the access shortfall is the failure of *sufficient* against the idle baseline (P5)

Agent-decided, reversible (the thin-legitimacy round). The thin counterpart of Robust Openness is defined as the boundary half of sufficient: the reference, with the baseline what would have reached her with the agent idle, is no garbling of her later record. Both blocking rows of the eight-world model fail it while her credence is correct (src/thin_legitimacy.py, the open and covert blocking cases; Lean Witness.openness_necessary). Its placement — in legitimacy or in the authority layer — is reserved (the queue above); M3 keeps the thin counterpart of Robust Openness an open question, and this entry fixes its form, not its place. Rejected alternative: a thin counterpart stated on the reasons' routes rather than on the record's information, which no theorem here reaches.