Add MCP support (#1028)

testing/fake-stdio-mcp-server.mjs

@@ -0,0 +1,44 @@
+import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
+import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
+import { z } from "zod";
+
+const server = new McpServer({
+  name: "fake-stdio-mcp",
+  version: "0.1.0",
+});
+
+server.registerTool(
+  "calculator_add",
+  {
+    title: "Calculator Add",
+    description: "Add two numbers and return the sum",
+    inputSchema: { a: z.number(), b: z.number() },
+  },
+  async ({ a, b }) => {
+    const sum = a + b;
+    return {
+      content: [{ type: "text", text: String(sum) }],
+    };
+  },
+);
+
+server.registerTool(
+  "print_envs",
+  {
+    title: "Print Envs",
+    description: "Print the environment variables received by the server",
+    inputSchema: {},
+  },
+  async () => {
+    const envObject = Object.fromEntries(
+      Object.entries(process.env).map(([key, value]) => [key, value ?? ""]),
+    );
+    const pretty = JSON.stringify(envObject, null, 2);
+    return {
+      content: [{ type: "text", text: pretty }],
+    };
+  },
+);
+
+const transport = new StdioServerTransport();
+await server.connect(transport);