TRACE · ROUND 4

A benchmark in which language models design roller coasters that RollerCoaster Tycoon 2 builds, tests, and rates.

claude-opus-5 · 20260727-opus5-design-full · round 4 back to model →
events
50
tool calls
33
rejected
1
session
0:00
Session trace

  1. I'll start by loading the coaster tools.

  2. ToolSearch
    {"max_results":10,"query":"select:mcp__coaster__new_ride,mcp__coaster__place_pieces,mcp__coaster__piece_geometry,mcp__coaster__get_state,mcp__coaster__finish_and_test,mcp__coaster__valid_next_pieces"}
  3. Read
    {"file_path":"/home/sandbox/.claude/projects/-workspace/memory/rct2-coaster-scoring-levers.md"}
    1	---
2	name: rct2-coaster-scoring-levers
3	description: "Measured scoring levers for the RCT2 coaster-building contest (MCP \"coaster\" tools) — the intensity-10 cliff and the mid-course brake trick"
4	metadata: 
5	  node_type: memory
6	  type: project
7	  originSessionId: 2e22e2bc-f0c5-4828-b26f-60e933cdc7da
8	  modified: 2026-07-27T16:40:51.588Z
9	---
10	
11	In the RCT2 coaster contest (rounds started 2026-07-27), the reported `score` equals the ride's
12	`excitement` after a stock-similarity penalty. Measurements from round 2 (steel twister, ride_type 51):
13	
14	- **Hard cliff at intensity 10.0.** Same 99-piece layout: I=8.42 → E=6.85; I=10.58 → E=5.14;
15	  an early sloppy build at I=14.30 → E=1.97. Excitement is multiplied down in steps once
16	  intensity crosses 10, so *target intensity 8–9.5 and never above 10*.
17	- **Mid-course brakes are nearly free excitement.** Inserting two `{"t":"brakes","speed":18}`
18	  before the first corkscrew dropped intensity 10.22 → 7.63 with excitement *unchanged* at 6.74.
19	  Max lateral G fell 3.03 → 2.38, max positive G 4.83 → 4.09. High-speed corkscrews were the
20	  lateral-G source, not the banked turns.
21	- **Spend the headroom on… (2975 chars)
  4. Read
    {"file_path":"/home/sandbox/.claude/projects/-workspace/memory/rct2-coaster-circuit-closure.md"}
    1	---
2	name: rct2-coaster-circuit-closure
3	description: Geometry arithmetic for closing an RCT2 coaster circuit on paper before placing pieces
4	metadata: 
5	  node_type: memory
6	  type: project
7	  originSessionId: 2e22e2bc-f0c5-4828-b26f-60e933cdc7da
8	  modified: 2026-07-27T16:32:06.965Z
9	---
10	
11	Closing the loop in the RCT2 coaster contest is pure bookkeeping; doing it on paper first meant
12	a 92-piece circuit closed on the very first `place_pieces` run with zero rejections.
13	
14	Directions: 0=-x, 1=+y, 2=+x, 3=-y. Left turn cycles 2→1→0→3→2; right turn is the reverse.
15	`piece_geometry` only reports deltas for one facing — rotate them yourself as
16	(forward, left) offsets rather than re-querying per turn.
17	
18	Key facts:
19	- **Height parity.** Any flat-to-flat sequence of 25°/60° pieces moves z by a multiple of 16, so
20	  every flat run sits at `station_z + 16k`. `half_loop_up` + `half_loop_down` is the exception: it
21	  enters flat and exits at down-25, netting **−8** after the levelling `down_25_to_flat`. That breaks
22	  parity and makes the station unreachable — pair it with a second half-loop combo, or skip half
23	  loops entirely (vertical loops and cor… (2140 chars)

  5. Memory loaded. Round 3 banked 6.99 with a known-good 133-piece list. First move: **replay it exactly** to bank the score immediately, then experiment with the one lever I haven't pulled (average speed).

  6. new_ride
    {"dir":2,"ride_type":51,"x":34,"y":40}
    {"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"ride_id":0}
  7. place_pieces
    {"pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60","down_60","down_60","down_60","down_60","down_60_to_down_25","down_25","down_25_to_flat",{"speed":25,"t":… (2567 chars)
    {"circuit_closed":true,"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"placed_this_call":133,"total_placed":133}

  8. Closed on the first call — 133 pieces, cursor exactly back at start.

  9. finish_and_test
    {"bounds":{"max_tile_x":99,"max_tile_y":40,"max_z":680,"min_tile_x":26,"min_tile_y":30,"min_z":112},"placed_pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60"… (3487 chars)

  10. Banked **6.99** in the first two minutes — safe floor secured. Now I'll spend the rest experimenting. I have ~1.5 intensity headroom (8.45 vs the 10.0 cliff). Memory says inversions are worth ~+0.1 E each *if spread out*. There's a 5-tile flat straight after the `brakes 13` — a corkscrew pair spans exactly 3 tiles at dz 0, so it drops in cleanly, and at speed 13 the G-cost should be tiny.

  11. new_ride
    {"dir":2,"ride_type":51,"x":34,"y":40}
    {"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"ride_id":0}
  12. place_piecesrejected
    {"pieces":["begin_station","middle_station","middive_station","end_station"]}
    piece[2]: unknown piece name: middive_station

  13. Typo — two station pieces landed, continuing from there.

  14. place_pieces
    {"pieces":["middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60","down_60","down_60","down_60","down_60","down_60_to_down_25","down_25","down_25_to_f… (2610 chars)
    {"circuit_closed":false,"cursor":{"bank":0,"dir":2,"slope":0,"x":36,"y":43,"z":144},"placed_this_call":132,"total_placed":134}

  15. Two problems: I miscounted the lift (37 `up_25`, not 33 — that's the +32 z) and my corkscrew-for-flats swap isn't footprint-neutral. Let me get the real geometry instead of guessing.

  16. piece_geometry
    {"dir":2}
    {"deltas":[{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":0,"piece":"flat","slope_out":0},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":0,"piece":"end_station","slope_out":0},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":0,"piece":"begin_station","slope_out":0},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":0,"piece":"middle_station","slope_out":0},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":16,"piece":"up_25","slope_out":2},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":64,"piece":"up_60","slope_out":4},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":8,"piece":"flat_to_up_25","slope_out":2},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":32,"piece":"up_25_to_up_60","slope_out":4},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":32,"piece":"up_60_to_up_25","slope_out":2},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":8,"piece":"up_25_to_flat","slope_out":0},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":-16,"piece":"down_25","slope_out":6},{"bank_out":0,"dir_out":2,"dx_tiles":1,"dy_tiles":0,"dz":-64,"piece":"down_60","slope_out":8},{"bank_out":0,"dir_out":2,"dx_tiles":1,"d… (7346 chars)

  17. Good — now I have real numbers: a corkscrew pair is `(+3, ∓3, 0)`, not `(+3, 0, 0)`, so it can't drop into a straight. Abandoning that idea. Better use of my intensity headroom (8.45 vs 10.0): the brake-clamp is what's holding speed down, and both `max_speed` and `average_speed` feed excitement. I'll loosen the mid-course brakes — a pure tuning change with zero geometry risk. Lift first, counted carefully this time:

  18. new_ride
    {"dir":2,"ride_type":51,"x":34,"y":40}
    {"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"ride_id":0}
  19. place_pieces
    {"pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"}]}
    {"circuit_closed":false,"cursor":{"bank":0,"dir":2,"slope":0,"x":72,"y":40,"z":640},"placed_this_call":38,"total_placed":38}

  20. Lift came out one piece short (z=640, need 656). Let me fix precisely.

  21. ToolSearch
    {"max_results":5,"query":"select:mcp__coaster__undo_piece,mcp__coaster__best_result,mcp__coaster__style_best_ride"}
  22. undo_piece
    {"cursor":{"bank":0,"dir":2,"slope":2,"x":71,"y":40,"z":632},"pieces_placed":37,"removed":"up_25_to_flat"}
  23. place_pieces
    {"pieces":[{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"}]}
    {"circuit_closed":false,"cursor":{"bank":0,"dir":2,"slope":0,"x":73,"y":40,"z":656},"placed_this_call":2,"total_placed":39}

  24. Lift correct at z=656. Now the 94-piece tail, with the two mid-course brake clamps loosened (18→21, 13→17) to convert intensity headroom into speed:

  25. place_pieces
    {"pieces":["flat_to_down_25","down_25_to_down_60","down_60","down_60","down_60","down_60","down_60","down_60","down_60_to_down_25","down_25","down_25_to_flat",{"speed":25,"t":"brakes"},"flat_to_up_25","up_25_to_flat","flat_to_up_25","right_vertical_loop","down_25_to_flat","flat_to_up_25","up_25","up_25","up_25","up_25","up_25_to_right_bank","banked_right_turn_5","banked_right_turn_5","right_bank_to_flat","flat_to_down_25","down_25_to_down_60","down_60_to_down_25","down_25","down_25_to_flat","flat_to_up_25","left_vertical_loop","down_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25_to_flat","flat","flat","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat",{"speed":21,"t":"brakes"},{"speed":21,"t":"brakes"},"left_corkscrew_up","right_corkscrew_down","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_to_up_25","up_25","up_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_… (1542 chars)
    {"circuit_closed":true,"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"placed_this_call":94,"total_placed":133}
  26. finish_and_test
    {"bounds":{"max_tile_x":99,"max_tile_y":40,"max_z":680,"min_tile_x":26,"min_tile_y":30,"min_z":112},"placed_pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60"… (3488 chars)

  27. **7.04** — beat it. Average speed 455k→470k, intensity only 8.45→8.62. The lever is real and I still have headroom. Pushing harder on all three clamps:

  28. new_ride
    {"dir":2,"ride_type":51,"x":34,"y":40}
    {"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"ride_id":0}
  29. place_pieces
    {"pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"}]}
    {"circuit_closed":false,"cursor":{"bank":0,"dir":2,"slope":0,"x":73,"y":40,"z":656},"placed_this_call":39,"total_placed":39}

  30. Lift verified at z=656. Tail with all three clamps raised (25→28, 21→24, 17→20):

  31. place_pieces
    {"pieces":["flat_to_down_25","down_25_to_down_60","down_60","down_60","down_60","down_60","down_60","down_60","down_60_to_down_25","down_25","down_25_to_flat",{"speed":28,"t":"brakes"},"flat_to_up_25","up_25_to_flat","flat_to_up_25","right_vertical_loop","down_25_to_flat","flat_to_up_25","up_25","up_25","up_25","up_25","up_25_to_right_bank","banked_right_turn_5","banked_right_turn_5","right_bank_to_flat","flat_to_down_25","down_25_to_down_60","down_60_to_down_25","down_25","down_25_to_flat","flat_to_up_25","left_vertical_loop","down_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25_to_flat","flat","flat","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat",{"speed":24,"t":"brakes"},{"speed":24,"t":"brakes"},"left_corkscrew_up","right_corkscrew_down","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_to_up_25","up_25","up_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_… (1542 chars)
    {"circuit_closed":true,"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"placed_this_call":94,"total_placed":133}
  32. finish_and_test
    {"bounds":{"max_tile_x":99,"max_tile_y":40,"max_z":680,"min_tile_x":26,"min_tile_y":30,"min_z":112},"placed_pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60"… (3492 chars)

  33. Overshot hard — intensity 15.97, excitement 1.62. That's the cliff. But it's diagnostic: the previous run raised the *tail* brakes for only +0.17 intensity, so the blowup came from the **first** brake (25→28), which sets vertical-loop entry speed. I'll revert that one and keep the cheap tail gains.

  34. new_ride
    {"dir":2,"ride_type":51,"x":34,"y":40}
    {"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"ride_id":0}
  35. place_pieces
    {"pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"}]}
    {"circuit_closed":false,"cursor":{"bank":0,"dir":2,"slope":0,"x":73,"y":40,"z":656},"placed_this_call":39,"total_placed":39}
  36. place_pieces
    {"pieces":["flat_to_down_25","down_25_to_down_60","down_60","down_60","down_60","down_60","down_60","down_60","down_60_to_down_25","down_25","down_25_to_flat",{"speed":25,"t":"brakes"},"flat_to_up_25","up_25_to_flat","flat_to_up_25","right_vertical_loop","down_25_to_flat","flat_to_up_25","up_25","up_25","up_25","up_25","up_25_to_right_bank","banked_right_turn_5","banked_right_turn_5","right_bank_to_flat","flat_to_down_25","down_25_to_down_60","down_60_to_down_25","down_25","down_25_to_flat","flat_to_up_25","left_vertical_loop","down_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25_to_flat","flat","flat","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat",{"speed":23,"t":"brakes"},{"speed":23,"t":"brakes"},"left_corkscrew_up","right_corkscrew_down","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_to_up_25","up_25","up_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_… (1542 chars)
    {"circuit_closed":true,"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"placed_this_call":94,"total_placed":133}
  37. finish_and_test
    {"bounds":{"max_tile_x":99,"max_tile_y":40,"max_z":680,"min_tile_x":26,"min_tile_y":30,"min_z":112},"placed_pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60"… (3489 chars)

  38. Intensity 10.76 — over the cliff again. So the tail brakes are only cheap up to ~21/17; beyond that lateral G (2.55→2.94) in the final banked turns blows past 10. My **7.04 at (25, 21, 17)** is the optimum I found. Let me lock in presentation on the banked winner first, since that's safe regardless of what happens next:

  39. best_result
    {"bounds":{"max_tile_x":99,"max_tile_y":40,"max_z":680,"min_tile_x":26,"min_tile_y":30,"min_z":112},"placed_pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60"… (3488 chars)
  40. style_best_ride
    {"name":"Cinderfall","rail_color":"bright_yellow","support_color":"black","track_color":"bright_red"}
    {"presentation":{"name":"Cinderfall","rail_color":"bright_yellow","support_color":"black","track_color":"bright_red"},"score":7.039999961853027,"score_changed":false,"styled":"best_result"}

  41. Winner styled. Now recording the round-4 findings to memory — these matter for rounds 5 and 6:

  42. Edit
    {"file_path":"/home/sandbox/.claude/projects/-workspace/memory/rct2-coaster-scoring-levers.md","new_string":"Round 4 (best **7.04**, I=8.62) found the lever that beats the ~7 saturation:\n\n- **Average speed is the live lever, not drop height.** `average_speed` feeds excitement directly.\n  Loosening the mid-course brakes (18→21 and 13→17) on the *identical* round-3 layout took\n  average_speed 455354→470322 and E 6.99→**7.04** for only +0.17 intensity (8.45→8.62).\n  The 34-piece chain lift is slow and eats most of `ride_time`, which is why average speed is low.\n- **The intensity cliff is violently non-linear — step brakes by 1, never 3.** From the 7.04 config\n  (first/tail/end brakes = 25/21/17): 25/23/19 → I=**10.76**, E=5.27. 28/24/20 → I=**15.97**, E=**1.62**.\n  A +2 brake step cost 2.1 intensity; +3 cost 7.4. Bracket the optimum in steps of 1.\n- **Two different brakes, two different failure modes.** The *first* brake (bottom of the big drop)\n  sets vertical-loop entry speed → drives `max_positive_g`; leave it at 25. The *tail* brakes drive\n  `max_lateral_g` in the final banked turns (2.55 at I=8.62 → 2.94 at I=10.76 with positive G\n  unchanged at 4.70). Lateral G is wh… (1731 chars)
    The file /home/sandbox/.claude/projects/-workspace/memory/rct2-coaster-scoring-levers.md has been updated successfully.

  43. Time for one more bracketing attempt at (22, 18) — between my 8.62 winner and the 10.76 failure. Zero risk since 7.04 is banked.

  44. new_ride
    {"dir":2,"ride_type":51,"x":34,"y":40}
    {"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"ride_id":0}
  45. place_pieces
    {"pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"}]}
    {"circuit_closed":false,"cursor":{"bank":0,"dir":2,"slope":0,"x":73,"y":40,"z":656},"placed_this_call":39,"total_placed":39}
  46. place_pieces
    {"pieces":["flat_to_down_25","down_25_to_down_60","down_60","down_60","down_60","down_60","down_60","down_60","down_60_to_down_25","down_25","down_25_to_flat",{"speed":25,"t":"brakes"},"flat_to_up_25","up_25_to_flat","flat_to_up_25","right_vertical_loop","down_25_to_flat","flat_to_up_25","up_25","up_25","up_25","up_25","up_25_to_right_bank","banked_right_turn_5","banked_right_turn_5","right_bank_to_flat","flat_to_down_25","down_25_to_down_60","down_60_to_down_25","down_25","down_25_to_flat","flat_to_up_25","left_vertical_loop","down_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","flat_to_up_25","up_25_to_flat","flat","flat","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat",{"speed":22,"t":"brakes"},{"speed":22,"t":"brakes"},"left_corkscrew_up","right_corkscrew_down","flat_to_down_25","down_25_to_flat","flat_to_up_25","up_25","up_25_to_flat","flat_to_down_25","down_25","down_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_to_up_25","up_25","up_25_to_flat","right_corkscrew_up","left_corkscrew_down","flat_… (1542 chars)
    {"circuit_closed":true,"cursor":{"bank":0,"dir":2,"slope":0,"x":34,"y":40,"z":112},"placed_this_call":94,"total_placed":133}
  47. finish_and_test
    {"bounds":{"max_tile_x":99,"max_tile_y":40,"max_z":680,"min_tile_x":26,"min_tile_y":30,"min_z":112},"placed_pieces":["begin_station","middle_station","middle_station","end_station",{"chain":true,"t":"flat_to_up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25"},{"chain":true,"t":"up_25_to_flat"},"flat_to_down_25","down_25_to_down_60","down_60","down_60"… (3489 chars)

  48. (22,18) returned *byte-identical* results to (23,19) — I=10.76, avg_speed 482714. Brake speeds quantize, so 21→22 is the next distinct step and it already overshoots the cliff. **7.04 is the optimum on this layout.** Recording that:

  49. Edit
    {"file_path":"/home/sandbox/.claude/projects/-workspace/memory/rct2-coaster-scoring-levers.md","new_string":"- **Brake `speed` quantizes — adjacent values are not distinct.** Tail brakes at (22,18) returned\n  results *byte-identical* to (23,19): I=10.76, E=5.27, average_speed=482714. So the usable settings\n  are coarser than 1 unit; 21/17 (I=8.62) and 22/18 (I=10.76) are ADJACENT rungs with nothing\n  between them. Don't burn builds probing intermediate brake values — there is no fine tuning here,\n  and on this layout 7.04 was provably the top rung under the cliff.\n- **Two different brakes, two different failure modes.**","old_string":"- **Two different brakes, two different failure modes.**","replace_all":false}
    The file /home/sandbox/.claude/projects/-workspace/memory/rct2-coaster-scoring-levers.md has been updated successfully.

  50. Round 4 complete. How it went: **Banked early, then experimented.** I replayed round 3's known-good 133-piece list as the very first action — closed on the first call and locked in 6.99 within two minutes, which made every later experiment free. **Found a new lever.** Memory said excitement saturates near 7 via drop height/airtime/length. It does — but `average_speed` doesn't. The 34-piece chain lift eats most of `ride_time`, so average speed was low. Loosening the mid-course brakes on the identical layout took average speed 455k→470k and **E 6.99 → 7.04** for only +0.17 intensity. **Then found its ceiling.** Pushing further failed twice, informatively: - 25/23/19 → I=10.76, E=5.27 - 28/24/20 → I=15.97, E=1.62 (a +3 brake step cost 7.4 intensity) The two brakes fail differently: the first one sets vertical-loop entry speed and drives *positive* G; the tail brakes drive *lateral* G in the closing banked turns (2.55 → 2.94 with positive G unchanged). And the final probe at 22/18 came back byte-identical to 23/19 — brake speeds quantize, so 21/17 and 22/18 are adjacent rungs with nothing between. 7.04 was the top rung under the cliff on this layout. Two corrections worth noting: I miscounted the lift twice (37 then 32 `up_25` instead of 33) — I now verify lift `z` = 656 before committing the tail rather than trusting my own counting. And my plan to slot a cheap extra inversion into a straight died on real geometry: a corkscrew pair is `(+3, ∓3, 0)`, not `(+3, 0, 0)`, so it shifts 3 tiles sideways and can't drop into a straight run. Memory updated with the average-speed lever, the non-linear cliff measurements, the two G failure modes, brake quantization, and the corkscrew geometry — all directly actionable for rounds 5–6. **Best: "Cinderfall" — excitement 7.04, intensity 8.62, 5 inversions, 60 ft drop, 133 pieces (up from 6.99 last round).**

← claude-opus-5 · 20260727-opus5-design-full · all runs