instrument answer forces instrumented tier

minimum_tier is derived, never chosen. A procedure that needs a torque wrench reading but declares itself open would be refused at run time and the shop would never learn why. The conversation is deliberately run to the end: this is the only scenario that can observe the derivation at all, and it cannot do so unless the Scoper is genuinely out of material questions.

The agent was never properly asked, so there is nothing to score either way.