Context is the bottleneck for coding agents now

IMHO, jumping from Level 2 to Level 5 is a matter of:

- Better structured codebases - we need hierarchical codebases with minimal depth, maximal orthogonality and reasonable width. Think microservices.

- Better documentation - most code documentations are not built to handle updates. We need a proper graph structure with few sources of truth that get propagated downstream. Again, some optimal sort of hierarchy is crucial here.

At this point, I really don't think that we necessarily need better agents.

Setup your codebase optimally, spin up 5-10 instances of gpt-5-codex-high for each issue/feature/refactor (pick the best according to some criteria) and your life will go smoothly

> Think microservices.

Microservices should already be a last resort when you’ve either: a) hit technical scale that necessitates it b) hit organizational complexity that necessitates it

Opting to introduce them sooner will almost certainly increase the complexity of your codebase prematurely (already a hallmark of LLM development).

> Better documentation

If this means reasoning as to why decisions are made then yes. If this means explaining the code then no - code is the best documentation. English is nowhere near as good at describing how to interface with computers.

Given how long gpt codex 5 has been out, there’s no way you’ve followed these practices for a reasonable enough time to consider them definitive (2 years at the least, likely much longer).

> Opting to introduce them sooner will almost certainly increase the complexity of your codebase prematurely

Agreed, but how else are you going to scale mostly AI written code? Relying mostly on AI agents gives you that organizational complexity.

> Given how long gpt codex 5 has been out, there’s no way you’ve followed these practices for a reasonable enough time to consider them definitive

Yeah, fair. Codex has been out for less than 2 weeks at this point. I was relying on gpt-5 in August and opus before that.

I understand why you made it microservices, people make that too even when not using LLMs, because it looks like it is more organized.

But in my experience a microservide architecture is orders of magnitud more complex to build and understand that a monolith.

If you, with the help of an LLM, strugle to keep a monolith organized, I am positive you will find even harder to build microservices.

Good luck in your journey, I hope you learn a ton!