fix: implement standard MCP protocol via @modelcontextprotocol/sdk

README.md

@@ -1 +1 @@
-# <https://forwardemail.net/mcp>
+# <https://forwardemail.net/mcp>

bin/mcp-server.js

@@ -2,4 +2,8 @@
 const {McpServer} = require('../lib/index.js');
 
 const server = new McpServer();
-server.listen();
+// eslint-disable-next-line unicorn/prefer-top-level-await
+server.listen().catch((error) => {
+  console.error('Server error:', error);
+  process.exit(1);
+});

lib/index.js

@@ -1,62 +1,66 @@
-const readline = require('node:readline');
+const {Server} = require('@modelcontextprotocol/sdk/server/index.js');
+const {
+  StdioServerTransport,
+} = require('@modelcontextprotocol/sdk/server/stdio.js');
+const {
+  ListToolsRequestSchema,
+  CallToolRequestSchema,
+} = require('@modelcontextprotocol/sdk/types.js');
+const {name, version} = require('../package.json');
 const {getTools} = require('./tools.js');
 
 class McpServer {
   constructor(options = {}) {
     this.tools = getTools(options);
-    this.rl = readline.createInterface({
-      input: process.stdin,
-      output: process.stdout,
-      terminal: false,
-    });
-  }
+    this.server = new Server({name, version}, {capabilities: {tools: {}}});
+
+    this.server.setRequestHandler(ListToolsRequestSchema, async () => ({
+      tools: Object.values(this.tools).map((tool) => ({
+        name: tool.toolSpec.name,
+        description: tool.toolSpec.description,
+        inputSchema: {
+          type: 'object',
+          properties: tool.toolSpec.input?.properties ?? {},
+        },
+      })),
+    }));
+
+    this.server.setRequestHandler(CallToolRequestSchema, async (request) => {
+      const toolName = request.params?.name;
+      const tool = this.tools[toolName];
+      if (!tool) {
+        return {
+          content: [{type: 'text', text: `Tool not found: ${toolName}`}],
+          isError: true,
+        };
+      }
 
-  listen() {
-    this.rl.on('line', async (line) => {
       try {
-        const request = JSON.parse(line);
-        await this.handleRequest(request);
+        const result = await tool.invoke(request.params?.arguments ?? {});
+        return {
+          content: [
+            {
+              type: 'text',
+              text:
+                typeof result === 'string'
+                  ? result
+                  : JSON.stringify(result, null, 2),
+            },
+          ],
+        };
       } catch (error) {
-        this.sendError(error.message);
+        const errorMessage = error.response?.data?.message || error.message;
+        return {
+          content: [{type: 'text', text: errorMessage}],
+          isError: true,
+        };
       }
     });
   }
 
-  async handleRequest(request) {
-    if (request.type === 'listTools') {
-      return this.sendResponse(request.id, {
-        tools: Object.values(this.tools).map((tool) => tool.toolSpec),
-      });
-    }
-
-    if (request.type === 'invokeTool') {
-      const tool = this.tools[request.name];
-      if (tool) {
-        try {
-          const result = await tool.invoke(request.arguments);
-          return this.sendResponse(request.id, {result});
-        } catch (error) {
-          const errorMessage = error.response?.data?.message || error.message;
-          return this.sendError(errorMessage, request.id);
-        }
-      }
-
-      return this.sendError(`Tool not found: ${request.name}`, request.id);
-    }
-
-    return this.sendError(`Unknown request type: ${request.type}`, request.id);
-  }
-
-  sendResponse(id, payload) {
-    this.send({type: 'toolResponse', id, ...payload});
-  }
-
-  sendError(message, id = null) {
-    this.send({type: 'error', id, message});
-  }
-
-  send(data) {
-    process.stdout.write(JSON.stringify(data) + '\n');
+  async listen() {
+    const transport = new StdioServerTransport();
+    await this.server.connect(transport);
   }
 }
 

package.json

@@ -10,6 +10,7 @@
     "url": "https://github.com/forwardemail/mcp-server/issues"
   },
   "dependencies": {
+    "@modelcontextprotocol/sdk": "^1.27.1",
     "axios": "^1.7.2"
   },
   "devDependencies": {