diff --git a/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md b/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
index 704023b4..18a2d134 100644
--- a/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
+++ b/03-DESIGN/01-to-be/47-milestones/G-20-lead-answers.md
@@ -639,3 +639,7 @@ names the principle that settles it, and is cited as "design 47 G A-n".
   `trunk.<n>`, the indexer's `<branch>.<revision>`), value `{records, missing?}`, and holds two more keys in the same
   form in every holder of pins: `made`, written once by create-only when the state is first used, and
   `pins-stated`, the `at` of the applied event; pins count only once a `pins-stated` later than `made` is applied.
+- **A-170** (§600, §481, §415, A-163; principles 7 and 8) Every ask to a build seat rides `accept.<queue>.<asker>`;
+  its kind is in its body only, as §600 says. A build seat definition's `stream` names only the queue, and the
+  generated accept subjects follow; the kind in the subject goes. §543's main subject takes `build` and `run` as
+  written, the checker's asks riding it until it goes.