Claude Opus 5.5

Written by Claude (drafted by Sonnet 5.5, checked by Opus 5.5) from the run's own logs (events.jsonl, episode.json, results.json, interview.md); it is a reading of the run, not part of its score. The checker is the same model as the player.

• Model: Claude Opus 5.5 (claude-opus-5-5) on Anthropic's API, reasoning medium, output limit 32,768 tokens
• Benchmark: The Sinkhole construction (no arms), version 1.7.3 (commit e0e0eb4), from the save the human reference game on this map started from; 45 min of game time at speed 40, the length of the person's game (44 min 58 s); no playbook; waits played fast. Weapons and armour in store count nothing toward net worth; sold at a marketplace, they bring their gold.
• Run fc3d2140, series 20261019T082447-7e09b8c5, 2026-10-19, host on the game machine: Opus's no-arms game on this map, a fresh series with no memory of its others. Its weapons-counted pair is its 1.7.1 game (run 9c8871df, series 20261015T185216-6a2a0659, commit 674e7ba, host on a Mac); its Sinkhole games from earlier rounds are runs 256f1790 and 0a79c93b (1.6.2). This game counts on the website's leaderboard.

Result

A full-budget score: the run used all 2,700 game seconds. Net worth grew by 14,694 over leaving the game alone, 37.3% of the person's 39,436, against 33.5% in the 1.7.1 game. By the website's formula (80% net worth, 10% each population and popularity; shares from doing nothing to the person; net-worth share clipped to −1..2) the score is 39.3: 29.81 points from net worth, 2.83 from 146 people and 6.70 from popularity 67. It is the highest of Opus's four Sinkhole games. Gold is 53% of net worth and iron 32%: it mined 427 iron and sold 190 of it at 39:08 for 4,370 gold; the 237 kept are 5,451. The town ended with 24 idle peasants, 56 empty places in its hovels, no empty pile in the stockpile and taxes off.

How the game went

Times are the game clock when a call began, read from the recording; readings quoted from observations carry the run clock, which reads a few seconds later.

0 to 10 minutes: iron, then taxes and half rations. Three woodcutters (0:01), orchards and a dairy (0:45), four hovels (1:26), the marketplace (2:45), 100 planks (3:01); with 23 idle peasants it placed four iron mines at 3:53 (the call ran 78 s). Average taxes (6:49) and half rations (7:02), with the starting meat nearly gone (food 20 at 7:01), took popularity from 98 to 60 by 10:07; low taxes (8:39), a chapel for 250 gold (9:02), full rations (10:06) and no taxes (10:13) followed. First iron reached the stockpile at 6:36.

10 to 20 minutes: quarries, bows, iron in fives. A quarry and tether on the deposit 84 tiles away (11:13), a second quarry (12:24), and at 15:08 an armory and three fletcher's workshops. No stone came: it inspected a quarry (14:34) and its tether (14:54) and moved the camera (15:52); the first compaction was at 16:00, with stone still 20. Planks (16:03), five mines (16:49, 14 in all), the first stone (17:17), two more quarries (18:03), low taxes (19:17); population passed 100 at 20:24.

20 to 35 minutes: more jobs, then wheat. Dairies and orchards (20:54), hovels (21:55), the first bows sold (22:27), planks (23:08), two mines, four woodcutters and two workshops (23:58), five woodcutters (25:27), a second granary (27:18), no taxes (27:44). Five mines (28:01, 23 in all) and two wheat farms, then six more wheat farms and four hops farms with hovels, to 34:17; housing rose from 146 to 202. At 32:26 expand_storage found no free ground beside the stockpile, and at the 34:28 reading no pile was empty. The second compaction was at 34:27.

35 to 45 minutes: selling and waiting. The last build call was at 34:48 (two orchards). From 34:30 it made seven sales for room (wood, iron, stone), sold bows, set no taxes at 39:02 and otherwise waited 20 to 100 s at a time. Population stood at 146 from 35:31.

Each column is the last recording frame at or before that minute. Before End the net worth row counts gold, wood, stone, iron and food (at 4) and leaves out wheat and hops (under 100 at 35 minutes, about 450 at 40), so it reads low; End is the game's own figure. Mines are counted from the start of the call that placed them.

Weapons

It built them anyway, small, and sold what they made. Its opening reply planned for "a fletcher or poleturner" later to turn wood into weapons to sell, and to sell any in the last minutes because they count nothing in the armory. At 15:07, with 24 idle workers and wood to spare, its reasoning called fletchers "a great use"; at 15:08 it placed an armory (5 wood) and three fletcher's workshops (20 wood and 100 gold each). The 16:00 handoff priced a bow at 2 wood, worth 1 each, and a sale at 15, and said to sell bows often. Two more workshops followed at 23:58 (no reasoning was logged for that turn). It never called set_workshop, so all five made bows, 1.0 to 1.7 a minute together in the readout (0.2 to 0.3 each, 3 to 5 gold a minute), against 0.5 to 0.8 iron, 12 to 18 gold, for a mine. It called them "underperforming" (25:27), passed over fletchers as too slow at 32:54 and built no more.

They made 36 bows. It sold 35 for 525 in five calls of lots of five (22:27: 5, 30:17: 5, 40:54: 15, 42:55: 5, 44:44: 5), each reply matching the recording's gold; one bow was left, worth nothing. The wing cost 500 gold, 105 wood in buildings, 72 in bows (2 each, by prompt/game-mechanics.md) and five jobs, filled while idle peasants read 17 to 24 and open_jobs 0 in every reading, so no one was taken from other work. Gold ends +25; with the 177 wood at its sell value of 1 the wing returned 525 against 677, −152 of net worth (0.3 points); with the planks at the 4 gold it paid, about −683.

The 1.7.1 game built ten fletcher's workshops (armory 4:31, workshops from 5:01, the last four at 30:15) and two armories, set them to crossbows (eight set_workshop calls) and sold nothing. It ended with 43 crossbows (1,290) and 16 bows (240): 1,530, 9.9% of its 15,424. They cost 1,000 gold and 371 wood (workshops 200, armories 10, weapons 161), so under that rule the wing returned 1,530 against 1,371 (+159); under this game's rule the stock counts nothing and that game ends at 13,894 and 31.6 points. Across Opus's Sinkhole games the weapons shrank: 148 pieces worth 3,714 (27% of net worth) and 221 worth 2,560 (16%) in the 1.6.2 games, 59 worth 1,530 in 1.7.1, 36 bows here.

Iron went into no weapon in either game (bows and crossbows take wood only): it mined 427 here and 432 there. Wood went in at 177 against 371 and workers at 5 against 10; the 500 gold not spent on workshops stayed in the treasury (gold never fell below 921 after the opening). The logs show the rule changing the plan only in when and how much: the wing started at 15:08 here against 4:31 there, with five workshops against ten.

Beside its other games and the other models

The pair differs in more than weapons: the version (1.7.2 retries a blocked build_structure target only within its footprint's side plus a tile, where 1.7.1 searched 12, and keeps room beside stockpiles; 1.7.3 added this benchmark), the host (a Mac there, the game machine here) and the model's own choices. Here three placements moved 5, 2 and 11 tiles, inside their reach, and five were not placed; both stockpiles ran out of room (35:41 there, 32:26 here).

The score is 4.6 points higher: net worth +2.97, popularity +2.00, population −0.36. Scored by this game's rule the 1.7.1 game ends at 13,894, so this game stands 2,995 and 7.7 points ahead, not 1,465 and 4.6. Iron mined is level; the differences are in what else it made: 12 wheat and hops farms placed from 28:01 (+888 for 180 wood), 216 stone mined against 172 (first quarry at 11:13 against 20:12, first stone at 17:17 against 25:13), 740 less gold spent at the market (net worth lost 900 against 1,355), 500 less in workshops and taxes 134 lower. Popularity ended at 67 against 47: it set no taxes at 39:02, where the 1.7.1 game moved to average taxes at 41:27 and low at 43:02.

In the 1.7.1 round (weapons counted) Gemini 4 Argon scored 52.4 and GPT-6.1 Sol 50.4, ahead of Opus's 34.7, Claude Sonnet 5.5's 33.1 and Muse Wonder's 33.0; this game's 39.3 would stand third of eleven. Those games held 370 to 1,530 of weapons (Opus's the most), 0.8 to 3.1 points, so leaving them out moves no one past it. Among the no-arms Sinkhole games so far it leads: Claude Haiku 5.5 8,243 / 23.8, Claude Sonnet 5.5 15,246 / 35.3, this game 16,889 / 39.3. On the batch's other maps its no-arms game also beat its weapons-counted game (Oasis by the Sea 37.7 against 32.9, Large Barren Desert 67.1 against 19.1; those pairs share a version).

What held it back

• Jobs, not housing. Idle peasants read 17 to 24 with no open job from 5 minutes, and 24 in 15 of the 19 readings after 22:30; population stood at 146 from 35:31 with 56 empty places. Jobs did bring arrivals: the five mines of 28:01 took idle from 24 to 17 at 29:11 and back to 23 by 30:34, population 122 to 137. Nothing was built after 34:48, with 2,236 to 3,137 gold in hand; its logged reasoning at 36:43 and 37:44 was to watch and wait.
• A full stockpile. At 39:03 iron and stone had room 0 and the readout said their producers stop; iron read 16.7 a minute at 37:46 and 12.0 at 40:34. It sold wood for room, and at 39:08 iron. At 44:45 every pile held something; wheat and stone had room 0, iron room for 56 and planks for 29.
• No chain beyond raw goods. The eight wheat farms (28:01 to 32:56) fed no mill and the four hops farms no brewery; one food was eaten in 30 of 48 readings.
• Taxes against popularity. Three spells above no taxes (6:49 to 10:13, 19:17 to 27:44, 32:19 to 39:02) brought about 2,780 gold, 5.6 points at the formula's weight, and popularity read 60, 60 and 49 at their ends. The chapel's religion factor read 0 in every reading from 10:07.
• Planks bought and sold. 300 bought at 4 (1,200 gold, 900 of net worth lost) and 320 sold at 1; wood stood at 103 to 180 between 24 and 35 minutes with 17 woodcutters.
• The weapons wing: about −152 of net worth.

What worked

• Iron. Four mines at 3:53, 23 by 28:01, 100 iron at 21:16; the 427 mined were worth 9,821 at 23 each, 58% of the final net worth.
• Selling to keep the mines running. The 39:08 sale cleared 190 iron of room; iron went from 146 to 237 by the end (91 in 5:39, 16 a minute, 2,093 of net worth, with room 0 at 39:03).
• A late crop. Twelve farms in the last 17 minutes were 888 of net worth for 180 wood.
• Food. After the first 10 minutes it never fell under 44 and ended at 168.
• Placements held: all 117 build_structure placements reported as placed are in the final count of buildings; five tries did not go through and no call was refused.

Market

Bought: 300 planks, three lots of 100 (3:01, 16:03, 23:08), 1,200 gold; no food. Sold: 35 bows for 525, 320 planks for 320 (four calls), 190 iron for 4,370 and 140 stone for 980 (two calls), 6,195 gold in all, where the replies add to 4,125. Only the 39:08 iron call differs: it asked for 100 and reported 100 units and 2,300 gold, and the recording shows iron 336 to 146 and gold 3,202 to 7,572 (the game sells 50 a click with 200 or more in stock; the reply's stock and gold were right). Planks (162, 122, 83 and 143 in stock) and stone (192 and 184) were under 200 and match. Selling left net worth unchanged except the bows (+525). The 15 calls took 289 game seconds. None of its 107 tool calls was a game_action, so it set no automatic trade by clicks, and every fall of gold in the recording is accounted for (1,200 planks, 500 workshops, 250 chapel).

Cost and speed

61 turns, 107 tool calls (34 find_sites, 27 build_structure, 15 market_trade, 10 waits, 7 set_tax, 14 others), 3.41 million tokens and $1.818 at Anthropic's list prices ($4 per million input, $20 output, $0.20 cache read, $5 cache write): preparation $0.164, play $1.539, compaction $0.115. The interview cost about $0.042 more (51,063 tokens, 48,422 read from the cache). The agent run took 40.0 real minutes, 6.0 of them waiting for the model. The context was compacted twice (16:00 and 34:27, 32 seconds in all); each compaction was one request and succeeded on the first. All 61 requests read the prompt cache (96.8% of input tokens) and none failed.

Of the 2,700 game seconds the 27 build calls took 1,452, the 10 waits 535 (played fast, 231 real seconds), the 15 market calls 289 and the host's 5-second top-up after 34 replies that acted without a screenshot 170. The build calls placed 117 buildings: 12.4 game seconds each, 4.3 a call. The 1.7.1 game's 29 calls took 1,512 s for 129 (11.7 s each, 4.4 a call). That game's host was a Mac and this one's the game machine, and the version and the mix of buildings differ, so the 0.7 s says nothing by itself.

The interview

Opus put the gap to the person (about 40% of their net worth) down to population capped by 24 idle peasants with no open job, popularity spent on low taxes, no product that adds value (wheat late, no mill), a stockpile that choked production, and early gold spent on planks. Playing again it would build the wheat, flour and bread chain early, plan storage around the stockpile, stop at six to eight woodcutters, get religion working and add inns, add jobs whenever idle reaches 24, and sell surplus continuously. It praised the tile-based tools and the readout's per-pile room and per-building production, and asked for a note on popularity factors and a warning when idle peasants are capped with housing empty. It did not mention bows, the fletchers or the armory.

Against the game these match: 16,889 against 41,631, 14,700 above leaving the game alone; 146 against 506 people and 67 against 99; 24 idle with no open job; the chapel's factor at 0; wheat farms late with no mill; low taxes at about 84 gold a month (the 32:19 reply); the stockpile full and wood, iron and stone sold in the last ten minutes; 17 woodcutters. These do not: it spent 1,200 gold on planks, not 800 (the second handoff also said 200 planks and 800 gold, with three lots already bought); "56 houses" are 56 places in 24 hovels; "twenty minutes" of stall is 24, from 20:40. Not checkable: "seven [woodcutters] would have done", and that it built over the stockpile's room (the tool said only that no free ground touched it, at 32:26).

For the harness

• The market_trade reply undercounted the 39:08 iron sale (100 units and 2,300 gold against 190 and 4,370): the known 1.7.3 fault at 200 or more in stock. stock and gold were right, the model did not use the wrong figures, and scoring is unaffected.
• No room beside the stockpile (32:26), as in the 1.7.1 game (35:41), although 1.7.2 keeps room beside stockpiles; no placement here was moved for it. The remedy named selling or demolishing; it sold goods and did not ask again.
• Placements: a mine off the ore was rejected (7:08), two hovels were not placed with nearestFit 8 and 9 tiles off against a reach of 5 (7:38), a dairy farm (10:17) and a quarry (12:24) were not placed; each result named what to do.
• No harness warning for the idle cap, which the benchmark text states and the stats show; Opus asked for one.
• No provider errors, stalls or garbage-collection watchdog events (no forced collection in 478 memory samples). The game saved at the end ("claude opus 5-5 1-7-3 fc3d21").