Review finding with a real in-repo instance: the structured runtime's
per-spawn final-assembly wrapper (prepend, post-next) re-injects
structured_output OUTSIDE the mode filter, so a structured child in
plan mode would see a tool the gate then denies — the soft policy and
the hard gate telling different stories. The suggested fix (make the
mode filter outermost) cannot beat that instance: prepend unshifts, so
the per-spawn listener always registers later and wraps outer.
Two-part resolution instead. Semantically, structured_output enters the
shipped plan allowlist — it is a child's pure result channel, the same
ask/report class as ask_user_question and exit_plan_mode, so the
filter, the re-injection, and the gate now agree wherever a structured
child runs in plan mode. Mechanically, the filter registers with
prepend anyway: it now wraps outside every append-registered listener
regardless of load order (regression test pins a pre-registered
post-next mutator being filtered), narrowing the documented cosmetic
residual to prepend-after-load listeners only, where the gate still
covers execution. Severity note: no execution breach existed — the gate
held throughout; this closes the prompt-honesty gap.