diff --git a/internal/api/server.go b/internal/api/server.go
index 7c571e23c..32ae3164f 100644
--- a/internal/api/server.go
+++ b/internal/api/server.go
@@ -353,6 +353,15 @@ func (s *Server) setupRoutes() {
 		v1.POST("/responses/compact", openaiResponsesHandlers.Compact)
 	}
 
+	// Codex CLI direct route aliases (chatgpt_base_url compatible)
+	codexDirect := s.engine.Group("/backend-api/codex")
+	codexDirect.Use(AuthMiddleware(s.accessManager))
+	{
+		codexDirect.GET("/responses", openaiResponsesHandlers.ResponsesWebsocket)
+		codexDirect.POST("/responses", openaiResponsesHandlers.Responses)
+		codexDirect.POST("/responses/compact", openaiResponsesHandlers.Compact)
+	}
+
 	// Gemini compatible API routes
 	v1beta := s.engine.Group("/v1beta")
 	v1beta.Use(AuthMiddleware(s.accessManager))
diff --git a/internal/runtime/executor/codex_executor.go b/internal/runtime/executor/codex_executor.go
index 7d4d3edf8..543e2c277 100644
--- a/internal/runtime/executor/codex_executor.go
+++ b/internal/runtime/executor/codex_executor.go
@@ -180,6 +180,7 @@ func (e *CodexExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, re
 	body, _ = sjson.DeleteBytes(body, "safety_identifier")
 	body, _ = sjson.DeleteBytes(body, "stream_options")
 	body = normalizeCodexInstructions(body)
+	body = ensureImageGenerationTool(body)
 
 	url := strings.TrimSuffix(baseURL, "/") + "/responses"
 	httpReq, err := e.cacheHelper(ctx, from, url, req, body)
@@ -326,6 +327,7 @@ func (e *CodexExecutor) executeCompact(ctx context.Context, auth *cliproxyauth.A
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 	body, _ = sjson.DeleteBytes(body, "stream")
 	body = normalizeCodexInstructions(body)
+	body = ensureImageGenerationTool(body)
 
 	url := strings.TrimSuffix(baseURL, "/") + "/responses/compact"
 	httpReq, err := e.cacheHelper(ctx, from, url, req, body)
@@ -420,6 +422,7 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 	body, _ = sjson.DeleteBytes(body, "stream_options")
 	body, _ = sjson.SetBytes(body, "model", baseModel)
 	body = normalizeCodexInstructions(body)
+	body = ensureImageGenerationTool(body)
 
 	url := strings.TrimSuffix(baseURL, "/") + "/responses"
 	httpReq, err := e.cacheHelper(ctx, from, url, req, body)
@@ -821,6 +824,24 @@ func normalizeCodexInstructions(body []byte) []byte {
 	return body
 }
 
+var imageGenToolJSON = []byte(`{"type":"image_generation","output_format":"png"}`)
+var imageGenToolArrayJSON = []byte(`[{"type":"image_generation","output_format":"png"}]`)
+
+func ensureImageGenerationTool(body []byte) []byte {
+	tools := gjson.GetBytes(body, "tools")
+	if !tools.Exists() || !tools.IsArray() {
+		body, _ = sjson.SetRawBytes(body, "tools", imageGenToolArrayJSON)
+		return body
+	}
+	for _, t := range tools.Array() {
+		if t.Get("type").String() == "image_generation" {
+			return body
+		}
+	}
+	body, _ = sjson.SetRawBytes(body, "tools.-1", imageGenToolJSON)
+	return body
+}
+
 func isCodexModelCapacityError(errorBody []byte) bool {
 	if len(errorBody) == 0 {
 		return false
diff --git a/internal/runtime/executor/codex_executor_imagegen_test.go b/internal/runtime/executor/codex_executor_imagegen_test.go
new file mode 100644
index 000000000..43f42adee
--- /dev/null
+++ b/internal/runtime/executor/codex_executor_imagegen_test.go
@@ -0,0 +1,89 @@
+package executor
+
+import (
+	"testing"
+
+	"github.com/tidwall/gjson"
+)
+
+func TestEnsureImageGenerationTool_NoTools(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","input":"draw a cat"}`)
+	result := ensureImageGenerationTool(body)
+
+	tools := gjson.GetBytes(result, "tools")
+	if !tools.IsArray() {
+		t.Fatalf("expected tools array, got %v", tools.Type)
+	}
+	arr := tools.Array()
+	if len(arr) != 1 {
+		t.Fatalf("expected 1 tool, got %d", len(arr))
+	}
+	if arr[0].Get("type").String() != "image_generation" {
+		t.Fatalf("expected type=image_generation, got %s", arr[0].Get("type").String())
+	}
+	if arr[0].Get("output_format").String() != "png" {
+		t.Fatalf("expected output_format=png, got %s", arr[0].Get("output_format").String())
+	}
+}
+
+func TestEnsureImageGenerationTool_ExistingToolsWithoutImageGen(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","tools":[{"type":"function","name":"get_weather","parameters":{}}]}`)
+	result := ensureImageGenerationTool(body)
+
+	tools := gjson.GetBytes(result, "tools")
+	arr := tools.Array()
+	if len(arr) != 2 {
+		t.Fatalf("expected 2 tools, got %d", len(arr))
+	}
+	if arr[0].Get("type").String() != "function" {
+		t.Fatalf("expected first tool type=function, got %s", arr[0].Get("type").String())
+	}
+	if arr[1].Get("type").String() != "image_generation" {
+		t.Fatalf("expected second tool type=image_generation, got %s", arr[1].Get("type").String())
+	}
+}
+
+func TestEnsureImageGenerationTool_AlreadyPresent(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","tools":[{"type":"image_generation","output_format":"webp"},{"type":"function","name":"f1"}]}`)
+	result := ensureImageGenerationTool(body)
+
+	tools := gjson.GetBytes(result, "tools")
+	arr := tools.Array()
+	if len(arr) != 2 {
+		t.Fatalf("expected 2 tools (no duplicate), got %d", len(arr))
+	}
+	if arr[0].Get("output_format").String() != "webp" {
+		t.Fatalf("expected original output_format=webp preserved, got %s", arr[0].Get("output_format").String())
+	}
+}
+
+func TestEnsureImageGenerationTool_EmptyToolsArray(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","tools":[]}`)
+	result := ensureImageGenerationTool(body)
+
+	tools := gjson.GetBytes(result, "tools")
+	arr := tools.Array()
+	if len(arr) != 1 {
+		t.Fatalf("expected 1 tool, got %d", len(arr))
+	}
+	if arr[0].Get("type").String() != "image_generation" {
+		t.Fatalf("expected type=image_generation, got %s", arr[0].Get("type").String())
+	}
+}
+
+func TestEnsureImageGenerationTool_WebSearchAndImageGen(t *testing.T) {
+	body := []byte(`{"model":"gpt-5.4","tools":[{"type":"web_search"}]}`)
+	result := ensureImageGenerationTool(body)
+
+	tools := gjson.GetBytes(result, "tools")
+	arr := tools.Array()
+	if len(arr) != 2 {
+		t.Fatalf("expected 2 tools, got %d", len(arr))
+	}
+	if arr[0].Get("type").String() != "web_search" {
+		t.Fatalf("expected first tool type=web_search, got %s", arr[0].Get("type").String())
+	}
+	if arr[1].Get("type").String() != "image_generation" {
+		t.Fatalf("expected second tool type=image_generation, got %s", arr[1].Get("type").String())
+	}
+}