Basically this. My last several tickets were HITL coding with AI for several hours and then waiting 1-2 days while the code worked its way through PR and CI/CD process.

Coding speed was never really a bottleneck anywhere I have worked - it’s all the processes around it that take the most time and AI doesn’t help that much there.

True story; I wanted to make a tiny update to our CI / CD to upload copies of some artifacts to S3. It took 1min for the LLM to remind me of the correct syntax in aws cli to do the upload and the syntax to plug it into our GitHub Actions. It then took me the next 3 hours to figure out which IAMs needed to be updated in order to allow the upload before it was revealed that Actually uploading to the S3 requires the company IT to adjust bucket policies and this requires filing a ticket with IT and waiting 1-5 business days for a response then potentially having a call with them to discuss the change and justify why we need it. So now it's four days later and I still can't push to S3.

AI reduced this from a 5-day process to a 4.9-day process

I’m seeing it slightly differently. So much of our new slowdown is rework because we’ve seen a bunch more API and contract churn. The project I’m on has had more rework than I care to contemplate and most of it stems from everyone’s coding agents failing to stay synced up with each other on the details and their human handlers not noticing the discrepancies until we’re well into systems integration work.

If I may hijack your analogy, it would be like if all the construction crews got really fast at their work, so much so that the city decided to go for an “iterative construction” strategy because, in isolation, the cost of one team trying different designs on-site until they hit on one they liked became very small compared to the cost of getting city planners and civil engineers involved up-front. But what wasn’t considered was the rework multiplier effect that comes into play when the people building the water, sewage, electricity, telephones, roads, etc. are all repeatedly tweaking designs with minimal coordination amongst each other. So then those tweaks keep inducing additional design tweaks and rework on adjacent contractors because none of these design changes happen in a vacuum. Next thing you know all the houses are built but now need to be rewired because the electricity panel is designed for a different mains voltage from the drop and also it’s in the wrong part of the house because of a late change from overhead lines in the alleys to underground lines below the street.

Many have observed that coding agents lack object permanence so keeping them on a coherent plan requires giving them such a thoroughly documented plan up front. It actually has me wondering if optimal coding agent usage at scale resembles something of a return to waterfall (probably in more of a Royce sense than the bogeyman agile evangelists derived from the original idea) where the humans on the team mostly spend their time banging out systems specifications and testing protocols, and iteration on the spec becomes somewhat more removed from implementing it than it is in typical practice nowadays.