What are you working on?

Very large codebase modernization/conversion to newer libraries for interop and compliance reasons. Fan out only works if you have enough to do without the agents stepping on each others work. It is amazing when you can do it. Conversions make it even easier because you have a baseline metric of tested functionality to meet. We did pull off mass fanout on an ambitious greenfield internal tool that went very well. It feels like my entire job now is figuring out how to parallelize as much work as possible for the agents.

Not too dissimilar from my approach at work these days, sans the "up to 32 agents" bit.

I try to work on planning docs, scrutinize them a fair bit to look for edge cases or anything that stands out as a problem, whatever.

Then break down the work further into meaningful chunks and hand those out to agents. Mostly one agent at a time but with the directive to use subagents as needed for implementation/review/whatever other perspective I want.

I feel like I'm exercising my brain similarly to how I had in the past. Before LLMs we'd whiteboard things similarly and figure out if a design made sense and like you said, chunk it into Jira tickets. it's really just the implementor (?) that's changed.

After a week, my throughput is limited by compute to run tests/checks. Worse if I'm compiling Rust.

What’s the point of opening a PR in such a setup? Why not simply merge to trunk, and spin review agents?

At the moment I'd say tradition. AI is new enough and scary enough that everyone still feels better with a human in the loop. That being said we rarely find issues when the architecture is planned in advance. Trust is growing.