# The Final Bottleneck Historically, writing code was slower than reviewing code. It might not have felt that way, because code reviews sat in queues until someone got around to picking it up. But if you compare the actual acts themselves, creation was usually the more expensive part. In teams where people both wrote and reviewed code, it never felt like "we should probably program slower." So when more and more people tell me they no longer know what code is in their own codebase, I feel like something is very wrong here and it's time to reflect. ## You Are Here Software engineers often believe that [if we make the bathtub bigger](/2020/1/1/async-pressure/), overflow disappears. It doesn't. [OpenClaw](https://en.wikipedia.org/wiki/OpenClaw) right now has north of 2,500 pull requests open. That's a big bathtub. Anyone who has worked with queues knows this: if input grows faster than throughput, you have an accumulating failure. At that point, backpressure and load shedding are the only things that retain a system that can still operate. If you have ever been in a Starbucks overwhelmed by mobile orders, you know the feeling. The in-store experience breaks down. You no longer know how many orders are ahead of you. There is no clear line, no reliable wait estimate, and often no real cancellation path unless you escalate and make noise. That is what many AI-adjacent open source projects feel like right now. And increasingly, that is what a lot of internal company projects feel like in "AI-first" engineering teams, and that's not sustainable. You can't triage, you can't review, and many of the PRs cannot be merged after a certain point because they are too far out of date. And the creator might have lost the motivation to actually get it merged. There is huge excitement about newfound delivery speed, but in private conversations, I keep hearing the same second sentence: people are also confused about how to keep up with the pace they themselves created. ## We Have Been Here Before Humanity has been here before. Many times over. We already talk about the Luddites a lot in the context of AI, but it's interesting to see what led up to it. Mark Cartwright wrote a great [article about the textile industry](https://www.worldhistory.org/article/2183/the-textile-industry-in-the-british-industrial-rev/) in Britain during the industrial revolution. At its core was a simple idea: whenever a bottleneck was removed, innovation happened downstream from that. Weaving sped up? Yarn became the constraint. Faster spinning? Fibre needed to be improved to support the new speeds until finally the demand for cotton went up and that had to be automated too. We saw the same thing in shipping that led to modern automated ports and containerization. As software engineers we have been here too. Assembly did not scale to larger engineering teams, and we had to invent higher level languages. A lot of what programming languages and software development frameworks did was allow us to write code faster and to scale to larger code bases. What it did not do up to this point was take away the core skill of engineering. While it's definitely easier to write C than assembly, many of the core problems are the same. Memory latency still matters, physics are still our ultimate bottleneck, algorithmic complexity still makes or breaks software at scale. ## Giving Up? When one part of the pipeline becomes dramatically faster, you need to throttle input. [Pi](https://pi.dev/) is a great example of this. PRs are auto closed unless people are trusted. It takes [OSS vacations](https://x.com/badlogicgames/status/2021164603506368693). That's one option: you just throttle the inflow. You push against your newfound powers until you can handle them. ## Or Giving In But what if the speed continues to increase? What downstream of writing code do we have to speed up? Sure, the pull request review clearly turns into the bottleneck. But it cannot really be automated. If the machine writes the code, the machine better review the code at the same time. So what ultimately comes up for human review would already have passed the most critical possible review of the most capable machine. What else is in the way? If we continue with the fundamental belief that machines cannot be accountable, then humans need to be able to understand the output of the machine. And the machine will ship relentlessly. Support tickets of customers will go straight to machines to implement improvements and fixes, for other machines to review, for humans to rubber stamp in the morning. A lot of this sounds both unappealing and reminiscent of the textile industry. The individual weaver no longer carried responsibility for a bad piece of cloth. If it was bad, it became the responsibility of the factory as a whole and it was just replaced outright. As we're entering the phase of single-use plastic software, we might be moving the whole layer of responsibility elsewhere. ## I Am The Bottleneck But to me it still feels different. Maybe that's because my lowly brain can't comprehend the change we are going through, and future generations will just laugh about our challenges. It feels different to me, because what I see taking place in some Open Source projects, in some companies and teams feels deeply wrong and unsustainable. Even Steve Yegge himself now [casts doubts](https://steve-yegge.medium.com/the-ai-vampire-eda6e4f07163) about the sustainability of the ever-increasing pace of code creation. So what if we need to give in? What if we need to pave the way for this new type of engineering to become the standard? What affordances will we have to create to make it work? I for one do not know. I'm looking at this with fascination and bewilderment and trying to make sense of it. Because it is not the final bottleneck. We will find ways to take responsibility for what we ship, because society will demand it. Non-sentient machines will never be able to carry responsibility, and it looks like we will need to deal with this problem before machines achieve this status. Regardless of how [bizarre they appear to act](https://en.wikipedia.org/wiki/Moltbook) already. [I too am the bottleneck now](https://x.com/thorstenball/status/2022310010391302259). But you know what? Two years ago, I too was the bottleneck. I was the bottleneck all along. The machine did not really change that. And for as long as I carry responsibilities and am accountable, this will remain true. If we manage to push accountability upwards, it might change, but so far, how that would happen is not clear.