diff --git a/backend/cmd/test_windsurf_minimal/main.go b/backend/cmd/test_windsurf_minimal/main.go
index fee6069e..7e936fbe 100644
--- a/backend/cmd/test_windsurf_minimal/main.go
+++ b/backend/cmd/test_windsurf_minimal/main.go
@@ -279,7 +279,7 @@ func main() {
 		// SendUserCascadeMessage
 		{
 			ctx, cancel := context.WithTimeout(context.Background(), f.timeout)
-			newCID, err := lsClient.SendUserCascadeMessage(ctx, f.jwt, cascadeID, f.prompt, pickedModel, "")
+			newCID, err := lsClient.SendUserCascadeMessage(ctx, f.jwt, cascadeID, f.prompt, pickedModel, "", 0)
 			if err == nil && newCID != "" {
 				cascadeID = newCID
 			}
diff --git a/backend/internal/pkg/windsurf/local_ls.go b/backend/internal/pkg/windsurf/local_ls.go
index 8a86df4f..29512efb 100644
--- a/backend/internal/pkg/windsurf/local_ls.go
+++ b/backend/internal/pkg/windsurf/local_ls.go
@@ -159,8 +159,11 @@ func (l *LocalLSClient) StartCascade(ctx context.Context, token string) (string,
 // SendUserCascadeMessage sends a message into an existing cascade session.
 // Returns the (possibly new) cascadeID — it changes if panel-state retry triggers a new StartCascade.
 // toolPreamble, if non-empty, is injected into the tool_calling_section override.
-func (l *LocalLSClient) SendUserCascadeMessage(ctx context.Context, token, cascadeID, text, modelUID, toolPreamble string) (string, error) {
+func (l *LocalLSClient) SendUserCascadeMessage(ctx context.Context, token, cascadeID, text, modelUID, toolPreamble string, modelEnumHint int) (string, error) {
 	modelEnum := resolveModelEnum(modelUID)
+	if modelEnum == 0 && modelEnumHint > 0 {
+		modelEnum = modelEnumHint
+	}
 
 	doSend := func(cid string) error {
 		body := encodeStringField(1, cid)
@@ -369,7 +372,7 @@ func (e *CascadeModelError) Error() string { return e.Msg }
 // StreamCascadeChat performs the full Cascade chat flow and returns accumulated text + thinking.
 // Includes cold/warm stall detection, step error handling, and final sweep (aligned with JS v1.9).
 // If reuseCascadeID is non-empty, skips StartCascade and reuses the existing cascade session.
-func (l *LocalLSClient) StreamCascadeChat(ctx context.Context, token, modelUID, userText, toolPreamble, reuseCascadeID string) (*CascadeChatResult, error) {
+func (l *LocalLSClient) StreamCascadeChat(ctx context.Context, token, modelUID, userText, toolPreamble, reuseCascadeID string, modelEnumHint int) (*CascadeChatResult, error) {
 	if err := l.WarmupCascade(ctx, token); err != nil {
 		return nil, fmt.Errorf("warmup: %w", err)
 	}
@@ -385,7 +388,7 @@ func (l *LocalLSClient) StreamCascadeChat(ctx context.Context, token, modelUID,
 		}
 	}
 
-	cascadeID, err = l.SendUserCascadeMessage(ctx, token, cascadeID, userText, modelUID, toolPreamble)
+	cascadeID, err = l.SendUserCascadeMessage(ctx, token, cascadeID, userText, modelUID, toolPreamble, modelEnumHint)
 	if err != nil {
 		return nil, fmt.Errorf("SendUserCascadeMessage: %w", err)
 	}
@@ -578,6 +581,17 @@ func (l *LocalLSClient) StreamCascadeChat(ctx context.Context, token, modelUID,
 		}
 	}
 
+	slog.Info("windsurf_cascade_poll_result",
+		"cascade_id", cascadeID[:min(8, len(cascadeID))],
+		"acc_text_len", len(accText),
+		"acc_thinking_len", len(accThinking),
+		"native_tool_calls", len(nativeToolCalls),
+		"saw_active", sawActive,
+		"saw_text", sawText,
+		"steps_seen", len(textCursors),
+		"idle_count", idleCount,
+	)
+
 	// Aggregate step usage
 	var aggUsage *StepUsage
 	for _, u := range usageByStep {
diff --git a/backend/internal/service/windsurf_chat_service.go b/backend/internal/service/windsurf_chat_service.go
index 0a6c5ba7..09507351 100644
--- a/backend/internal/service/windsurf_chat_service.go
+++ b/backend/internal/service/windsurf_chat_service.go
@@ -61,6 +61,10 @@ func (s *WindsurfChatService) Chat(ctx context.Context, req *WindsurfChatRequest
 	meta := windsurf.GetModelInfo(modelKey)
 
 	mode := s.resolveMode(meta)
+	// Tool emulation requires cascade mode for proto section injection
+	if mode == "legacy" && req.ToolPreamble != "" {
+		mode = "cascade"
+	}
 
 	var lease *windsurf.LSLease
 	if token.LSBinding.ContainerID != "" || token.LSBinding.ContainerName != "" {
@@ -109,8 +113,10 @@ func (s *WindsurfChatService) resolveMode(meta *windsurf.ModelMeta) string {
 
 func (s *WindsurfChatService) chatCascade(ctx context.Context, client *windsurf.LocalLSClient, apiKey string, meta *windsurf.ModelMeta, messages []windsurf.ChatMessage, toolPreamble string, modelKey string, lsEndpoint string) (*WindsurfChatResponse, error) {
 	modelUID := ""
+	modelEnumHint := 0
 	if meta != nil {
 		modelUID = meta.ModelUID
+		modelEnumHint = meta.EnumValue
 	}
 
 	fpBefore := windsurf.FingerprintBefore(messages, modelKey)
@@ -125,11 +131,11 @@ func (s *WindsurfChatService) chatCascade(ctx context.Context, client *windsurf.
 
 	userText := buildCascadeText(messages, modelUID, isResume)
 
-	result, err := client.StreamCascadeChat(ctx, apiKey, modelUID, userText, toolPreamble, reuseCascadeID)
+	result, err := client.StreamCascadeChat(ctx, apiKey, modelUID, userText, toolPreamble, reuseCascadeID, modelEnumHint)
 	if err != nil && isResume {
 		slog.Warn("windsurf_cascade_reuse_failed", "error", err, "model", modelKey)
 		userText = buildCascadeText(messages, modelUID, false)
-		result, err = client.StreamCascadeChat(ctx, apiKey, modelUID, userText, toolPreamble, "")
+		result, err = client.StreamCascadeChat(ctx, apiKey, modelUID, userText, toolPreamble, "", modelEnumHint)
 	}
 	if err != nil {
 		return nil, err
diff --git a/backend/internal/service/windsurf_gateway_service.go b/backend/internal/service/windsurf_gateway_service.go
index e6fd09ef..4e1fbd11 100644
--- a/backend/internal/service/windsurf_gateway_service.go
+++ b/backend/internal/service/windsurf_gateway_service.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/windsurf"
 
 	"github.com/gin-gonic/gin"
@@ -674,7 +675,7 @@ func windsurfExtractContentTextFromRaw(raw json.RawMessage) string {
 }
 
 func windsurfLogger(c *gin.Context, component string, fields ...zap.Field) *zap.Logger {
-	l := zap.L().With(zap.String("component", component))
+	l := logger.L().With(zap.String("component", component))
 	if c != nil {
 		if reqID := c.GetHeader("X-Request-ID"); reqID != "" {
 			l = l.With(zap.String("request_id", reqID))