Thanks for the detailed explanation — the use case is clear.
What you’re describing is synchronous webhook processing — keeping the HTTP connection open while the automation runs and returning the result inline. The reason the industry moved away from this is that automation processing time is unpredictable, and holding a connection open that long leads to timeouts and dropped requests. That’s why platforms like Stripe, GitHub, and Slack all use the same async model.
The standard pattern for your use case is: webhook triggers the automation → automation processes the data → POSTs the result back to your endpoint when complete. One extra step, but it’s the approach that holds up reliably in production.