the principal policy class is reading versus susceptible, and the day-`n` credence process is the Laplace rule

agent-decided, reversible. The ecosystem's principals are a reading principal whose verdict is a function of the reason trace and a susceptible one whose disposition register the advisor can write and who takes side-channel messages as reasons; eager (commits into the barrier), launder and deliberate_dispose are variants for the coverage and settlement fixtures. The barrier-respecting principal waits while a protected concern is live and forgoes the slot rather than commit. The day-n price of the activation sentence across occurrences is the Laplace rule on settled outcomes, a concrete finite process standing in for an inductor's prices; its tracking bound |η_n − F_n/n| ≤ 3/(n+2) is kernel-checked and the logical-induction route is kept as the conditional corollary availability_of_provind. Rejected alternatives: a single parametrized principal (hides that mediation is a class-level fact); a principal that commits and lets the barrier void (kept as eager, not as the default); an empirical-frequency price without the prior (undefined at n = 0); building a logical inductor for the model (out of scope, and the tower stays paper).