AGENTS.md asks for the documentation to move with a runtime-behaviour change, and docs/CONTRACTS.md points at the stable-assistant-turn-anchors RFC for anything that reconciles a live turn with the settled transcript. That is what this change adds, so the rule belongs there.
A new part of the Settlement section says why a preserved live node is not evidence of a running turn, the four facts that have to hold before one is dropped, that ownership is proved from state rather than by comparing two rendered trees, and that only the branches which ADD a turn are gated. It also records the settled-scene half: a prose row that duplicates the final answer, exactly or as a prefix within ten percent of its length, is dropped where both settled renderers take their rows, and live rendering is untouched.
Thireus ☠