Add MCP smoke test client

scripts/mcp_smoke_test.mjs

@@ -0,0 +1,50 @@
+#!/usr/bin/env node
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+import { Client } from "@modelcontextprotocol/sdk/client/index.js";
+import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const repoRoot = path.resolve(__dirname, "..");
+
+async function main() {
+  const client = new Client({
+    name: "m2pack-smoke-test",
+    version: "0.1.0",
+  });
+
+  const transport = new StdioClientTransport({
+    command: "node",
+    args: [path.join(repoRoot, "mcp_server.mjs")],
+    cwd: repoRoot,
+    env: {
+      ...process.env,
+      M2PACK_BINARY: process.env.M2PACK_BINARY || path.join(repoRoot, "build", "m2pack"),
+    },
+    stderr: "inherit",
+  });
+
+  await client.connect(transport);
+
+  const tools = await client.listTools();
+  const binaryInfo = await client.callTool({
+    name: "pack_binary_info",
+    arguments: {},
+  });
+
+  console.log(JSON.stringify({
+    ok: true,
+    tool_count: tools.tools.length,
+    tool_names: tools.tools.map((tool) => tool.name),
+    binary_info: binaryInfo.structuredContent ?? null,
+  }, null, 2));
+
+  await transport.close();
+}
+
+main().catch((error) => {
+  console.error(error);
+  process.exit(1);
+});