Re-auditing the review-fix commits surfaced a regression the REPLACE
re-assert (825cbab3) introduced: unconditionally rebuilding both arrays as
filter(...)+append moved structured_output to the END of the model-visible
tool list on every untampered assembly (overriding the registry's
toolOrder/lexicographic contract) and moved the instruction section to the
absolute array end — renderPrompt reads ARRAY order, so any section above
order 190 would render before the trailing instruction, violating the
sections-sorted-ascending contract. The presence-check version it replaced
touched neither array when the entries were intact.
The re-assert keeps its REPLACE content semantics but is now
placement-preserving: the tool is replaced IN PLACE (duplicates collapse,
append only when stripped); the section is re-inserted at its
ascending-order position (the first entry above 190 — exactly where the
registry's stable sort put it, so the untampered path reaches the model
byte-identical). Pinned by two regression tests that fail against the
filter+append form: untampered placement (tool before a lexicographically
later tool, instruction before an order-200 section) and tamper recovery
(stripped section re-enters its band; an added duplicate collapses to one
right-schema entry).
Tianyi Cui
96c3c94f85