Deploying dee76b1 proved a raw durable append insufficient: the 07:54 dispatch recorded the wandering selection, yet the request assembled half a second later still carried the deepseek header, because prompt assembly reads the Session Controller's in-memory selection and the internal Agent controller caches one per Agent. Call its own selectForNextRequest primitive — append plus cache refresh, still without saving the deployment default — and fall back to the public selectModel if the surface moves. Fixture gains the Controller; two cases pin fast-path and fallback.
wandering1
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