Initialize SSE MCP Host

Dockerfile

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+FROM node:20-slim
+
+WORKDIR /app
+
+COPY package.json ./
+RUN npm install --production
+
+COPY index.js ./
+
+EXPOSE 7860
+ENV PORT=7860
+
+CMD ["node", "index.js"]

index.js

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+import express from "express";
+import { Server } from "@modelcontextprotocol/sdk/server/mcp.js";
+import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
+import { ListToolsRequestSchema, CallToolRequestSchema } from "@modelcontextprotocol/sdk/types.js";
+
+const app = express();
+const PORT = process.env.PORT || 7860;
+
+const server = new Server(
+  {
+    name: "mcp-cloud-host",
+    version: "1.0.0",
+  },
+  {
+    capabilities: {
+      tools: {},
+    },
+  }
+);
+
+// Define tools
+const calculateTool = {
+  name: "calculate",
+  description: "Evaluate a mathematical expression in JS safely",
+  inputSchema: {
+    type: "object",
+    properties: {
+      expression: {
+        type: "string",
+        description: "Math expression, e.g. 'Math.pow(2, 8) + 15'"
+      }
+    },
+    required: ["expression"]
+  }
+};
+
+server.setRequestHandler(ListToolsRequestSchema, async () => {
+  return {
+    tools: [calculateTool]
+  };
+});
+
+server.setRequestHandler(CallToolRequestSchema, async (request) => {
+  if (request.params.name === "calculate") {
+    const expr = request.params.arguments?.expression;
+    try {
+      if (/[^0-9\+\-\*\/\(\)\s\.\,Mathsqrtpow]/i.test(expr)) {
+        return {
+          content: [{ type: "text", text: "Error: Unauthorized characters in math expression" }],
+          isError: true
+        };
+      }
+      const result = Function(`"use strict"; return (${expr})`)();
+      return {
+        content: [{ type: "text", text: String(result) }]
+      };
+    } catch (e) {
+      return {
+        content: [{ type: "text", text: `Error: ${e.message}` }],
+        isError: true
+      };
+    }
+  }
+  throw new Error("Tool not found");
+});
+
+let transport = null;
+
+app.get("/sse", (req, res) => {
+  console.log("New SSE connection established");
+  transport = new SSEServerTransport("/messages", res);
+  server.connect(transport).catch(console.error);
+});
+
+app.post("/messages", express.json(), async (req, res) => {
+  if (transport) {
+    await transport.handlePostMessage(req, res);
+  } else {
+    res.status(400).send("No active SSE transport connection");
+  }
+});
+
+app.listen(PORT, () => {
+  console.log(`SSE MCP Host listening on port ${PORT}`);
+});

package.json

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+{
+  "name": "mcp-cloud-host",
+  "version": "1.0.0",
+  "description": "SSE MCP Host for 4-Space Architecture",
+  "main": "index.js",
+  "type": "module",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "@modelcontextprotocol/sdk": "^1.0.1",
+    "express": "^4.19.2"
+  }
+}