deterministic-core-llm-surface-pattern: Claude Skill that keeps 95 percent of an agent in deterministic code

A Claude Skill that states the 95/5 pattern: keep roughly 95 percent of an agentic system in deterministic, versioned code and confine model calls to the 5 percent that needs genuine language judgment. Its heuristic is whether running the same input twice must produce identical output. Logic that must be identical belongs in code, not a prompt. The repository has 7 commits and documents anti-patterns and testing implications alongside the rule.