nEngine/apps/editor/test/mcp-stdio.test.ts

import { existsSync } from "node:fs";
import { mkdtemp, rm } from "node:fs/promises";
import { tmpdir } from "node:os";
import { join, resolve } from "node:path";
import { describe, expect, it } from "vitest";
import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { StdioClientTransport } from "@modelcontextprotocol/sdk/client/stdio.js";
import { MCP_SERVER_NAME } from "../src/mcp-server.js";
import { newProject } from "../src/template.js";

const entry = resolve(process.cwd(), "dist/main/mcp-stdio.js");

function textOf(result: { content: { type: string; text?: string }[] }): string {
  return result.content.find((block) => block.type === "text")?.text ?? "";
}

describe("editor --mcp-stdio headless mode (spawned entry over stdio)", () => {
  it("spawns a drop-in stdio MCP server for --dir: handshake + full surface + a tool call", async () => {
    expect(existsSync(entry)).toBe(true);
    const dir = await mkdtemp(join(tmpdir(), "editor-stdio-"));
    try {
      const project = await newProject("Stdio Farm", dir);
      const client = new Client({ name: "editor-stdio-test", version: "0.0.1" });
      const transport = new StdioClientTransport({ command: "node", args: [entry, "--dir", project.root] });
      await client.connect(transport);
      try {
        expect(client.getServerVersion()).toMatchObject({ name: MCP_SERVER_NAME, version: "0.1.0" });
        const tools = await client.listTools();
        expect(tools.tools).toHaveLength(124);
        const info = JSON.parse(textOf(await client.callTool({ name: "server.info", arguments: {} }))) as {
          engine: string;
          content: { map: string[]; time: string[]; item: string[] };
        };
        expect(info.engine).toBe("nengine");
        expect(info.content.map).toEqual(["stdio-farm"]);
        expect(info.content.item.sort()).toEqual(["hoe", "stdio-farm", "stdio-farm-seed"]);
      } finally {
        await client.close();
      }
    } finally {
      await rm(dir, { recursive: true, force: true });
    }
  });

  it("item.create over stdio writes content into the project's content dir", async () => {
    expect(existsSync(entry)).toBe(true);
    const dir = await mkdtemp(join(tmpdir(), "editor-stdio-"));
    try {
      const project = await newProject("Stdio Farm", dir);
      const client = new Client({ name: "editor-stdio-test", version: "0.0.1" });
      const transport = new StdioClientTransport({ command: "node", args: [entry, "--dir", project.root] });
      await client.connect(transport);
      try {
        const created = await client.callTool({
          name: "item.create",
          arguments: { def: { id: "sickle", name: "Sickle", kind: "tool", stackable: false } },
        });
        expect(created.isError).not.toBe(true);
        const file = resolve(project.root, "content/items/sickle.yaml");
        expect(existsSync(file)).toBe(true);
      } finally {
        await client.close();
      }
    } finally {
      await rm(dir, { recursive: true, force: true });
    }
  });
});