Link: The Coming Loop via Armin Ronacher
On his blog, Armin Ronacher shares his thoughts on the trend of applying “harness level loops” to coding. He has reservations but predicts the future of coding will be harness level loops and reflects on how we can retain the ability to understand and maintain code.
Over the last months I have watched more and more people build something on top of coding agents that feels meaningfully different from just using a coding agent. Some of this happens on top of Pi which is cool to see for sure! The pattern is the same everywhere though: work is put into a queue of sorts, a machine picks it up, attempts it, stops, and then some harness decides whether that was actually the end. If not, the harness continues the same session, injects another message, starts a fresh session with modified context, or sends the task to another machine. The task stays alive beyond the point where the model by itself would normally have said: “I am done.” There is already an agent loop inside every coding agent. The model calls a tool, incorporates the result, calls another tool, reads a file, edits a file, runs tests, and eventually produces some answer. That loop is one we have been quite familiar with for a long time. The other loop is the harness level loop: the loop outside the agent loop. That loop is also not new.
For now I have not moved past the point of comprehension being important to me. Given this desire, there is something I lack with my experience of code written without me paying attention, particularly from loops. Present-day models tend to produce code that is too defensive, too complex, too local in its reasoning. They avoid strong invariants. They add fallbacks instead of making bad states impossible. They duplicate code, invent bad abstractions, and paper over unclear design with more machinery. Worse though: I so far see very little progress of this improving. If anything, on that front it feels to me that we might even be making steps in the wrong direction
At the same time, it would be dishonest to pretend the loop pattern does not work because it already works astonishingly well in some domains. One thing that many of these [(porting code, performance explorations, security scanning)] have in common is that they either do not generate new code, but transform code that already exists, or they produce code that intentionally does not have a long shelf life. They either produce proof of concepts or ideas, surface findings or are more akin to mechnical transformation.
Not every line of code deserves human authorship and worse code might have been written in the past. But do I want all software to be authored this way? The same is true competitively as some teams will out-build others through raw speed. Some projects will suddenly move faster because a tiny group figures out how to orchestrate machines effectively. Some startups will do with five people what used to require fifty. Some people might literally put a machine against your product in a loop and ask it to “make it like the other one.” And if their users are happy, does it really matter? Not all software will be equally affected. Some domains will punish sloppiness and demand trust and responsibility, but a lot of software lives in a world where raw speed, quick experimentation, and vast coverage matter enormously.
If a codebase is produced by loops, reviewed by loops, patched by loops, and kept alive by loops, what happens when you no longer have access to the same class of systems? What happens when some trade restrictions take away access to the most powerful models? What if just the cost becomes unbearable? What if you and your team just lose the last remaining ability to understand the code without using the machine? We may create codebases that are not merely hard to maintain by humans, but that assume machine participation as part of their maintenance model. This is already happening! It’s not happening everywhere, and it might not even be happening in ways that are seen as problematic, but we see more and more of it.
Task queues for coding tasks, orchestration of agents, subagents, durable sessions will matter more and more. Even those of us who have their reservations and are not blindly embracing loops will have to start doing those experiments. We need to, because we need to understand how to make this future bounded and survivable. So I guess I’m coming to terms with that the question is not whether we will loop because clearly we will. Maybe the question is that in a future of loops, how do we don’t abdicate judgment, how we can retain rules of good engineering, how we can ensure that responsible human can continue to supervise, how we need to re-think how we architect code to retain sanity along the way.