Human-in-the-Loop (HITL) Workflows

This guide covers Human-in-the-Loop (HITL) workflows, where execution pauses for external input.

Overview

HITL workflows use .wait() nodes to pause execution, allowing for human intervention or external decisions.

Basic Example

import { createFlow, FlowRuntime, ConsoleLogger } from 'flowcraft'

const flow = createFlow('approval-workflow')
	.node('start', () => ({ output: { user: 'Alice', amount: 1500 } }))
	.wait('wait-for-approval')
	.node('process', async ({ input }) => {
		if (input?.approved) {
			return { output: 'Approved' }
		}
		return { output: 'Denied' }
	})
	.edge('start', 'wait-for-approval')
	.edge('wait-for-approval', 'process')

const blueprint = flow.toBlueprint()
const functionRegistry = flow.getFunctionRegistry()
const runtime = new FlowRuntime({ logger: new ConsoleLogger() })

// Run until awaiting
const result = await runtime.run(blueprint, {}, { functionRegistry })
if (result.status === 'awaiting') {
	// Resume with input
	const finalResult = await runtime.resume(blueprint, result.serializedContext, { output: { approved: true } }, 'wait-for-approval')
	console.log(finalResult.context)
}

null

Press enter or space to select a node. You can then use the arrow keys to move the node around. You can then use the arrow keys to move the node around, press delete to remove it and press escape to cancel.

Press enter or space to select an edge. You can then press delete to remove it or press escape to cancel.

Key Concepts

• Wait Nodes: Pause execution.
• Resume: Provide input to continue.
• Status: Check result.status for 'awaiting'.

This pattern is useful for approvals, reviews, etc.