Jev handles routing while Opus 5.5 reasons in a cheaper agent architecture
An agent loop sends routing, acceptance and goal-met judgments to Jev and only calls Opus 5.5 when real reasoning is needed, which the author says saves up to 200x in cost.
Jev + Opus 5.5. The setup everyone's talking about. This is how Frontier engineers are running flagship-level agents without paying insane prices. Opus 5.5 is already unreasonably cheap. With Jev, some tasks become almost free. It has only one problem. Running Opus 5.5 on every decision in an agent loop is expensive. Most of those decisions don't need flagship reasoning. Which agent runs next? Is this output good enough? Is the goal met? That's where Jev comes in. Jev is a decision model that runs at $0.042 per million input tokens, no output charge. It reads your system state and returns a typed answer, Choice, Score, or Noul. 200x cheaper than calling Opus 5.5 for the same question. The architecture: Jev decides. Opus 5.5 reasons. Agent executes. Opus 5.5 only fires when the task actually needs it. Everything else routes through Jev. Add prompt caching on top and Opus 5.5's static context drops from $4 to $0.20 per million tokens once warm. You get 1M context, adaptive reasoning depth, and near-zero cost on repeated context, with Jev keeping every routing decision off your Opus bill entirely. The guide in the image maps the full setup. Read the full breakdown on agents, loops, and graphs below.
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