Another batch of MCP handlers ported

Plugins/BlueprintMCP/Source/BlueprintMCP/Private/BlueprintMCPHandlers_Mutation.cpp

@@ -459,219 +459,212 @@ void FBlueprintMCPServer::HandleDeleteAsset(const FJsonObject* Json, FJsonObject
 // HandleConnectPins — wire two pins together
 // ============================================================
 
-void FBlueprintMCPServer::HandleConnectPins(const FJsonObject* Json, FJsonObject* Result)
+// connect_pins is now handled by UMCPHandler_ConnectPins (new-style registry)
+
+void UMCPHandler_ConnectPins::Handle(const FJsonObject* Json, FJsonObject* Result)
 {
-	FString BlueprintName = Json->GetStringField(TEXT("blueprint"));
+	MCPHelper* Helper = MCPHelper::Get();
-	FString SourceNodeId = Json->GetStringField(TEXT("sourceNodeId"));
-	FString SourcePinName = Json->GetStringField(TEXT("sourcePinName"));
-	FString TargetNodeId = Json->GetStringField(TEXT("targetNodeId"));
-	FString TargetPinName = Json->GetStringField(TEXT("targetPinName"));
 
-	if (BlueprintName.IsEmpty() || SourceNodeId.IsEmpty() || SourcePinName.IsEmpty() ||
-		TargetNodeId.IsEmpty() || TargetPinName.IsEmpty())
-	{
-		return MakeErrorJson(Result, TEXT("Missing required fields: blueprint, sourceNodeId, sourcePinName, targetNodeId, targetPinName"));
-	}
-
-	// Load Blueprint
 	FString LoadError;
-	UBlueprint* BP = LoadBlueprintByName(BlueprintName, LoadError);
+	UBlueprint* BP = Helper->LoadBlueprintByName(Blueprint, LoadError);
 	if (!BP)
 	{
-		return MakeErrorJson(Result, LoadError);
+		return Helper->MakeErrorJson(Result, LoadError);
 	}
 
-	// Find source node
+	TArray<TSharedPtr<FJsonValue>> Results;
-	UEdGraph* SourceGraph = nullptr;
+	int32 SuccessCount = 0;
-	UEdGraphNode* SourceNode = FindNodeByGuid(BP, SourceNodeId, &SourceGraph);
-	if (!SourceNode)
-	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Source node '%s' not found"), *SourceNodeId));
-	}
 
-	// Find target node
+	for (const TSharedPtr<FJsonValue>& ConnVal : Connections.Array)
-	UEdGraphNode* TargetNode = FindNodeByGuid(BP, TargetNodeId);
-	if (!TargetNode)
 	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Target node '%s' not found"), *TargetNodeId));
+		TSharedRef<FJsonObject> EntryResult = MakeShared<FJsonObject>();
-	}
+		Results.Add(MakeShared<FJsonValueObject>(EntryResult));
 
-	// Find source pin
+		FConnectPinsEntry Entry;
-	UEdGraphPin* SourcePin = SourceNode->FindPin(FName(*SourcePinName));
+		FString PopulateError = Helper->PopulateFromJson(FConnectPinsEntry::StaticStruct(), &Entry, ConnVal);
-	if (!SourcePin)
+		if (!PopulateError.IsEmpty())
-	{
-		// List available pins for debugging
-		TArray<TSharedPtr<FJsonValue>> PinNames;
-		for (UEdGraphPin* P : SourceNode->Pins)
 		{
-			if (P) PinNames.Add(MakeShared<FJsonValueString>(
+			EntryResult->SetStringField(TEXT("error"), PopulateError);
-				FString::Printf(TEXT("%s (%s)"), *P->PinName.ToString(),
+			continue;
-					P->Direction == EGPD_Input ? TEXT("Input") : TEXT("Output"))));
 		}
-		MakeErrorJson(Result, FString::Printf(TEXT("Source pin '%s' not found on node '%s'"),
-			*SourcePinName, *SourceNodeId));
-		Result->SetArrayField(TEXT("availablePins"), PinNames);
-		return;
-	}
 
-	// Find target pin
+		EntryResult->SetStringField(TEXT("sourceNodeId"), Entry.SourceNodeId);
-	UEdGraphPin* TargetPin = TargetNode->FindPin(FName(*TargetPinName));
+		EntryResult->SetStringField(TEXT("sourcePinName"), Entry.SourcePinName);
-	if (!TargetPin)
+		EntryResult->SetStringField(TEXT("targetNodeId"), Entry.TargetNodeId);
-	{
+		EntryResult->SetStringField(TEXT("targetPinName"), Entry.TargetPinName);
-		// List available pins for debugging
+
-		TArray<TSharedPtr<FJsonValue>> PinNames;
+		UEdGraph* SourceGraph = nullptr;
-		for (UEdGraphPin* P : TargetNode->Pins)
+		UEdGraphNode* SourceNode = Helper->FindNodeByGuid(BP, Entry.SourceNodeId, &SourceGraph);
+		if (!SourceNode)
 		{
-			if (P) PinNames.Add(MakeShared<FJsonValueString>(
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Source node '%s' not found"), *Entry.SourceNodeId));
-				FString::Printf(TEXT("%s (%s)"), *P->PinName.ToString(),
+			continue;
-					P->Direction == EGPD_Input ? TEXT("Input") : TEXT("Output"))));
 		}
-		MakeErrorJson(Result, FString::Printf(TEXT("Target pin '%s' not found on node '%s'"),
+
-			*TargetPinName, *TargetNodeId));
+		UEdGraphNode* TargetNode = Helper->FindNodeByGuid(BP, Entry.TargetNodeId);
-		Result->SetArrayField(TEXT("availablePins"), PinNames);
+		if (!TargetNode)
-		return;
+		{
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Target node '%s' not found"), *Entry.TargetNodeId));
+			continue;
+		}
+
+		UEdGraphPin* SourcePin = SourceNode->FindPin(FName(*Entry.SourcePinName));
+		if (!SourcePin)
+		{
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Source pin '%s' not found on node '%s'"), *Entry.SourcePinName, *Entry.SourceNodeId));
+			continue;
+		}
+
+		UEdGraphPin* TargetPin = TargetNode->FindPin(FName(*Entry.TargetPinName));
+		if (!TargetPin)
+		{
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Target pin '%s' not found on node '%s'"), *Entry.TargetPinName, *Entry.TargetNodeId));
+			continue;
+		}
+
+		const UEdGraphSchema* Schema = SourceGraph->GetSchema();
+		if (!Schema)
+		{
+			EntryResult->SetStringField(TEXT("error"), TEXT("Graph schema not found"));
+			continue;
+		}
+
+		bool bConnected = Schema->TryCreateConnection(SourcePin, TargetPin);
+		if (!bConnected)
+		{
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(
+				TEXT("Cannot connect %s (%s) to %s (%s) — types are incompatible"),
+				*Entry.SourcePinName, *SourcePin->PinType.PinCategory.ToString(),
+				*Entry.TargetPinName, *TargetPin->PinType.PinCategory.ToString()));
+			continue;
+		}
+
+		EntryResult->SetBoolField(TEXT("success"), true);
+		SuccessCount++;
 	}
 
-	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Connecting %s.%s -> %s.%s"),
+	if (SuccessCount > 0)
-		*SourceNode->GetNodeTitle(ENodeTitleType::FullTitle).ToString(), *SourcePinName,
-		*TargetNode->GetNodeTitle(ENodeTitleType::FullTitle).ToString(), *TargetPinName);
-
-	// Try type-validated connection via the schema
-	const UEdGraphSchema* Schema = SourceGraph->GetSchema();
-	if (!Schema)
 	{
-		return MakeErrorJson(Result, TEXT("Graph schema not found"));
+		FBlueprintEditorUtils::MarkBlueprintAsModified(BP);
-	}
-	bool bConnected = Schema->TryCreateConnection(SourcePin, TargetPin);
-
-	Result->SetBoolField(TEXT("success"), bConnected);
-	Result->SetStringField(TEXT("blueprint"), BlueprintName);
-	Result->SetStringField(TEXT("sourcePinType"), SourcePin->PinType.PinCategory.ToString());
-	if (SourcePin->PinType.PinSubCategoryObject.IsValid())
-		Result->SetStringField(TEXT("sourcePinSubtype"), SourcePin->PinType.PinSubCategoryObject->GetName());
-	Result->SetStringField(TEXT("targetPinType"), TargetPin->PinType.PinCategory.ToString());
-	if (TargetPin->PinType.PinSubCategoryObject.IsValid())
-		Result->SetStringField(TEXT("targetPinSubtype"), TargetPin->PinType.PinSubCategoryObject->GetName());
-
-	if (!bConnected)
-	{
-		// Provide type mismatch details
-		FString Reason = FString::Printf(TEXT("Cannot connect %s (%s) to %s (%s) — types are incompatible"),
-			*SourcePinName, *SourcePin->PinType.PinCategory.ToString(),
-			*TargetPinName, *TargetPin->PinType.PinCategory.ToString());
-		return MakeErrorJson(Result, Reason);
 	}
 
-	// Save
+	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: ConnectPins — %d/%d succeeded in '%s'"),
-	bool bSaved = SaveBlueprintPackage(BP);
+		SuccessCount, Connections.Array.Num(), *Blueprint);
-	Result->SetBoolField(TEXT("saved"), bSaved);
 
-	// Return updated node state for both source and target
+	Result->SetBoolField(TEXT("success"), true);
-	TSharedPtr<FJsonObject> SourceNodeState = SerializeNode(SourceNode);
+	Result->SetStringField(TEXT("blueprint"), Blueprint);
-	TSharedPtr<FJsonObject> TargetNodeState = SerializeNode(TargetNode);
+	Result->SetNumberField(TEXT("successCount"), SuccessCount);
-	if (SourceNodeState.IsValid())
+	Result->SetNumberField(TEXT("totalCount"), Connections.Array.Num());
-		Result->SetObjectField(TEXT("updatedSourceNode"), SourceNodeState);
+	Result->SetArrayField(TEXT("results"), Results);
-	if (TargetNodeState.IsValid())
-		Result->SetObjectField(TEXT("updatedTargetNode"), TargetNodeState);
-
-	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Connection %s, save %s"),
-		bConnected ? TEXT("succeeded") : TEXT("failed"),
-		bSaved ? TEXT("succeeded") : TEXT("failed"));
 }
 
 // ============================================================
 // HandleDisconnectPin — break connections on a pin
 // ============================================================
 
-void FBlueprintMCPServer::HandleDisconnectPin(const FJsonObject* Json, FJsonObject* Result)
+// disconnect_pin is now handled by UMCPHandler_DisconnectPin (new-style registry)
+
+void UMCPHandler_DisconnectPin::Handle(const FJsonObject* Json, FJsonObject* Result)
 {
-	FString BlueprintName = Json->GetStringField(TEXT("blueprint"));
+	MCPHelper* Helper = MCPHelper::Get();
-	FString NodeId = Json->GetStringField(TEXT("nodeId"));
-	FString PinName = Json->GetStringField(TEXT("pinName"));
 
-	if (BlueprintName.IsEmpty() || NodeId.IsEmpty() || PinName.IsEmpty())
-	{
-		return MakeErrorJson(Result, TEXT("Missing required fields: blueprint, nodeId, pinName"));
-	}
-
-	// Optional: specific target to disconnect from
-	FString TargetNodeId = Json->GetStringField(TEXT("targetNodeId"));
-	FString TargetPinName = Json->GetStringField(TEXT("targetPinName"));
-
-	// Load Blueprint
 	FString LoadError;
-	UBlueprint* BP = LoadBlueprintByName(BlueprintName, LoadError);
+	UBlueprint* BP = Helper->LoadBlueprintByName(Blueprint, LoadError);
 	if (!BP)
 	{
-		return MakeErrorJson(Result, LoadError);
+		return Helper->MakeErrorJson(Result, LoadError);
 	}
 
-	// Find source node
+	TArray<TSharedPtr<FJsonValue>> Results;
-	UEdGraphNode* Node = FindNodeByGuid(BP, NodeId);
+	int32 SuccessCount = 0;
-	if (!Node)
+	int32 TotalDisconnected = 0;
-	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
-	}
 
-	// Find pin
+	for (const TSharedPtr<FJsonValue>& DiscVal : Disconnections.Array)
-	UEdGraphPin* Pin = Node->FindPin(FName(*PinName));
-	if (!Pin)
 	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Pin '%s' not found on node '%s'"), *PinName, *NodeId));
+		TSharedRef<FJsonObject> EntryResult = MakeShared<FJsonObject>();
-	}
+		Results.Add(MakeShared<FJsonValueObject>(EntryResult));
 
-	int32 DisconnectedCount = 0;
+		FDisconnectPinEntry Entry;
-
+		FString PopulateError = Helper->PopulateFromJson(FDisconnectPinEntry::StaticStruct(), &Entry, DiscVal);
-	if (!TargetNodeId.IsEmpty() && !TargetPinName.IsEmpty())
+		if (!PopulateError.IsEmpty())
-	{
-		// Disconnect a single specific link
-		UEdGraphNode* TargetNode = FindNodeByGuid(BP, TargetNodeId);
-		if (!TargetNode)
 		{
-			return MakeErrorJson(Result, FString::Printf(TEXT("Target node '%s' not found"), *TargetNodeId));
+			EntryResult->SetStringField(TEXT("error"), PopulateError);
+			continue;
 		}
 
-		UEdGraphPin* TargetPin = TargetNode->FindPin(FName(*TargetPinName));
+		EntryResult->SetStringField(TEXT("nodeId"), Entry.NodeId);
-		if (!TargetPin)
+		EntryResult->SetStringField(TEXT("pinName"), Entry.PinName);
+
+		UEdGraphNode* Node = Helper->FindNodeByGuid(BP, Entry.NodeId);
+		if (!Node)
 		{
-			return MakeErrorJson(Result, FString::Printf(TEXT("Target pin '%s' not found on node '%s'"),
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Node '%s' not found"), *Entry.NodeId));
-				*TargetPinName, *TargetNodeId));
+			continue;
 		}
 
-		if (Pin->LinkedTo.Contains(TargetPin))
+		UEdGraphPin* Pin = Node->FindPin(FName(*Entry.PinName));
+		if (!Pin)
 		{
+			EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Pin '%s' not found on node '%s'"), *Entry.PinName, *Entry.NodeId));
+			continue;
+		}
+
+		int32 DisconnectedCount = 0;
+
+		if (!Entry.TargetNodeId.IsEmpty() && !Entry.TargetPinName.IsEmpty())
+		{
+			UEdGraphNode* TargetNode = Helper->FindNodeByGuid(BP, Entry.TargetNodeId);
+			if (!TargetNode)
+			{
+				EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Target node '%s' not found"), *Entry.TargetNodeId));
+				continue;
+			}
+
+			UEdGraphPin* TargetPin = TargetNode->FindPin(FName(*Entry.TargetPinName));
+			if (!TargetPin)
+			{
+				EntryResult->SetStringField(TEXT("error"), FString::Printf(TEXT("Target pin '%s' not found on node '%s'"), *Entry.TargetPinName, *Entry.TargetNodeId));
+				continue;
+			}
+
+			if (!Pin->LinkedTo.Contains(TargetPin))
+			{
+				EntryResult->SetStringField(TEXT("error"), TEXT("The specified pins are not connected to each other"));
+				continue;
+			}
+
 			Pin->BreakLinkTo(TargetPin);
 			DisconnectedCount = 1;
 		}
 		else
 		{
-			return MakeErrorJson(Result, TEXT("The specified pins are not connected to each other"));
+			DisconnectedCount = Pin->LinkedTo.Num();
-		}
+			if (DisconnectedCount > 0)
-	}
+			{
-	else
+				Pin->BreakAllPinLinks(true);
-	{
+			}
-		// Disconnect all links on this pin
-		DisconnectedCount = Pin->LinkedTo.Num();
-		if (DisconnectedCount > 0)
-		{
-			Pin->BreakAllPinLinks(true);
 		}
+
+		EntryResult->SetBoolField(TEXT("success"), true);
+		EntryResult->SetNumberField(TEXT("disconnectedCount"), DisconnectedCount);
+		SuccessCount++;
+		TotalDisconnected += DisconnectedCount;
 	}
 
-	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Disconnected %d link(s) from %s.%s"),
+	if (TotalDisconnected > 0)
-		DisconnectedCount, *Node->GetNodeTitle(ENodeTitleType::FullTitle).ToString(), *PinName);
-
-	// Save
-	bool bSaved = false;
-	if (DisconnectedCount > 0)
 	{
-		bSaved = SaveBlueprintPackage(BP);
+		FBlueprintEditorUtils::MarkBlueprintAsModified(BP);
 	}
 
+	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: DisconnectPin — %d/%d succeeded, %d links broken in '%s'"),
+		SuccessCount, Disconnections.Array.Num(), TotalDisconnected, *Blueprint);
+
 	Result->SetBoolField(TEXT("success"), true);
-	Result->SetStringField(TEXT("blueprint"), BlueprintName);
+	Result->SetStringField(TEXT("blueprint"), Blueprint);
-	Result->SetNumberField(TEXT("disconnectedCount"), DisconnectedCount);
+	Result->SetNumberField(TEXT("successCount"), SuccessCount);
-	Result->SetBoolField(TEXT("saved"), bSaved);
+	Result->SetNumberField(TEXT("totalCount"), Disconnections.Array.Num());
+	Result->SetNumberField(TEXT("totalDisconnected"), TotalDisconnected);
+	Result->SetArrayField(TEXT("results"), Results);
 }
 
 // ============================================================
@@ -1128,34 +1121,28 @@ void FBlueprintMCPServer::HandleChangeStructNodeType(const FJsonObject* Json, FJ
 // HandleDeleteNode — remove a node from a blueprint graph
 // ============================================================
 
-void FBlueprintMCPServer::HandleDeleteNode(const FJsonObject* Json, FJsonObject* Result)
+// delete_node is now handled by UMCPHandler_DeleteNode (new-style registry)
+
+void UMCPHandler_DeleteNode::Handle(const FJsonObject* Json, FJsonObject* Result)
 {
-	FString BlueprintName = Json->GetStringField(TEXT("blueprint"));
+	MCPHelper* Helper = MCPHelper::Get();
-	FString NodeId = Json->GetStringField(TEXT("nodeId"));
 
-	if (BlueprintName.IsEmpty() || NodeId.IsEmpty())
-	{
-		return MakeErrorJson(Result, TEXT("Missing required fields: blueprint, nodeId"));
-	}
-
-	// Load Blueprint
 	FString LoadError;
-	UBlueprint* BP = LoadBlueprintByName(BlueprintName, LoadError);
+	UBlueprint* BP = Helper->LoadBlueprintByName(Blueprint, LoadError);
 	if (!BP)
 	{
-		return MakeErrorJson(Result, LoadError);
+		return Helper->MakeErrorJson(Result, LoadError);
 	}
 
-	// Find node
 	UEdGraph* Graph = nullptr;
-	UEdGraphNode* Node = FindNodeByGuid(BP, NodeId, &Graph);
+	UEdGraphNode* Node = Helper->FindNodeByGuid(BP, NodeId, &Graph);
 	if (!Node)
 	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
+		return Helper->MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
 	}
 	if (!Graph)
 	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Graph not found for node '%s'"), *NodeId));
+		return Helper->MakeErrorJson(Result, FString::Printf(TEXT("Graph not found for node '%s'"), *NodeId));
 	}
 
 	FString NodeClass = Node->GetClass()->GetName();
@@ -1167,7 +1154,7 @@ void FBlueprintMCPServer::HandleDeleteNode(const FJsonObject* Json, FJsonObject*
 	// without recreating the entire function/event.
 	if (Cast<UK2Node_FunctionEntry>(Node))
 	{
-		return MakeErrorJson(Result, FString::Printf(
+		return Helper->MakeErrorJson(Result, FString::Printf(
 			TEXT("Cannot delete FunctionEntry node '%s' in graph '%s'. ")
 			TEXT("This is the root node of the function — removing it would leave an empty, uncompilable graph. ")
 			TEXT("To remove the entire function, delete it from the Blueprint editor."),
@@ -1175,41 +1162,35 @@ void FBlueprintMCPServer::HandleDeleteNode(const FJsonObject* Json, FJsonObject*
 	}
 	if (Cast<UK2Node_Event>(Node))
 	{
-		return MakeErrorJson(Result, FString::Printf(
+		return Helper->MakeErrorJson(Result, FString::Printf(
 			TEXT("Cannot delete event entry node '%s' in graph '%s'. ")
 			TEXT("This is the root node of the event handler — removing it would leave an empty, uncompilable graph."),
 			*NodeTitle, *GraphName));
 	}
 	if (Cast<UK2Node_CustomEvent>(Node))
 	{
-		return MakeErrorJson(Result, FString::Printf(
+		return Helper->MakeErrorJson(Result, FString::Printf(
 			TEXT("Cannot delete CustomEvent entry node '%s' in graph '%s'. ")
 			TEXT("This is the root node of the custom event — removing it would leave an empty, uncompilable graph."),
 			*NodeTitle, *GraphName));
 	}
 
 	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Deleting node '%s' (%s) from graph '%s' in '%s'"),
-		*NodeId, *NodeTitle, *GraphName, *BlueprintName);
+		*NodeId, *NodeTitle, *GraphName, *Blueprint);
 
-	// Disconnect all pins
 	Node->BreakAllNodeLinks();
-
-	// Remove the node from the graph
 	Graph->RemoveNode(Node);
 
-	// Save (which also compiles)
+	FBlueprintEditorUtils::MarkBlueprintAsStructurallyModified(BP);
-	bool bSaved = SaveBlueprintPackage(BP);
 
-	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Node deleted, save %s"),
+	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Node deleted"));
-		bSaved ? TEXT("succeeded") : TEXT("failed"));
 
 	Result->SetBoolField(TEXT("success"), true);
-	Result->SetStringField(TEXT("blueprint"), BlueprintName);
+	Result->SetStringField(TEXT("blueprint"), Blueprint);
 	Result->SetStringField(TEXT("nodeId"), NodeId);
 	Result->SetStringField(TEXT("nodeClass"), NodeClass);
 	Result->SetStringField(TEXT("nodeTitle"), NodeTitle);
 	Result->SetStringField(TEXT("graph"), GraphName);
-	Result->SetBoolField(TEXT("saved"), bSaved);
 }
 
 // ============================================================
@@ -2221,31 +2202,27 @@ void UMCPHandler_DuplicateNodes::Handle(const FJsonObject* Json, FJsonObject* Re
 // HandleGetNodeComment — read a node's comment text
 // ============================================================
 
-void FBlueprintMCPServer::HandleGetNodeComment(const FJsonObject* Json, FJsonObject* Result)
+// get_node_comment is now handled by UMCPHandler_GetNodeComment (new-style registry)
-{
-	FString BlueprintName = Json->GetStringField(TEXT("blueprint"));
-	FString NodeId = Json->GetStringField(TEXT("nodeId"));
 
-	if (BlueprintName.IsEmpty() || NodeId.IsEmpty())
+void UMCPHandler_GetNodeComment::Handle(const FJsonObject* Json, FJsonObject* Result)
-	{
+{
-		return MakeErrorJson(Result, TEXT("Missing required fields: blueprint, nodeId"));
+	MCPHelper* Helper = MCPHelper::Get();
-	}
 
 	FString LoadError;
-	UBlueprint* BP = LoadBlueprintByName(BlueprintName, LoadError);
+	UBlueprint* BP = Helper->LoadBlueprintByName(Blueprint, LoadError);
 	if (!BP)
 	{
-		return MakeErrorJson(Result, LoadError);
+		return Helper->MakeErrorJson(Result, LoadError);
 	}
 
-	UEdGraphNode* Node = FindNodeByGuid(BP, NodeId);
+	UEdGraphNode* Node = Helper->FindNodeByGuid(BP, NodeId);
 	if (!Node)
 	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
+		return Helper->MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
 	}
 
 	Result->SetBoolField(TEXT("success"), true);
-	Result->SetStringField(TEXT("blueprint"), BlueprintName);
+	Result->SetStringField(TEXT("blueprint"), Blueprint);
 	Result->SetStringField(TEXT("nodeId"), NodeId);
 	Result->SetStringField(TEXT("comment"), Node->NodeComment);
 	Result->SetBoolField(TEXT("commentBubbleVisible"), Node->bCommentBubbleVisible);
@@ -2255,34 +2232,23 @@ void FBlueprintMCPServer::HandleGetNodeComment(const FJsonObject* Json, FJsonObj
 // HandleSetNodeComment — set a node's comment text
 // ============================================================
 
-void FBlueprintMCPServer::HandleSetNodeComment(const FJsonObject* Json, FJsonObject* Result)
+// set_node_comment is now handled by UMCPHandler_SetNodeComment (new-style registry)
+
+void UMCPHandler_SetNodeComment::Handle(const FJsonObject* Json, FJsonObject* Result)
 {
-	FString BlueprintName = Json->GetStringField(TEXT("blueprint"));
+	MCPHelper* Helper = MCPHelper::Get();
-	FString NodeId = Json->GetStringField(TEXT("nodeId"));
-
-	if (BlueprintName.IsEmpty() || NodeId.IsEmpty())
-	{
-		return MakeErrorJson(Result, TEXT("Missing required fields: blueprint, nodeId"));
-	}
-
-	if (!Json->HasField(TEXT("comment")))
-	{
-		return MakeErrorJson(Result, TEXT("Missing required field: comment"));
-	}
-
-	FString Comment = Json->GetStringField(TEXT("comment"));
 
 	FString LoadError;
-	UBlueprint* BP = LoadBlueprintByName(BlueprintName, LoadError);
+	UBlueprint* BP = Helper->LoadBlueprintByName(Blueprint, LoadError);
 	if (!BP)
 	{
-		return MakeErrorJson(Result, LoadError);
+		return Helper->MakeErrorJson(Result, LoadError);
 	}
 
-	UEdGraphNode* Node = FindNodeByGuid(BP, NodeId);
+	UEdGraphNode* Node = Helper->FindNodeByGuid(BP, NodeId);
 	if (!Node)
 	{
-		return MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
+		return Helper->MakeErrorJson(Result, FString::Printf(TEXT("Node '%s' not found"), *NodeId));
 	}
 
 	FString OldComment = Node->NodeComment;
@@ -2296,17 +2262,15 @@ void FBlueprintMCPServer::HandleSetNodeComment(const FJsonObject* Json, FJsonObj
 	}
 
 	FBlueprintEditorUtils::MarkBlueprintAsModified(BP);
-	bool bSaved = SaveBlueprintPackage(BP);
 
-	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Set comment on node '%s' in '%s', save %s"),
+	UE_LOG(LogTemp, Display, TEXT("BlueprintMCP: Set comment on node '%s' in '%s'"),
-		*NodeId, *BlueprintName, bSaved ? TEXT("succeeded") : TEXT("failed"));
+		*NodeId, *Blueprint);
 
 	Result->SetBoolField(TEXT("success"), true);
-	Result->SetStringField(TEXT("blueprint"), BlueprintName);
+	Result->SetStringField(TEXT("blueprint"), Blueprint);
 	Result->SetStringField(TEXT("nodeId"), NodeId);
 	Result->SetStringField(TEXT("oldComment"), OldComment);
 	Result->SetStringField(TEXT("newComment"), Comment);
-	Result->SetBoolField(TEXT("saved"), bSaved);
 }
 
 // ============================================================

Plugins/BlueprintMCP/Source/BlueprintMCP/Private/BlueprintMCPServer.cpp

@@ -611,9 +611,9 @@ bool FBlueprintMCPServer::Start(int32 InPort, bool bEditorMode)
 	Router->BindRoute(FHttpPath(TEXT("/api/test-save")), EHttpServerRequestVerbs::VERB_GET,
 		QueuedHandler(TEXT("testSave")));
 	Router->BindRoute(FHttpPath(TEXT("/api/connect-pins")), EHttpServerRequestVerbs::VERB_POST,
-		QueuedHandler(TEXT("connectPins")));
+		QueuedHandler(TEXT("connect_pins")));
 	Router->BindRoute(FHttpPath(TEXT("/api/disconnect-pin")), EHttpServerRequestVerbs::VERB_POST,
-		QueuedHandler(TEXT("disconnectPin")));
+		QueuedHandler(TEXT("disconnect_pin")));
 	Router->BindRoute(FHttpPath(TEXT("/api/refresh-all-nodes")), EHttpServerRequestVerbs::VERB_POST,
 		QueuedHandler(TEXT("refreshAllNodes")));
 	Router->BindRoute(FHttpPath(TEXT("/api/set-pin-default")), EHttpServerRequestVerbs::VERB_POST,
@@ -621,9 +621,9 @@ bool FBlueprintMCPServer::Start(int32 InPort, bool bEditorMode)
 	Router->BindRoute(FHttpPath(TEXT("/api/move-node")), EHttpServerRequestVerbs::VERB_POST,
 		QueuedHandler(TEXT("move_node")));
 	Router->BindRoute(FHttpPath(TEXT("/api/get-node-comment")), EHttpServerRequestVerbs::VERB_POST,
-		QueuedHandler(TEXT("getNodeComment")));
+		QueuedHandler(TEXT("get_node_comment")));
 	Router->BindRoute(FHttpPath(TEXT("/api/set-node-comment")), EHttpServerRequestVerbs::VERB_POST,
-		QueuedHandler(TEXT("setNodeComment")));
+		QueuedHandler(TEXT("set_node_comment")));
 	Router->BindRoute(FHttpPath(TEXT("/api/get-pin-info")), EHttpServerRequestVerbs::VERB_POST,
 		QueuedHandler(TEXT("getPinInfo")));
 	Router->BindRoute(FHttpPath(TEXT("/api/check-pin-compatibility")), EHttpServerRequestVerbs::VERB_POST,
@@ -639,7 +639,7 @@ bool FBlueprintMCPServer::Start(int32 InPort, bool bEditorMode)
 	Router->BindRoute(FHttpPath(TEXT("/api/remove-function-parameter")), EHttpServerRequestVerbs::VERB_POST,
 		QueuedHandler(TEXT("removeFunctionParameter")));
 	Router->BindRoute(FHttpPath(TEXT("/api/delete-node")), EHttpServerRequestVerbs::VERB_POST,
-		QueuedHandler(TEXT("deleteNode")));
+		QueuedHandler(TEXT("delete_node")));
 	Router->BindRoute(FHttpPath(TEXT("/api/duplicate-nodes")), EHttpServerRequestVerbs::VERB_POST,
 		QueuedHandler(TEXT("duplicate_nodes")));
 	Router->BindRoute(FHttpPath(TEXT("/api/search-by-type")), EHttpServerRequestVerbs::VERB_GET,
@@ -982,17 +982,17 @@ void FBlueprintMCPServer::RegisterHandlers()
 		TEXT("changeFunctionParamType"),
 		TEXT("removeFunctionParameter"),
 		TEXT("deleteAsset"),
-		TEXT("connectPins"),
+		TEXT("connect_pins"),
-		TEXT("disconnectPin"),
+		TEXT("disconnect_pin"),
 		TEXT("refreshAllNodes"),
 		TEXT("set_pin_default"),
 		TEXT("move_node"),
 		TEXT("changeStructNodeType"),
-		TEXT("deleteNode"),
+		TEXT("delete_node"),
 		TEXT("duplicate_nodes"),
 		TEXT("addNode"),
 		TEXT("spawn_node"),
-		TEXT("setNodeComment"),
+		TEXT("set_node_comment"),
 		TEXT("renameAsset"),
 		TEXT("reparentBlueprint"),
 		TEXT("setBlueprintDefault"),
@@ -1055,20 +1055,20 @@ void FBlueprintMCPServer::RegisterHandlers()
 	H(TEXT("changeFunctionParamType"),  &FBlueprintMCPServer::HandleChangeFunctionParamType);
 	H(TEXT("removeFunctionParameter"),  &FBlueprintMCPServer::HandleRemoveFunctionParameter);
 	H(TEXT("deleteAsset"),              &FBlueprintMCPServer::HandleDeleteAsset);
-	H(TEXT("connectPins"),              &FBlueprintMCPServer::HandleConnectPins);
+	// connect_pins is now handled by UMCPHandler_ConnectPins (new-style registry)
-	H(TEXT("disconnectPin"),            &FBlueprintMCPServer::HandleDisconnectPin);
+	// disconnect_pin is now handled by UMCPHandler_DisconnectPin (new-style registry)
 	H(TEXT("refreshAllNodes"),          &FBlueprintMCPServer::HandleRefreshAllNodes);
 	// set_pin_default is now handled by UMCPHandler_SetPinDefault (new-style registry)
 	// move_node is now handled by UMCPHandler_MoveNode (new-style registry)
-	H(TEXT("getNodeComment"),           &FBlueprintMCPServer::HandleGetNodeComment);
+	// get_node_comment is now handled by UMCPHandler_GetNodeComment (new-style registry)
-	H(TEXT("setNodeComment"),           &FBlueprintMCPServer::HandleSetNodeComment);
+	// set_node_comment is now handled by UMCPHandler_SetNodeComment (new-style registry)
 	H(TEXT("getPinInfo"),               &FBlueprintMCPServer::HandleGetPinInfo);
 	H(TEXT("checkPinCompatibility"),    &FBlueprintMCPServer::HandleCheckPinCompatibility);
 	H(TEXT("listClasses"),              &FBlueprintMCPServer::HandleListClasses);
 	H(TEXT("listFunctions"),            &FBlueprintMCPServer::HandleListFunctions);
 	H(TEXT("listProperties"),           &FBlueprintMCPServer::HandleListProperties);
 	H(TEXT("changeStructNodeType"),     &FBlueprintMCPServer::HandleChangeStructNodeType);
-	H(TEXT("deleteNode"),               &FBlueprintMCPServer::HandleDeleteNode);
+	// delete_node is now handled by UMCPHandler_DeleteNode (new-style registry)
 	// duplicate_nodes is now handled by UMCPHandler_DuplicateNodes (new-style registry)
 	H(TEXT("validateBlueprint"),        &FBlueprintMCPServer::HandleValidateBlueprint);
 	H(TEXT("validateAllBlueprints"),    &FBlueprintMCPServer::HandleValidateAllBlueprints);

Plugins/BlueprintMCP/Source/BlueprintMCP/Public/BlueprintMCPHandlers_Mutation.h

@@ -144,3 +144,144 @@ public:
 
 	virtual void Handle(const FJsonObject* Json, FJsonObject* Result) override;
 };
+
+UCLASS(meta=(ToolName="get_node_comment"))
+class UMCPHandler_GetNodeComment : public UMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Blueprint name or package path"))
+	FString Blueprint;
+
+	UPROPERTY(meta=(Description="Node GUID"))
+	FString NodeId;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Get the comment text and bubble visibility of a node.");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FJsonObject* Result) override;
+};
+
+UCLASS(meta=(ToolName="set_node_comment"))
+class UMCPHandler_SetNodeComment : public UMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Blueprint name or package path"))
+	FString Blueprint;
+
+	UPROPERTY(meta=(Description="Node GUID"))
+	FString NodeId;
+
+	UPROPERTY(meta=(Description="Comment text to set"))
+	FString Comment;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Set a node's comment text. Makes the comment bubble visible if non-empty.");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FJsonObject* Result) override;
+};
+
+UCLASS(meta=(ToolName="delete_node"))
+class UMCPHandler_DeleteNode : public UMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Blueprint name or package path"))
+	FString Blueprint;
+
+	UPROPERTY(meta=(Description="Node GUID"))
+	FString NodeId;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Delete a node from a Blueprint graph. "
+			"Cannot delete entry nodes (FunctionEntry, Event, CustomEvent).");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FJsonObject* Result) override;
+};
+
+USTRUCT()
+struct FConnectPinsEntry
+{
+	GENERATED_BODY()
+
+	UPROPERTY()
+	FString SourceNodeId;
+
+	UPROPERTY()
+	FString SourcePinName;
+
+	UPROPERTY()
+	FString TargetNodeId;
+
+	UPROPERTY()
+	FString TargetPinName;
+};
+
+UCLASS(meta=(ToolName="connect_pins"))
+class UMCPHandler_ConnectPins : public UMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Blueprint name or package path"))
+	FString Blueprint;
+
+	UPROPERTY(meta=(Description="Array of {sourceNodeId, sourcePinName, targetNodeId, targetPinName} objects"))
+	FMCPJsonArray Connections;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Connect pins between nodes in a Blueprint graph.");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FJsonObject* Result) override;
+};
+
+USTRUCT()
+struct FDisconnectPinEntry
+{
+	GENERATED_BODY()
+
+	UPROPERTY()
+	FString NodeId;
+
+	UPROPERTY()
+	FString PinName;
+
+	UPROPERTY(meta=(Optional))
+	FString TargetNodeId;
+
+	UPROPERTY(meta=(Optional))
+	FString TargetPinName;
+};
+
+UCLASS(meta=(ToolName="disconnect_pin"))
+class UMCPHandler_DisconnectPin : public UMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Description="Blueprint name or package path"))
+	FString Blueprint;
+
+	UPROPERTY(meta=(Description="Array of {nodeId, pinName, targetNodeId?, targetPinName?} objects. If target is omitted, all connections on the pin are broken."))
+	FMCPJsonArray Disconnections;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Disconnect pins in a Blueprint graph. "
+			"Can disconnect a specific link or all links on a pin.");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FJsonObject* Result) override;
+};

Plugins/BlueprintMCP/Source/BlueprintMCP/Public/BlueprintMCPServer.h

@@ -141,7 +141,6 @@ private:
 	void HandleChangeFunctionParamType(const FJsonObject* Json, FJsonObject* Result);
 	void HandleRemoveFunctionParameter(const FJsonObject* Json, FJsonObject* Result);
 	void HandleDeleteAsset(const FJsonObject* Json, FJsonObject* Result);
-	void HandleDeleteNode(const FJsonObject* Json, FJsonObject* Result);
 	void HandleAddNode(const FJsonObject* Json, FJsonObject* Result);
 	void HandleRenameAsset(const FJsonObject* Json, FJsonObject* Result);
 
@@ -150,11 +149,7 @@ private:
 	void HandleValidateAllBlueprints(const FJsonObject* Json, FJsonObject* Result);
 
 	// ----- Pin manipulation (write) -----
-	void HandleConnectPins(const FJsonObject* Json, FJsonObject* Result);
-	void HandleDisconnectPin(const FJsonObject* Json, FJsonObject* Result);
 	void HandleRefreshAllNodes(const FJsonObject* Json, FJsonObject* Result);
-	void HandleGetNodeComment(const FJsonObject* Json, FJsonObject* Result);
-	void HandleSetNodeComment(const FJsonObject* Json, FJsonObject* Result);
 
 	// ----- Pin introspection (read-only) -----
 	void HandleGetPinInfo(const FJsonObject* Json, FJsonObject* Result);