h.OpenAIGateway.CodexModels(c)
+			return
+		}
+		h.Gateway.Models(c)
+	}
 	imagesHandler := func(c *gin.Context) {
 		switch getGroupPlatform(c) {
 		case service.PlatformOpenAI:
@@ -140,13 +147,7 @@ func RegisterGatewayRoutes(
 		// Codex CLI / Codex app refresh their model picker from the provider's
 		// /models endpoint with a client_version query and expect the ChatGPT
 		// Codex manifest format; other clients keep the OpenAI-style list.
-		gateway.GET("/models", func(c *gin.Context) {
-			if isOpenAIGatewayPlatform(c) && c.Query("client_version") != "" {
-				h.OpenAIGateway.CodexModels(c)
-				return
-			}
-			h.Gateway.Models(c)
-		})
+		gateway.GET("/models", modelsHandler)
 		gateway.GET("/usage", h.Gateway.Usage)
 		// OpenAI Responses API: auto-route based on group platform
 		gateway.POST("/responses", func(c *gin.Context) {
@@ -235,6 +236,7 @@ func RegisterGatewayRoutes(
 	r.GET("/responses", bodyLimit, clientRequestID, opsErrorLogger, endpointNorm, gin.HandlerFunc(apiKeyAuth), requireGroupAnthropic, func(c *gin.Context) {
 		h.OpenAIGateway.ResponsesWebSocket(c)
 	})
+	r.GET("/models", bodyLimit, clientRequestID, opsErrorLogger, endpointNorm, gin.HandlerFunc(apiKeyAuth), requireGroupAnthropic, modelsHandler)
 	codexDirect := r.Group("/backend-api/codex")
 	codexDirect.Use(bodyLimit, clientRequestID, opsErrorLogger, endpointNorm, gin.HandlerFunc(apiKeyAuth), requireGroupAnthropic)
 	{

backend/internal/server/routes/gateway_codex_models_test.go

@@ -10,13 +10,15 @@ import (
 func TestGatewayRoutesCodexModelsManifestPathIsRegistered(t *testing.T) {
 	router := newGatewayRoutesTestRouter()
 
-	registered := make(map[string]bool)
+	registered := make(map[string]string)
 	for _, route := range router.Routes() {
 		if route.Method == http.MethodGet {
-			registered[route.Path] = true
+			registered[route.Path] = route.Handler
 		}
 	}
 
-	require.True(t, registered["/backend-api/codex/models"], "GET /backend-api/codex/models should be registered")
-	require.True(t, registered["/v1/models"], "GET /v1/models should be registered")
+	require.NotEmpty(t, registered["/backend-api/codex/models"], "GET /backend-api/codex/models should be registered")
+	require.NotEmpty(t, registered["/v1/models"], "GET /v1/models should be registered")
+	require.NotEmpty(t, registered["/models"], "GET /models should be registered")
+	require.Equal(t, registered["/v1/models"], registered["/models"], "root alias should use the same platform-aware handler")
 }

backend/internal/web/embed_on.go

@@ -310,6 +310,7 @@ func shouldBypassEmbeddedFrontend(path string) bool {
 		strings.HasPrefix(trimmed, "/antigravity/") ||
 		strings.HasPrefix(trimmed, "/setup/") ||
 		trimmed == "/health" ||
+		trimmed == "/models" ||
 		trimmed == "/responses" ||
 		strings.HasPrefix(trimmed, "/responses/") ||
 		trimmed == "/alpha/search" ||

backend/internal/web/embed_test.go

@@ -451,6 +451,7 @@ func TestFrontendServer_Middleware(t *testing.T) {
 
 		apiPaths := []string{
 			"/api/v1/users",
+			"/models",
 			"/v1/models",
 			"/v1beta/chat",
 			"/backend-api/codex/responses",
@@ -692,6 +693,7 @@ func TestServeEmbeddedFrontend(t *testing.T) {
 
 		apiPaths := []string{
 			"/api/users",
+			"/models",
 			"/v1/models",
 			"/v1beta/chat",
 			"/backend-api/codex/responses",