"use workflow";  // First line - makes async function durable
"use step";      // First line - makes function a cached, retryable unit

// Workflow primitives
import { sleep, fetch, createHook, createWebhook, getWritable } from "workflow";
import { FatalError, RetryableError } from "workflow";
import { getWorkflowMetadata, getStepMetadata } from "workflow";

// API operations
import { start, getRun, resumeHook, resumeWebhook } from "workflow/api";

// Framework integrations
import { withWorkflow } from "workflow/next";
import { workflow } from "workflow/vite";
import { workflow } from "workflow/astro";
// Or use modules: ["workflow/nitro"] for Nitro/Nuxt

// AI agent
import { DurableAgent } from "@workflow/ai/agent";

// Steps have full Node.js and npm access
async function fetchUserData(userId: string) {
  "use step";
  const response = await fetch(`https://api.example.com/users/${userId}`);
  return response.json();
}

async function processWithAI(data: any) {
  "use step";
  // AI SDK works in steps without workarounds
  return await generateText({
    model: openai("gpt-4"),
    prompt: `Process: ${JSON.stringify(data)}`,
  });
}

// Workflow orchestrates steps - no sandbox issues
export async function dataProcessingWorkflow(userId: string) {
  "use workflow";
  const data = await fetchUserData(userId);
  const processed = await processWithAI(data);
  return { success: true, processed };
}

import { fetch } from "workflow";

export async function myWorkflow() {
  "use workflow";
  globalThis.fetch = fetch;  // Required for AI SDK and HTTP libraries
  // Now generateText() and other libraries work
}

import { DurableAgent } from "@workflow/ai/agent";
import { getWritable } from "workflow";
import { z } from "zod";
import type { UIMessageChunk } from "ai";

async function lookupData({ query }: { query: string }) {
  "use step";
  // Step functions have full Node.js access
  return `Results for "${query}"`;
}

export async function myAgentWorkflow(userMessage: string) {
  "use workflow";

  const agent = new DurableAgent({
    model: "anthropic/claude-sonnet-4-5",
    system: "You are a helpful assistant.",
    tools: {
      lookupData: {
        description: "Search for information",
        inputSchema: z.object({ query: z.string() }),
        execute: lookupData,
      },
    },
  });

  const result = await agent.stream({
    messages: [{ role: "user", content: userMessage }],
    writable: getWritable<UIMessageChunk>(),
    maxSteps: 10,
  });

  return result.messages;
}

import { start } from "workflow/api";

// From an API route — works directly
export async function POST() {
  const run = await start(myWorkflow, [arg1, arg2]);
  return Response.json({ runId: run.runId });
}

// No-args workflow
const run = await start(noArgWorkflow);

import { start } from "workflow/api";

// Wrap start() in a step function
async function triggerChild(data: string) {
  "use step";
  const run = await start(childWorkflow, [data]);
  return run.runId;
}

export async function parentWorkflow() {
  "use workflow";
  const childRunId = await triggerChild("some data");  // Fire-and-forget via step
  await sleep("1h");
}

import { createHook } from "workflow";

export async function approvalWorkflow() {
  "use workflow";

  const hook = createHook<{ approved: boolean }>({
    token: "approval-123",  // deterministic token for external systems
  });

  const result = await hook;  // Workflow suspends here
  return result.approved;
}

import { createHook } from "workflow";

export async function chatWorkflow(channelId: string) {
  "use workflow";

  const hook = createHook<{ text: string; done?: boolean }>({
    token: `chat-${channelId}`,
  });

  for await (const event of hook) {
    await processMessage(event.text);
    if (event.done) break;
  }
}

import { resumeHook } from "workflow/api";

export async function POST(req: Request) {
  const { token, data } = await req.json();
  await resumeHook(token, data);
  return new Response("ok");
}

import { FatalError, RetryableError } from "workflow";

if (res.status >= 400 && res.status < 500) {
  throw new FatalError(`Client error: ${res.status}`);
}
if (res.status === 429) {
  throw new RetryableError("Rate limited", { retryAfter: "5m" });
}

import { getWritable } from "workflow";

export async function myWorkflow() {
  "use workflow";
  const writable = getWritable();
  await writeData(writable, "hello world");
}

async function writeData(writable: WritableStream, chunk: string) {
  "use step";
  const writer = writable.getWriter();
  try {
    await writer.write(chunk);
  } finally {
    writer.releaseLock();
  }
}

import { getWritable } from "workflow";

async function streamData(chunk: string) {
  "use step";
  const writer = getWritable().getWriter();
  try {
    await writer.write(chunk);
  } finally {
    writer.releaseLock();
  }
}

import { getWritable } from "workflow";

type LogEntry = { level: "debug" | "info" | "warn" | "error"; message: string; timestamp: number };
type AgentOutput = { type: "thought" | "action" | "result"; content: string };

async function logDebug(message: string) {
  "use step";
  const writer = getWritable<LogEntry>({ namespace: "logs:debug" }).getWriter();
  try {
    await writer.write({ level: "debug", message, timestamp: Date.now() });
  } finally {
    writer.releaseLock();
  }
}

async function logInfo(message: string) {
  "use step";
  const writer = getWritable<LogEntry>({ namespace: "logs:info" }).getWriter();
  try {
    await writer.write({ level: "info", message, timestamp: Date.now() });
  } finally {
    writer.releaseLock();
  }
}

async function emitAgentThought(thought: string) {
  "use step";
  const writer = getWritable<AgentOutput>({ namespace: "agent:thoughts" }).getWriter();
  try {
    await writer.write({ type: "thought", content: thought });
  } finally {
    writer.releaseLock();
  }
}

async function emitAgentResult(result: string) {
  "use step";
  // Important results go to the default stream for easy replay
  const writer = getWritable<AgentOutput>().getWriter();
  try {
    await writer.write({ type: "result", content: result });
  } finally {
    writer.releaseLock();
  }
}

export async function agentWorkflow(task: string) {
  "use workflow";
  
  await logInfo(`Starting task: ${task}`);
  await logDebug("Initializing agent context");
  await emitAgentThought("Analyzing the task requirements...");
  
  // ... agent processing ...
  
  await emitAgentResult("Task completed successfully");
  await logInfo("Workflow finished");
}

import { start, getRun } from "workflow/api";
import { agentWorkflow } from "./workflows/agent";

export async function POST(request: Request) {
  const run = await start(agentWorkflow, ["process data"]);

  // Access specific streams by namespace
  const results = run.getReadable({ namespace: undefined }); // Default stream (important results)
  const infoLogs = run.getReadable({ namespace: "logs:info" });
  const debugLogs = run.getReadable({ namespace: "logs:debug" });
  const thoughts = run.getReadable({ namespace: "agent:thoughts" });

  // Return only important results for most clients
  return new Response(results, { headers: { "Content-Type": "application/json" } });
}

// Resume from a specific point (useful for long sessions)
export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const runId = searchParams.get("runId")!;
  const startIndex = parseInt(searchParams.get("startIndex") || "0", 10);
  
  const run = getRun(runId);
  // Resume only the important stream, skip verbose debug logs
  const stream = run.getReadable({ startIndex });
  
  return new Response(stream);
}

undefined

**Debugging tips:**
- Use `--json` (`-j`) on any command for machine-readable output
- Use `--web` to open the Vercel Observability dashboard in your browser
- Use `--help` on any command for full usage details
- Only import workflow APIs you actually use. Unused imports can cause 500 errors.

import { describe, it, expect } from "vitest";
import { createUser } from "./user-signup";

describe("createUser step", () => {
  it("should create a user", async () => {
    const user = await createUser("test@example.com");
    expect(user.email).toBe("test@example.com");
  });
});

// vitest.integration.config.ts
import { defineConfig } from "vitest/config";
import { workflow } from "@workflow/vitest";

export default defineConfig({
  plugins: [workflow()],
  test: {
    include: ["**/*.integration.test.ts"],
    testTimeout: 60_000,
  },
});

// approval.integration.test.ts
import { describe, it, expect } from "vitest";
import { start, getRun, resumeHook } from "workflow/api";
import { waitForHook, waitForSleep } from "@workflow/vitest";
import { approvalWorkflow } from "./approval";

describe("approvalWorkflow", () => {
  it("should publish when approved", async () => {
    const run = await start(approvalWorkflow, ["doc-123"]);

    // Wait for the hook, then resume it
    await waitForHook(run, { token: "approval:doc-123" });
    await resumeHook("approval:doc-123", { approved: true, reviewer: "alice" });

    // Wait for sleep, then wake it up
    const sleepId = await waitForSleep(run);
    await getRun(run.runId).wakeUp({ correlationIds: [sleepId] });

    const result = await run.returnValue;
    expect(result).toEqual({ status: "published", reviewer: "alice" });
  });
});

import { start, resumeWebhook } from "workflow/api";
import { waitForHook } from "@workflow/vitest";

const run = await start(ingestWorkflow, ["ep-1"]);
const hook = await waitForHook(run);  // Discovers the random webhook token
await resumeWebhook(hook.token, new Request("https://example.com/webhook", {
  method: "POST",
  body: JSON.stringify({ event: "order.created" }),
}));