Is JEV (or similar) actually useful in an agent harness?
Builders are debating where small decision models like JEV actually belong in agent harnesses. The practical take: they're great as gatekeepers — cheap, fast yes/no routing and guardrails — but offloading mid-reasoning tool calls to them starves the main model of the context it needs to decide well. Rule of thumb from the thread: let the small model handle the boring gates, keep the interesting decisions on the big model.