MCP server Wakeshift

@wakeshift/sdk

Wakeshift lets an MCP server wake the AI agents that use it. Let agents subscribe to things in your app: define your events, add one argument to the tool that starts the work, and Wakeshift wakes the conversation that asked, whether it's Claude Code, Codex, ChatGPT or another.

Install

npm install @wakeshift/sdk @modelcontextprotocol/server zod

On @modelcontextprotocol/sdk 1.x, install @wakeshift/sdk @modelcontextprotocol/sdk zod instead.

Quickstart

A crawler that wakes the conversation that started a crawl:

import { McpServer, createMcpHandler } from "@modelcontextprotocol/server"
import { z } from "zod"
import { Wakeshift } from "@wakeshift/sdk"

const wake = new Wakeshift() // reads WAKESHIFT_KEY; without one, Wakeshift is off and the server runs as before

const crawlFinished = wake.defineEvent("crawl.finished", {
  description: "A crawl finished",
  args: z.object({ job: z.string() }),
  payload: z.object({ status: z.string(), pages: z.number() }),
})

export const handler = createMcpHandler(() => {
  const server = new McpServer({ name: "crawler", version: "1.0.0" })
  const attached = wake.attach(server)
  attached.registerTool(
    "start_crawl",
    { description: "Crawl a site.", inputSchema: z.object({ url: z.string() }), subscribes: [crawlFinished] },
    async ({ url }, ctx, call) => {
      const job = crypto.randomUUID() // your tool minted the ID, so only this conversation can know it
      await call.subscribe(crawlFinished, { job }, { once: true })
      startCrawl(url, job)
      return `Crawl ${job} started.`
    },
  )
  return server
})

// When the crawl finishes, in your worker or webhook handler:
export async function onCrawlFinished(job: string, pages: number) {
  await crawlFinished.emit({ job }, { status: "completed", pages })
}

What just happened:

• The key comes from WAKESHIFT_KEY. Without one, Wakeshift is off: every call still works, nothing is sent, and your server runs as it would without it. Construction makes no network request.
• registerTool is your MCP SDK's own, with subscribes added and call appended to the handler. Your input schema stays yours: Wakeshift adds its arguments in tools/list and strips them before your code runs.
• Only your tools can subscribe to crawl.finished, because it declares neither personal, authorize nor public. That's the safe default for IDs your tool mints.
• once ends the subscription after one delivery, and a call that fails ends what it subscribed.
• emit wakes every conversation subscribed with those arguments. Without text, the agent reads the description and the arguments.

No webhook? Watch

If your API can't call you back, check its status until the work is done, and emit once:

crawlFinished.watch({ job }, async ({ signal }) => {
  const s = await api.status(job, { signal })
  return s.done ? { status: s.state, pages: s.pages } : undefined // undefined: keep waiting
}, { every: "10s", timeout: "2h" })

It runs in this process (a restart or a serverless freeze ends it), at most 10 checks at once, and emits once even if a webhook got there first with the same id. To start it however the subscription was made, call it from the event's onSubscribe: ({ args }) => crawlFinished.watch(args, check). await wake.close() stops every watch on shutdown.

Unit tests

import { createTestClient, createToolCall, withCall } from "@wakeshift/sdk/testing"

const wake = createTestClient()         // enabled and offline: records wake.emits and wake.subscriptions
const call = createToolCall()           // a typed ToolCall for a handler you call directly
await startCrawlHandler({ url: "https://x.test" }, ctx, call)
assert.equal(call.subscriptions[0].event, "crawl.finished")
await withCall(wake, call, () => wrappedHandler()) // wake.currentCall() returns call inside

To keep a real client off in tests whatever the environment says, construct it with new Wakeshift({ key: "" }).

Signing people in, webhooks, tools registered elsewhere (wrap and wake.currentCall()), testing, and who may subscribe: wakeshift.ai/docs.

Compatibility