refactor: extract ResolveClaw402WalletKey to store layer and expand OKX margin mode tests

- Move duplicated claw402 wallet resolution logic into store.AIModelStore.ResolveClaw402WalletKey
- api/strategy.go and manager/trader_manager.go now delegate to the shared method
- Add detailed doc comment on OKX SetMarginMode explaining the local-state-only approach
  and why the legacy /api/v5/account/set-isolated-mode endpoint is not called
- Add 3 new test cases: cross mode leverage, OpenShort tdMode, SetTakeProfit tdMode

api/strategy.go

@@ -708,36 +708,5 @@ func (s *Server) runRealAITest(userID, modelID, systemPrompt, userPrompt string)
 }
 
 func (s *Server) resolveStrategyDataWalletKey(userID, selectedModelID string) (string, error) {
-	if selectedModelID != "" {
+	return s.store.AIModel().ResolveClaw402WalletKey(userID, selectedModelID)
-		model, err := s.store.AIModel().Get(userID, selectedModelID)
-		if err != nil {
-			return "", fmt.Errorf("failed to load selected AI model")
-		}
-
-		if model.Provider == "claw402" {
-			walletKey := string(model.APIKey)
-			if walletKey == "" {
-				return "", fmt.Errorf("selected claw402 model is missing wallet private key")
-			}
-			return walletKey, nil
-		}
-	}
-
-	models, err := s.store.AIModel().List(userID)
-	if err != nil {
-		return "", fmt.Errorf("failed to load AI models")
-	}
-
-	for _, model := range models {
-		if model == nil || model.Provider != "claw402" {
-			continue
-		}
-
-		walletKey := string(model.APIKey)
-		if walletKey != "" {
-			return walletKey, nil
-		}
-	}
-
-	return "", nil
 }

manager/trader_manager.go

@@ -744,6 +744,7 @@ func (tm *TraderManager) addTraderFromStore(traderCfg *store.Trader, aiModelCfg
 }
 
 func resolveTraderDataWalletKey(st *store.Store, userID string, selectedModel *store.AIModel) string {
+	// Fast path: selected model is itself a claw402 model.
 	if selectedModel != nil && selectedModel.Provider == "claw402" {
 		if walletKey := string(selectedModel.APIKey); walletKey != "" {
 			return walletKey
@@ -754,20 +755,14 @@ func resolveTraderDataWalletKey(st *store.Store, userID string, selectedModel *s
 		return ""
 	}
 
-	models, err := st.AIModel().List(userID)
+	// Fallback: find any configured claw402 model for this user so that paid
+	// NofxAI data sources work even when a non-claw402 model (e.g. deepseek) is
+	// selected as the AI brain.
+	preferredID := ""
+	walletKey, err := st.AIModel().ResolveClaw402WalletKey(userID, preferredID)
 	if err != nil {
 		logger.Warnf("⚠️ Failed to load claw402 wallet for trader data routing: %v", err)
 		return ""
 	}
-
+	return walletKey
-	for _, model := range models {
-		if model == nil || model.Provider != "claw402" {
-			continue
-		}
-		if walletKey := string(model.APIKey); walletKey != "" {
-			return walletKey
-		}
-	}
-
-	return ""
 }

store/ai_model.go

@@ -253,6 +253,43 @@ func (s *AIModelStore) Update(userID, id string, enabled bool, apiKey, customAPI
 }
 
 // Create creates an AI model
+// ResolveClaw402WalletKey returns the claw402 wallet private key for a user.
+// If preferredModelID is non-empty and points to a claw402 model, its key is returned first.
+// Otherwise the first enabled claw402 model in the user's model list is used.
+// Returns ("", nil) when no claw402 model is configured — callers should treat this as
+// "no paid data routing" rather than an error.
+func (s *AIModelStore) ResolveClaw402WalletKey(userID, preferredModelID string) (string, error) {
+	if preferredModelID != "" {
+		model, err := s.Get(userID, preferredModelID)
+		if err != nil {
+			return "", fmt.Errorf("failed to load selected AI model")
+		}
+		if model.Provider == "claw402" {
+			walletKey := string(model.APIKey)
+			if walletKey == "" {
+				return "", fmt.Errorf("selected claw402 model is missing wallet private key")
+			}
+			return walletKey, nil
+		}
+	}
+
+	models, err := s.List(userID)
+	if err != nil {
+		return "", fmt.Errorf("failed to load AI models")
+	}
+
+	for _, model := range models {
+		if model == nil || model.Provider != "claw402" {
+			continue
+		}
+		if walletKey := string(model.APIKey); walletKey != "" {
+			return walletKey, nil
+		}
+	}
+
+	return "", nil
+}
+
 func (s *AIModelStore) Create(userID, id, name, provider string, enabled bool, apiKey, customAPIURL string) error {
 	model := &AIModel{
 		ID:           id,

trader/okx/trader_account.go

@@ -80,7 +80,19 @@ func (t *OKXTrader) GetBalance() (map[string]interface{}, error) {
 	return result, nil
 }
 
-// SetMarginMode sets margin mode
+// SetMarginMode configures the margin mode (cross/isolated) that will be applied
+// to all subsequent leverage and order requests for this trader instance.
+//
+// OKX V5 unified accounts do not expose a per-symbol mode-switch endpoint that
+// works reliably — the legacy /api/v5/account/set-isolated-mode endpoint returns
+// error 51000 ("Parameter isoMode error") when called on a unified account.
+// Instead, OKX applies the mode per-request via the mgnMode field on
+// /api/v5/account/set-leverage and via the tdMode field on order placement.
+//
+// This implementation therefore stores the configured mode locally and injects it
+// into each subsequent API request, rather than making an API call here.
+// NOTE: unlike Binance/Bybit implementations of this interface, no network call
+// is made — the method only updates local state.
 func (t *OKXTrader) SetMarginMode(symbol string, isCrossMargin bool) error {
 	t.isCrossMargin = isCrossMargin
 	mgnMode := t.marginMode()

trader/okx/trader_margin_mode_test.go

@@ -188,3 +188,60 @@ func TestOKXPlaceLimitOrderUsesConfiguredMarginMode(t *testing.T) {
 		t.Fatalf("expected isolated tdMode, got %#v", orderRequests[0].Body["tdMode"])
 	}
 }
+
+func TestOKXCrossMarginModeUsedInLeverage(t *testing.T) {
+	rt := &recordingTransport{}
+	trader := newTestOKXTrader(rt, true) // cross margin
+
+	if err := trader.SetLeverage("BTCUSDT", 10); err != nil {
+		t.Fatalf("SetLeverage failed: %v", err)
+	}
+
+	leverageRequests := rt.requestsForPath(okxLeveragePath)
+	if len(leverageRequests) != 2 {
+		t.Fatalf("expected 2 leverage requests, got %d", len(leverageRequests))
+	}
+
+	for _, req := range leverageRequests {
+		if req.Body["mgnMode"] != "cross" {
+			t.Fatalf("expected cross leverage mode, got %#v", req.Body["mgnMode"])
+		}
+	}
+}
+
+func TestOKXOpenShortUsesConfiguredMarginMode(t *testing.T) {
+	rt := &recordingTransport{}
+	trader := newTestOKXTrader(rt, false) // isolated
+
+	if _, err := trader.OpenShort("BTCUSDT", 0.1, 5); err != nil {
+		t.Fatalf("OpenShort failed: %v", err)
+	}
+
+	orderRequests := rt.requestsForPath(okxOrderPath)
+	if len(orderRequests) == 0 {
+		t.Fatal("expected at least one order request")
+	}
+
+	lastOrder := orderRequests[len(orderRequests)-1]
+	if lastOrder.Body["tdMode"] != "isolated" {
+		t.Fatalf("expected isolated tdMode for OpenShort, got %#v", lastOrder.Body["tdMode"])
+	}
+}
+
+func TestOKXSetTakeProfitUsesConfiguredMarginMode(t *testing.T) {
+	rt := &recordingTransport{}
+	trader := newTestOKXTrader(rt, false) // isolated
+
+	if err := trader.SetTakeProfit("BTCUSDT", "LONG", 0.1, 100000); err != nil {
+		t.Fatalf("SetTakeProfit failed: %v", err)
+	}
+
+	algoRequests := rt.requestsForPath(okxAlgoOrderPath)
+	if len(algoRequests) != 1 {
+		t.Fatalf("expected 1 algo order request, got %d", len(algoRequests))
+	}
+
+	if algoRequests[0].Body["tdMode"] != "isolated" {
+		t.Fatalf("expected isolated tdMode for SetTakeProfit, got %#v", algoRequests[0].Body["tdMode"])
+	}
+}