workflow

Add "use workflow" as the first line of an async function to make it durable, and "use step" for functions needing full Node.js access. Orchestrate steps inside the workflow function and launch runs with start() from workflow/api.

Use createHook() inside the workflow with a deterministic token, then call resumeHook(token, data) from an API route to deliver the event. Hooks also implement AsyncIterable, so for await...of receives multiple events.

Workflow functions run in a sandboxed VM without fetch, setTimeout, or Node.js modules. Import fetch from "workflow" and assign globalThis.fetch, use sleep() instead of timers, or move the logic into a "use step" function.

Yes, DurableAgent from @workflow/ai/agent maintains agent state across interruptions and handles the sandbox fetch setup automatically. Tool execute functions needing Node.js access should use "use step", and getWritable() streams output.

Use the @workflow/vitest plugin for integration tests, with waitForHook and waitForSleep to reach pause points, then resumeHook or wakeUp to continue. Unit-test plain step functions directly without the plugin.

The sandbox blocks fetch, timers, and Node.js modules like fs and crypto, and all data crossing boundaries must be serializable. Class instances require the @workflow/serde protocol with static serialize methods defined inside the class body.