Shipped as HARNESS.7.ModelPin (commit 2babd3a). Found: on the one-call path the router only RECORDED its chosen model; the provider always sent its configured ChatModel, so UsesModel steered nothing. Now IAgentProvider.SendWithOptionsAsync carries schema and model; the spec declares ExtractModel=smart-local. Served through a logging proxy: model smart-local, schema 43 fields, golden values correct, no junk. Harness Catalog: 1 Deterministic, 6 Guarded, 24 Free.