Record the owner's decisions for t1, t4 and t6

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/DESIGN.md

@@ -211,6 +211,17 @@ above, including:
   by default). The owner doesn't like it.
 - **Fog of war reveals by line of sight.** Unexplored ground is black with a soft edge; the sky
   and the surface start seen. The owner chose line of sight over a plain circle around the bot.
+- **Bars pile neatly, and a Bar rack stores them (t1).** Bars that come to rest snap to a tidy
+  brick pattern so piles have no air gaps; a Bar rack machine (the Silo for bars) takes them from
+  a belt or tube, counts them and lets them out with F. The owner wanted bar storage that doesn't
+  waste space, like stacked ingots in real life.
+- **Hopper blocks replace hopper machines (t4).** 1-block Grinder and Saw blocks each work what
+  lands on them and drop it below, so a wider row is a wider, faster hopper. The Refiner and Stone
+  cutter leave the build menu; built ones in old saves keep working. The owner wanted hoppers of
+  any width.
+- **The bag is the vacuum's control panel (t6).** Each bag row has separate pick-up and blow
+  marks; a chip on the tool card sets pick-up to everything, only marked, or the same as the
+  first click; R over a grain toggles its pick-up mark. The owner found the shared ticks confusing.
 
 ## Ideas not built yet
 

docs/agent-log.md

@@ -4,6 +4,13 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-24: decisions for t1, t4, t6 (Claude Code)
+
+- Options given in chat; the owner chose: t1 neat bar piles plus a Bar rack; t4 Grinder and Saw
+  blocks replace the Refiner and Stone cutter (old ones keep working); t6 the bag as the vacuum's
+  control panel with separate pick-up and blow marks. Recorded in `docs/DESIGN.md` and as
+  subtasks on each task. Nothing built yet.
+
 ## 2026-10-24: t8 Fog of war for unexplored areas (Claude Code, Codex)
 
 - Decided with the owner: revealed by line of sight; unseen is black with a soft edge.