principle-foundational-thinking

1# Foundational Thinking
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3**Structural decisions** protect option value. **Code-level decisions** protect simplicity.
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5**Data structures first.** Get the data shape right before writing logic. Define core types early, trace every access pattern, and choose structures that match the dominant paths.
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7At code level, DRY the structure, not every line. Types and data models should converge. Three similar statements still beat a premature abstraction. Prefer explicit over clever. Test behavior and edge cases, not line counts.
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9**Concurrency corollary.** Before sharing state between actors, ask "what happens if another actor modifies this concurrently?" If not "nothing", isolate.
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11**Scaffold first.** If something helps every later phase, do it first. Ask "does every subsequent phase benefit from this existing?" CI, linting, test infrastructure, and shared types are scaffold. Sequence for option value: setup before features, tests before fixes. Keep commits small and single-purpose.
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13Each increment should land a coherent abstraction or deepen one that exists. Do not spread a new capability across callers as special-case coordination.
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15Subtraction comes before scaffolding. Remove dead code first, then lay foundations.