Positive-Instruction Redesign of Skill Guidance — Design Spec

Status: Proposed (follow-up to the 2026-06-09 SDD review-dispatch work; separate PR per the one-problem-per-PR rule) Driver: Measured evidence (2026-06-10) that some negative instructions in skill prose backfire, while others work — and that the difference is predictable. Micro-tests on 2026-06-10 (opus, 5 reps per phrasing, programmatic scoring; harness described below) measured how guidance phrasing changes what a controller composes: |---|---|---| The doctrine (use this to