I had never really thought too much about WIP limits before reading this. I assumed they existed to encourage team members to help unblock each other, instead of picking up another ticket. However there is a cognitive reason, which is all the more pertinent with agentic coding.
We looked at the agents and thought: these things are cheap, they run in parallel, there’s no reason to limit how many I spin up. And that’s true — for the agents. The constraint was never the agents. The constraint is the single human in the middle whose job is to actually understand what came back.
This is old, old wisdom and we keep re-learning it. Jerry Weinberg, in Quality Software Management back in 1992, put a number on context switching: split your attention across two projects and you lose roughly 20% of your time to the switching itself. Add a third and you’re bleeding something like 40%. The lines on that chart are brutal, and — this is the important bit — they don’t care that your workers are robots. The switching tax is levied on you, the one doing the switching. Eight agents means you are basically not paying attention to any of them.
Kanban people have been shouting about WIP limits for twenty years for exactly this reason. Limiting work-in-progress isn’t about the capacity of the workers. It’s about the capacity of the system to finish things well. And a pile of half-attended-to agent output isn’t finished. It’s inventory. Expensive, unread, possibly-wrong inventory.