diff --git a/backend/internal/service/openai_codex_transform_test.go b/backend/internal/service/openai_codex_transform_test.go
index be2d9777..106bcee8 100644
--- a/backend/internal/service/openai_codex_transform_test.go
+++ b/backend/internal/service/openai_codex_transform_test.go
@@ -8,7 +8,6 @@ import (
 
 func TestApplyCodexOAuthTransform_ToolContinuationPreservesInput(t *testing.T) {
 	// 续链场景：保留 item_reference 与 id，但不再强制 store=true。
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model": "gpt-5.2",
@@ -44,7 +43,6 @@ func TestApplyCodexOAuthTransform_ToolContinuationPreservesInput(t *testing.T) {
 
 func TestApplyCodexOAuthTransform_ExplicitStoreFalsePreserved(t *testing.T) {
 	// 续链场景：显式 store=false 不再强制为 true，保持 false。
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model": "gpt-5.1",
@@ -64,7 +62,6 @@ func TestApplyCodexOAuthTransform_ExplicitStoreFalsePreserved(t *testing.T) {
 
 func TestApplyCodexOAuthTransform_ExplicitStoreTrueForcedFalse(t *testing.T) {
 	// 显式 store=true 也会强制为 false。
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model": "gpt-5.1",
@@ -84,7 +81,6 @@ func TestApplyCodexOAuthTransform_ExplicitStoreTrueForcedFalse(t *testing.T) {
 
 func TestApplyCodexOAuthTransform_NonContinuationDefaultsStoreFalseAndStripsIDs(t *testing.T) {
 	// 非续链场景：未设置 store 时默认 false，并移除 input 中的 id。
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model": "gpt-5.1",
@@ -126,8 +122,6 @@ func TestFilterCodexInput_RemovesItemReferenceWhenNotPreserved(t *testing.T) {
 }
 
 func TestApplyCodexOAuthTransform_NormalizeCodexTools_PreservesResponsesFunctionTools(t *testing.T) {
-	setupCodexCache(t)
-
 	reqBody := map[string]any{
 		"model": "gpt-5.1",
 		"tools": []any{
@@ -158,7 +152,6 @@ func TestApplyCodexOAuthTransform_NormalizeCodexTools_PreservesResponsesFunction
 
 func TestApplyCodexOAuthTransform_EmptyInput(t *testing.T) {
 	// 空 input 应保持为空且不触发异常。
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model": "gpt-5.1",
@@ -185,13 +178,8 @@ func TestNormalizeCodexModel_Gpt53(t *testing.T) {
 	}
 }
 
-func setupCodexCache(t *testing.T) {
-	t.Helper()
-}
-
 func TestApplyCodexOAuthTransform_CodexCLI_PreservesExistingInstructions(t *testing.T) {
 	// Codex CLI 场景：已有 instructions 时不修改
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model":        "gpt-5.1",
@@ -209,7 +197,6 @@ func TestApplyCodexOAuthTransform_CodexCLI_PreservesExistingInstructions(t *test
 
 func TestApplyCodexOAuthTransform_CodexCLI_SuppliesDefaultWhenEmpty(t *testing.T) {
 	// Codex CLI 场景：无 instructions 时补充默认值
-	setupCodexCache(t)
 
 	reqBody := map[string]any{
 		"model": "gpt-5.1",
@@ -225,8 +212,7 @@ func TestApplyCodexOAuthTransform_CodexCLI_SuppliesDefaultWhenEmpty(t *testing.T
 }
 
 func TestApplyCodexOAuthTransform_NonCodexCLI_OverridesInstructions(t *testing.T) {
-	// 非 Codex CLI 场景：使用 opencode 指令覆盖
-	setupCodexCache(t)
+	// 非 Codex CLI 场景：使用内置 Codex CLI 指令覆盖
 
 	reqBody := map[string]any{
 		"model":        "gpt-5.1",