import { z } from "zod";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { JsonFileSessionStore, withTasks, withFileTransfer, asToolRegistrar } from "mcp-longjobs";

const mcp = new McpServer({ name: "my-server", version: "1.0.0" });
const registrar = asToolRegistrar(mcp);
const store = new JsonFileSessionStore("./state/sessions.json");

const tasks = withTasks(registrar, { store });

tasks.taskTool("crawl-site", {
  description: "Crawl a site and produce a report (takes minutes)",
  inputSchema: { url: z.string(), maxPages: z.number().default(50) },
}, async (args, ctx) => {
  for (const page of pages) {
    if (ctx.signal.aborted) throw new Error("cancelled");
    await ctx.progress(`Crawled ${page.url}`, done / total);

    if (needsConfirmation(page)) {
      const answer = await ctx.needInput({ prompt: `Include ${page.url}?`, choices: ["yes", "no"] });
      if (answer === "no") continue;
    }
  }
  return { summary, reportPath }; // small result for the model; big artifacts go through file transfer
});

withFileTransfer(registrar, { store, storageDir: "./state/blobs" });

{
  "status": "failed",
  "error": {
    "code": "offset_mismatch",
    "message": "Expected offset 131072, got 0.",
    "retryable": true,
    "recoveryHint": "Do NOT resend the whole file. Re-send this chunk starting at offset 131072.",
    "partial": { "cursor": 131072 }
  }
}

git clone https://github.com/ljppanda/mcp-longjobs
cd mcp-longjobs
npm install && npm run build
node dist/examples/report-generator.js

{
  "mcpServers": {
    "report-generator": {
      "command": "node",
      "args": ["/absolute/path/to/mcp-longjobs/dist/examples/report-generator.js"]
    }
  }
}

npm install
npm test         # vitest
npm run build    # tsc -> dist/
npm run example  # build + run the demo server