diff --git a/internal/translator/codex/openai/chat-completions/compat_test.go b/internal/translator/codex/openai/chat-completions/compat_test.go
new file mode 100644
index 00000000..9ae66727
--- /dev/null
+++ b/internal/translator/codex/openai/chat-completions/compat_test.go
@@ -0,0 +1,43 @@
+package chat_completions
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	responsesconverter "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/openai/openai/responses"
+	"github.com/tidwall/gjson"
+)
+
+func TestResponsesPayloadToolsArePreserved(t *testing.T) {
+	data, err := os.ReadFile("../../../../../error1.log")
+	if err != nil {
+		t.Fatalf("read log: %v", err)
+	}
+
+	var requestLine string
+	for _, line := range strings.Split(string(data), "\n") {
+		trimmed := strings.TrimSpace(line)
+		if strings.HasPrefix(trimmed, "{\"user\"") {
+			requestLine = trimmed
+			break
+		}
+	}
+	if requestLine == "" {
+		t.Fatalf("failed to extract request body from log")
+	}
+
+	raw := []byte(requestLine)
+	chatPayload := responsesconverter.ConvertOpenAIResponsesRequestToOpenAIChatCompletions("gpt-5.1-codex-max(xhigh)", raw, true)
+	codexPayload := ConvertOpenAIRequestToCodex("gpt-5.1-codex-max(xhigh)", chatPayload, true)
+
+	tools := gjson.GetBytes(codexPayload, "tools")
+	if !tools.IsArray() || len(tools.Array()) == 0 {
+		t.Fatalf("expected tools array, got: %s", tools.Raw)
+	}
+	for i, tool := range tools.Array() {
+		if name := strings.TrimSpace(tool.Get("name").String()); name == "" {
+			t.Fatalf("tool %d missing name after conversion: %s", i, tool.Raw)
+		}
+	}
+}
diff --git a/sdk/api/handlers/openai/openai_handlers.go b/sdk/api/handlers/openai/openai_handlers.go
index 485afe4d..ae925f91 100644
--- a/sdk/api/handlers/openai/openai_handlers.go
+++ b/sdk/api/handlers/openai/openai_handlers.go
@@ -17,6 +17,7 @@ import (
 	. "github.com/router-for-me/CLIProxyAPI/v6/internal/constant"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/interfaces"
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/registry"
+	responsesconverter "github.com/router-for-me/CLIProxyAPI/v6/internal/translator/openai/openai/responses"
 	"github.com/router-for-me/CLIProxyAPI/v6/sdk/api/handlers"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
@@ -109,7 +110,17 @@ func (h *OpenAIAPIHandler) ChatCompletions(c *gin.Context) {
 
 	// Check if the client requested a streaming response.
 	streamResult := gjson.GetBytes(rawJSON, "stream")
-	if streamResult.Type == gjson.True {
+	stream := streamResult.Type == gjson.True
+
+	// Some clients send OpenAI Responses-format payloads to /v1/chat/completions.
+	// Convert them to Chat Completions so downstream translators preserve tool metadata.
+	if shouldTreatAsResponsesFormat(rawJSON) {
+		modelName := gjson.GetBytes(rawJSON, "model").String()
+		rawJSON = responsesconverter.ConvertOpenAIResponsesRequestToOpenAIChatCompletions(modelName, rawJSON, stream)
+		stream = gjson.GetBytes(rawJSON, "stream").Bool()
+	}
+
+	if stream {
 		h.handleStreamingResponse(c, rawJSON)
 	} else {
 		h.handleNonStreamingResponse(c, rawJSON)
@@ -117,6 +128,21 @@ func (h *OpenAIAPIHandler) ChatCompletions(c *gin.Context) {
 
 }
 
+// shouldTreatAsResponsesFormat detects OpenAI Responses-style payloads that are
+// accidentally sent to the Chat Completions endpoint.
+func shouldTreatAsResponsesFormat(rawJSON []byte) bool {
+	if gjson.GetBytes(rawJSON, "messages").Exists() {
+		return false
+	}
+	if gjson.GetBytes(rawJSON, "input").Exists() {
+		return true
+	}
+	if gjson.GetBytes(rawJSON, "instructions").Exists() {
+		return true
+	}
+	return false
+}
+
 // Completions handles the /v1/completions endpoint.
 // It determines whether the request is for a streaming or non-streaming response
 // and calls the appropriate handler based on the model provider.