Engineering notes from GitGecko.

The original perimeter looked continuous, but it was painted by four CSS strips, four transformed corner fills, and two more header flanks. Every shared endpoint belonged to a different rasterization operation. That made a transparent sliver possible whenever layout, zoom, or device-pixel rounding moved one fragment differently from its neighbor.

The repair changes the ownership model. A pure geometry function now generates one even-odd SVG path: an overscanned outer rectangle minus a responsive inner opening. On wide screens, the opening bends around the header bridge. On compact screens, it begins below the full-width header. The topology never changes, only its measured coordinates do.

Golden-ratio powers choose bounded proportions, while exact cubic tangent construction handles the corners. Phi is useful for scale. It is not a substitute for the quarter-circle coefficient where the geometry already has a better answer.

A model is useful where judgment is required. It is wasteful where a parser, a schema, or a repeatable rule can establish the answer first. GitGecko runs deterministic analysis before agent review so known facts enter the reasoning lane as evidence rather than suggestions.

This split makes failure legible. A deterministic finding can name its rule and source location. A model finding can carry the context, prompt, provider, and trace that produced it. The interface does not pretend those two confidence classes are the same.

A finding without provenance asks the developer to trust a conclusion they cannot replay. A trace turns that conclusion into an inspectable chain: source material, deterministic evidence, retrieved context, model pathway, and final output.

Traceability is not an analytics garnish. It is the contract that lets a team challenge a review, compare providers, improve instructions, and prove which part of the system made a decision.