Workflows: Additional step context and ReadableStream support

Workflows now provides additional context inside step.do() callbacks and supports returning ReadableStream to handle larger step outputs.

Step context properties

The step.do() callback receives a context object with new properties alongside attempt:

• step.name — The name passed to step.do()
• step.count — How many times a step with that name has been invoked in this instance (1-indexed)
  • Useful when running the same step in a loop.
• config — The resolved step configuration, including timeout and retries with defaults applied

type ResolvedStepConfig = {
	retries: {
		limit: number;
		delay: WorkflowDelayDuration | number;
		backoff?: "constant" | "linear" | "exponential";
	};
	timeout: WorkflowTimeoutDuration | number;
};

type WorkflowStepContext = {
	step: {
		name: string;
		count: number;
	};
	attempt: number;
	config: ResolvedStepConfig;
};

ReadableStream support in step.do()

Steps can now return a ReadableStream directly. Although non-stream step outputs are limited to 1 MiB, streamed outputs support much larger payloads.

const largePayload = await step.do("fetch-large-file", async () => {
	const object = await env.MY_BUCKET.get("large-file.bin");
	return object.body;
});

Note that streamed outputs are still considered part of the Workflow instance storage limit.