{
  "completed_step": "C408",
  "next_proposed_step": "C409",
  "question": "Test the newly sourced Shem return loops under both existing17K source-corner exchanges, using the frozen cumulative register and reversed inherited phases. Track how the fixed−500 regular translation changes the original2K/17K rectangle, without shifting or fitting either exchange constant.",
  "reason_selected_after_current_result": "The new regular return correspondence is positive but cannot repair the older E² ladder. Its compatibility with the existing Mirror source corners is now the most direct unresolved529 question.",
  "executed": false,
  "authorization_remaining": 5,
  "fixed_scope": "Mirror/529; regular Gears Noah/Shem/Flood only; SP companion local. Fixed source inputs, no canonical/graph changes."
}