Add MCP JSON-RPC handlers and stdio fixes

Implement MCP JSON-RPC handling and related I/O fixes: mcploader now handles initialize, tools/list and tools/call (implements add_both_numbers) and returns JSON-RPC responses; stdio-server.send serializes object messages before writing; console logging on WScript now writes muted messages to StdErr; bump jsonrpc2 version to 0.1.7 and reformat extract(). These changes enable proper MCP capability negotiation, tool discovery and invocation over stdio.

app.js

@@ -48,6 +48,10 @@ var console = {
         if (this._muted) return;
         
         if (typeof WScript !== "undefined") {
+            if (this._muted) {
+                WScript.StdErr.WriteLine("[*] " + params.message);
+                return;
+            }
             WScript.StdOut.WriteLine("[*] " + params.message);
         }
     },

lib/jsonrpc2.js

@@ -108,7 +108,7 @@ exports.create = create;
 
 exports.DEFAULT_JSONRPC2_URL = DEFAULT_JSONRPC2_URL;
 
-exports.VERSIONINFO = "JSON-RPC 2.0 wrapper (jsonrpc2.js) version 0.1.6";
+exports.VERSIONINFO = "JSON-RPC 2.0 wrapper (jsonrpc2.js) version 0.1.7";
 exports.AUTHOR = "gnh1201@catswords.re.kr";
 exports.global = global;
 exports.require = global.require;

lib/stdio-server.js

@@ -16,6 +16,13 @@ function StdioServer() {
     };
     
     this.send = function (message) {
+        if (typeof message === "object") {
+            try {
+                var _serialized = JSON.stringify(message);
+                message = _serialized;
+            } catch (e) { /* ignore */ };
+        }
+        
         WScript.StdOut.WriteLine(message);
     };
     

mcploader.js

@@ -12,16 +12,70 @@ function main(args) {
     server.addEventListener("message", function(e) {
         var message = e.target.receive();
 
-		try {
+        e.target.send(
-			JsonRpc2.extract(message, function(method, params, id) {
+            JsonRpc2.extract(message, function (method, params, id) {
-				console.log("Received method: " + method);
+                if (method == "initialize") {
-			});
+                    return {
-		} catch (e) {
+                        "protocolVersion": "2025-11-25",
-			console.log("Ignored");
+                        "capabilities": {
+                            "extensions": {
+                                "io.modelcontextprotocol/ui": {
+                                    "mimeTypes": ["text/html;profile=mcp-app"]
+                                }
+                            }
+                        },
+                        "serverInfo": {
+                            "name": "WelsonJS MCP",
+                            "version": "1.0.0"
+                        }
+                    };
                 }
                 
-		// send message 
+                if (method == "tools/list") {
-		e.target.send("Hello world");
+                    return {
+                        "tools": [
+                            {
+                                "name": "add_both_numbers",
+                                "title": "add both_numbers (add A and B)",
+                                "description": "add two numbers (add A and B)",
+                                "inputSchema": {
+                                    "type": "object",
+                                    "properties": {
+                                        "a": {
+                                            "type": "number"
+                                        },
+                                        "b": {
+                                            "type": "number"
+                                        }
+                                    },
+                                    "required": ["a", "b"]
+                                }
+                            }
+                        ]
+                    };
+                }
+
+                if (method == "tools/call") {
+                    var function_calling_name = params.name;
+
+                    if (function_calling_name == "add_both_numbers") {
+                        return {
+                            "content": [
+                                {
+                                    "type": "text",
+                                    "text": "Result is " + (parseFloat(params.arguments.a) + parseFloat(params.arguments.b))
+                                }
+                            ],
+                            "isError": false
+                        };
+                    }
+                }
+
+                return {
+                    "isError": true
+                };
+            })
+        );
     });
 
     server.listen();