Answerable Generativity in Innovation Governance: The Constitutional Grammar of Lawful Standard-Reopening

NOTE: This is paper No 2 of a series. Paper No 1 is Recognising New Capability in Innovation Governance (LXR-GOV-EVALGEN-2026-01, https://doi.org/10.5281/zenodo.21095860) — diagnostic to this paper’s constructive. A state that would recognise genuinely new capability must sometimes reopen the very standards by which it recognises. Its companion paper established that the coexistence of evaluative-layer generativity and reconstructable answerability is possible, conditional on the form answerability takes, and perishable even where the form is right, and it specified without building a device to hold the combination. This paper builds the device and defends it. It argues that the lawful reopening of a recognition standard is a distinct constitutional act with a grammar: a finite, rule-governed structure — declared mandate, bounded field, named responsibility, contestation of the standard, and revision duty — that makes a reopening well-formed rather than ill-formed. The grammar is shown to be an arrangement of materials English public law largely already possesses, grounded in vires and the principle of legality, the duty to give reasons, the anti-ouster principle, and sunset and review design; and it is tested against four live instruments — the Financial Conduct Authority regulatory sandbox and its legislated European counterpart, the Advanced Research and Invention Agency, and the Vaccine Taskforce — none of which holds all five features. The paper then anatomises capture, the reproduction of the grammar’s form without its licensing structure, in six modes each answered by a structural safeguard. Finally it supplies the rule the features cannot: a downside-allocation rule that fixes, in advance, which instrument bears a failed bet — a normative construction transposed from the accounting-officer and ministerial-direction practice in which the form already exists. The rule dissolves the defensive-rationality equilibrium the companion paper diagnosed, and converts the grammar from a licence into an institution. The paper closes on the kind of legal order that can hold answerable generativity: one whose forum cannot be closed.