Sloped belts hold their load with moving cleats (t42); sloped filters are downhill shaking screens (t43)

The magic grip is gone: cleats every 8 face cells, 6 grains tall, carry
pockets uphill (about 71 grains/s against 90 flat) and overflow rolls
back. Sloped filters always run downhill; grains travel by gravity and
a shake, and sorting stays exact. Drawing needs another pass.

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

docs/agent-log.md

@@ -4,6 +4,52 @@ 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.
 
+## 2026-10-26: t42: sidewall belts with moving cleats (Codex)
+
+- Continued the uncommitted prototype. `sim/slope-conveyors.js` supplies moving barrier
+  lines (8 face cells apart, 6 grains tall), finite periodic pocket capacity and saved phase.
+  Removed slope grip; natural powder movement runs between steps and surplus rolls back.
+  Fixed the shared slope-to-screw mouth boundary so grains cannot fall under its casing.
+  Pixel/smooth drawing uses the actual mask, continuous dark far walls, matching previews/icons.
+- Files: manifest; sim cells/conveyors/slope-conveyors/machine-tick/items/pieces/blocks/world/save;
+  render slope-belts/slope-belt-shader/world; UI actions/selection/selection-pickers/previews/
+  build-menu/notebook; slope test suites and play.py; slope-flow/slope-cost experiments,
+  slope-conveyors scene, PROJECT_MAP, DESIGN and t42/t43. Removed both requested scratch files.
+- Reproducible `node tools/experiments/slope-flow.js`: sand, gravel, copper ore 71.3 and
+  coal 71.2 grains/s uphill, each 90.0 flat; 20-second window after 220 warm-up ticks.
+  Measured settled pile angles 33.7 degrees for all four. Final HEAD -> current stress measurement: 0.486 -> 1.038 ms/tick for 576 loaded
+  slope blocks (1024x512); no-slope powder microbenchmark, 2.14M calls: 45.07 -> 65.55 ms.
+  Median of five samples after warm-up; scripts use DG_HARNESS for the HEAD snapshot in
+  /tmp/t42-baseline. Barriers skip mask reads when none exist, but still have a CPU cost.
+- Opened shots/t42-belt-{pixel,smooth}-z{4,8}.png. Headless checks pass, including pocket
+  overflow, collision masks, unstamped bare-face sliding, joins, screw mouths, water, bars,
+  save phase, all eight drawing phases and unchanged seed hashes 777/77/4242.
+  Full python3 test/run_all.py --browser: ALL PASSED (26 headless suites, 360 play
+  checks, 15 smooth checks). Rebuilt dist and regenerated PROJECT_MAP. Both tasks moved to
+  Review. The owner still decides whether the lower rate feels
+  right. Pocket movement is a discrete envelope, not a calculation of individual forces.
+  No commit.
+
+## 2026-10-26: t43: inclined vibrating screens (Codex)
+
+- Diagonal filters always run downhill through all placement/settings/undo/paste paths;
+  R leaves a picked slope unchanged. The picker shows fixed downhill travel rather than two
+  misleading direction buttons. Flat filters retain their original carry. Slope grains get
+  gravity plus one mesh-contact nudge every 4 ticks (15 steps/s); unselected bars use the
+  same cadence. No whole-column carry or between-step grip on slopes.
+- Pixel and smooth mesh frames shake a little while loaded, with stable idle drawing.
+  Updated ghosts, icons, build text, notebook and the relevant sim/UI/render files listed
+  in t42 above. Added real browser drag/R/picker checks and art shake checks.
+- Both shapes and both sorting modes deliver the complete 64 sand + 64 gravel mix exactly.
+  Generous-feed discharge is 60.0 grains/s down-left and 59.3 down-right; rest passes through.
+  Opened shots/t43-screen-{pixel,smooth}-z{4,8}.png. Headless and smooth suites pass; the
+  first browser run found a hover fixture above the mesh and a later timeout. Corrected the
+  coordinate and reset picked slope state between fixtures. All new browser checks pass.
+  A subsequent run caught an existing 200 ms silo HUD timing race; wait for the expected
+  HUD text before the same assertion. Final full browser run: ALL PASSED, 360 play
+  checks plus 15 smooth checks; all 26 headless suites pass. t43 moved to Review.
+  No uphill-save migration. No commit; owner playtest remains.
+
 ## 2026-10-26: t44: rename screw tubes to screw conveyors (Codex)
 
 - Player text uses Screw conveyor; code uses screw/SCREW, including the piece id, part