Write an adversarially validated change proposal under proposals/, staging spec edits and/or core-product or test-infrastructure code changes, from an inline problem statement, or adversarially review and fix an existing proposal until it converges. Use when the user reports a spec or implementation defect, contradiction, or gap, asks for a fix or extension proposal, or asks to validate an existing proposal before sign-off. The proposal stages its changes for sign-off; it never modifies spec/, pkg/, or docs/ itself.
