No fallbacks

“I would like to avoid fallbacks whenever possible” (user, 2026-10-07). No design has a primary path plus a degraded or alternative path (“if X fails, use Y”), and nothing ever falls back silently: a missing capability is a loud, typed failure that names its remedy, not a quieter substitute. Make the one path work and prove it.

• Forbidden, for example: awareness silently using a regex scanner when the syntax-tree package is missing; a red gate re-judged by a different judge; a reader that quietly accepts a second format with no end.
• Not a fallback: a test-only independent oracle declared as such; a typed refusal; a bounded retry of the SAME operation that then fails loudly.

Applies to all existing code (UR-19); each existing fallback becomes an owned fix task.