Derived or Observed: First-Principles Coverage Does Not Beat No Method, and a Non-Derivable Hazard Reaches a Duty Only Once Its Class Is Named

A procedure can be written in more than one form. We compare two forms of a duty (a gated procedure that governs a class of work) for repairing a confirmed software defect. The annotated form is written by reading a hazard registry and citing each entry it guards against, so the finished procedure depends on that registry to be understood. The cartographer form is written from first-principles analysis of the task, cites nothing, and is self-sufficient: an executor needs no external reference to follow it. We ask which hazards each form's procedure actually prevents. A local open-weight model (Qwen3.8-27B) writes the procedure in a single completion over a bare inference endpoint, and a blind judge scores, for each of ten pre-registered hazards, whether the procedure contains a step that would prevent it. The hazards are split in advance into seven that are derivable from the task and three that are not: a routing obligation upstream of the task, a session-close recording obligation, and a durability distinction learnable only from accumulated observation. Given the registry and told to write one gate per entry, the annotated form covers every hazard (210 of 210 derivable, 90 of 90 non-derivable); this is a manipulation check that the model follows the method, not a discovered effect. The two informative contrasts both involve the first-principles cartographer form: one against the no-method baseline, one against the annotated ceiling. The cartographer form covers the derivable hazards at a per-duty rate indistinguishable from a model given no method at all (0.64 versus 0.60; permutation p=0.44): writing from first principles buys self-sufficiency, not coverage. And it covers the non-derivable hazards almost never: 1 of 30 duties reaches any of them, against 30 of 30 for the annotated form (Fisher p=5×10⁻¹⁶). The pre-registered condition-by-class interaction, tested with the duty as the unit, is decisive (permutation p<10⁻⁴). The cartographer form's distinctive property is self-sufficiency: it cites no registry entry in any run, where the annotated form cites all ten in every run. We then run a fix the form's proposers specified but never executed: a meta-taboo scan that names two hazard classes, routing and session-close. It recovers exactly those two (routing 0 to 27 of 30; session-close 1 to 25 of 30) and not the third, the pure observation-only durability hazard it does not name (0 to 0 of 30). A blind rater judged coverage and an independent rater agreed (Cohen's κ=0.85); the direction is also corroborated without any judge, as the cartographer form never mentions routing across 30 runs and the scan form always does. Naming a class of hazard lets first-principles derivation reach it; a hazard whose badness is only apparent from accumulated observation, and that belongs to no named class, stays out of reach. The finding is a direction-and-rate result on one defect specimen and one model; the materials, runs, and scoring are public and reproduce on a 24 GB GPU with no paid API.