The subagent/provider-added and subagent/provider-removed events carry a
decision of their own — reactive consumer registration instead of a
load-order requirement the cordis Loader never guaranteed — buried in a
section of the prompt-variables RFC. Extract it: the mechanism, the
Loader-concurrency evidence, the rejected alternatives (apply-time
lookup, polling, assemble-time wording, name-keyed wording), and what we
give up (the absent-tool window, the dup-toolName blast radius) move to
2026-07-05-subagent-provider-lifecycle-events.md; the prompt-variables
RFC keeps the context contract and points there; index regenerated.