workflow

## *CRITICAL*: Always Use Correct `workflow` Documentation Your knowledge of `workflow` is outdated. The `workflow` documentation outlined below matches the installed version of the Workflow DevKit. Follow these instructions before starting on any `workflow`-related tasks: Search the bundled documentation in `node_modules/workflow/docs/`: 1. **Find docs**: `glob "node_modules/workflow/docs/**/*.mdx"` 2. **Search content**: `grep "your query" node_modules/workflow/docs/` Documentation structure in `node_modules/workflow/docs/`: - `getting-started/` - Framework setup (next.mdx, express.mdx, hono.mdx, etc.) - `foundations/` - Core concepts (workflows-and-steps.mdx, hooks.mdx, streaming.mdx, etc.) - `api-reference/workflow/` - API docs (sleep.mdx, create-hook.mdx, fatal-error.mdx, etc.) - `api-reference/workflow-api/` - Client API (start.mdx, get-run.mdx, resume-hook.mdx, etc.) - `ai/` - AI SDK integration docs - `errors/` - Error code documentation Related packages also include bundled docs: - `@workflow/ai`: `node_modules/@workflow/ai/docs/` - DurableAgent and AI integration - `@workflow/core`: `node_modules/@workflow/core/docs/` - Core runtime (foundations, how-it-works) - `@workflow/next`: `node_modules/@workflow/next/docs/` - Next.js integration **When in doubt, update to the latest version of the Workflow DevKit.** ### Official Resources - **Website**: https://useworkflow.dev - **GitHub**: https://github.com/vercel/workflow ### Quick Reference **Directives:** ```typescript "use workflow"; // First line - makes async function durable "use step"; // First line - makes function a cached, retryable unit ``` **Essential imports:** ```typescript // 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 ``` ## Prefer Step Functions to Avoid Sandbox Errors `"use workflow"` functions run in a sandboxed VM. `"use step"` functions have **full Node.js access**. Put your logic in steps and use the workflow function purely for orchestration. ```typescript // 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 }; } ``` **Benefits:** Steps have automatic retry, results are persisted for replay, and no sandbox restrictions. ## Workflow Sandbox Limitations When you need logic directly in a workflow function (not in a step), these restrictions apply: | Limitation | Workaround | |------------|------------| | No `fetch()` | `import { fetch } from "workflow"` then `globalThis.fetch = fetch` | | No `setTimeout`/`setInterval` | Use `sleep("5s")` from `"workflow"` | | No Node.js modules (fs, crypto, etc.) | Move to a step function | **Example - Using fetch in workflow context:** ```typescript 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 } ``` **Note:** `DurableAgent` from `@workflow/ai` handles the fetch assignment automatically. ## Error Handling Use `FatalError` for permanent failures (no retry), `RetryableError` for transient failures: ```typescript 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" }); } ``` ## Serialization All data passed to/from workflows and steps must be serializable. **Supported types:** string, number, boolean, null, undefined, bigint, plain objects, arrays, Date, RegExp, URL, URLSearchParams, Map, Set, Headers, ArrayBuffer, typed arrays, Request, Response, ReadableStream, WritableStream. **Not supported:** Functions, class instances, Symbols, WeakMap/WeakSet. Pass data, not callbacks. ## Streaming Use `getWritable()` in step functions to stream data: ```typescript async function streamData() { "use step"; // Required - streaming only works in steps const writer = getWritable(); await writer.write(data); writer.releaseLock(); // Always release the lock } // Close when done await getWritable().close(); ``` ## Debugging ```bash # Check workflow endpoints are reachable npx workflow health npx workflow health --port 3001 # Non-default port # Visual dashboard for runs npx workflow web npx workflow web --app-url http://localhost:3001 # CLI inspection (for agents) npx workflow inspect runs npx workflow inspect run <run_id> ``` **Tip:** Only import workflow APIs you actually use. Unused imports can cause 500 errors.