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 the Anthropic API, reasoning medium, output limit 32,768 tokens
• Benchmark: Oasis by the Sea construction, version 1.7.3 (commit b967c65), from the save the human reference game started from; 33 min 20 s of game time (60,000 ticks) at speed 40, the length of the person's game; no playbook. Weapons and armour in the armory count toward net worth at the rules' prices, as since 1.6.0.
• Run 5aa57408, series 20261016T201053-354922a4, 2026-10-16: Opus's weapons-counted game of the 1.7.3 batch, a fresh series with no memory of any other game. Its no-arms game (run f95496e6, series 20261016T204131-27075351) was played right after.

Result

A full-budget score: the run used all 2,000 game seconds. Net worth grew by 6,070 over leaving the game alone, 33% of the person's 18,293. With 62 people and popularity 34 the score is 32.9 by the project website's formula (80% net worth, 10% each population and popularity, the net-worth share clipped to −1..2); this game counts on the website's leaderboard. It is 4.8 below its no-arms game, 4.0 above its 1.6.3 game and 19.1 below its 1.5.1 game.

The stored goods are 223 iron (5,129), 161 stone (1,127), 15 crossbows (450), 122 wood (122) and 3 apples (12). Iron is 70% of net worth, iron and stone together 86%. The town ended with 12 empty places in its hovels, no empty stockpile pile and 3 food, which the game counts as no month's.

How the game went

Times are the game clock when a call began (the recording's clock; the run clock in the observations reads a few seconds later). The game is paused while the model replies; a build or buy call keeps it running for 12 to 101 seconds while it clicks.

The opening, 0 to 5 minutes. Its first reasoning saw the granary already built and took trees to be scarce (a 42-tree grove 62 tiles from the keep, one of 8 trees at 27). The first build call, at 0:04, placed an iron mine, two woodcutters at the big grove and a marketplace the game refused ("Too close to signpost"); it ran 101 s. The marketplace went up at 1:54, and 100 planks bought at 2:12 stopped at 75 for want of storage room. Two hovels, two iron mines and a dairy farm followed at 3:34, two stockpile piles at 4:57 and average taxes at 5:28. The town stood at its 10 places until the first hovels at 3:55.

Mines and thin food, 5 to 16 minutes. Four orchards (5:44 to 11:02), 25 apples bought at 6:57, 25 cheese at 12:15, and ten iron mines by 12:15, the last it placed. Popularity fell from 99 at 5:45 to 57 at 11:44 under average taxes; a warning at 11:00 led to no taxes at 11:23. Five hovel placements at 12:42 and 13:43 were refused or found no room, and the population stood at its housing for 4 min 50 s of the 7 min 50 s from 12:44 to 20:34. Two mines were refused at 14:49 ("must be built on Iron ore"); at 15:23 it sold 20 iron for 460 and at 15:37 bought 100 planks.

Weapons and stone, 16 to 25 minutes. At 16:39 an armory and three fletcher's workshops went up (a mine was refused again) and were set to crossbows from 17:41. Two quarries and two tethers came at 18:17, two hovels and a fourth fletcher at 20:13. Food fell to 14 at 21:47; 25 bread bought at 21:49 left 57 gold. Taxes went to average at 22:51, the context was compacted at about 24:50, and the last building, an ox tether, was placed at 25:00.

Waiting, 25 to 33 minutes. Taxes went to none at 26:22 and 25 bread was bought at 26:29. Waits of 60 and 150 s followed (the host noted at 30:38 that it had only waited and read for 3 minutes), taxes went to low at 30:39, and a warning ended the next wait at 32:36 after 108 s: popularity had fallen from 50 to 33. Taxes went to none at 32:38; the deadline came during the last wait.

Each column is the last reading at or before that minute. Up to 30 minutes the net worth row counts gold, wood, stone, iron and food (at 4) as the recording logs them; weapons are left out, so it reads low (the 450 in crossbows is in the End value only).

Weapons

It built an armory and four fletcher's workshops, no other workshop and no armour. Its opening plan said it might add a blacksmith or armorer and an armory later; at 12:42 it weighed iron into swords against more mines, and at 16:39 (gold 438, wood 141, 22 idle peasants) it chose fletchers, expecting about a crossbow a minute from each. It priced the blacksmith at 100 gold; the table in prompt/game-mechanics.md says 200 gold and 20 wood. The armory and three fletchers went up in the call that began at 16:39 (gold 438 to 238) and were set to crossbows between 17:41 and 18:17; a fourth, placed one tile from its target in the call that began at 20:13, was set at 20:52. No crossbow was in the armory at 20:15 and two were at 20:53. From 21:51 the readouts gave 0.3 crossbows a workshop a minute (1.0 to 1.3 for the four; one window, at 23:40, gave 0.1 a workshop); at 22:51 its reasoning said to "skip crossbows since they're too slow to produce", and it built no more. The end value is 15 crossbows, 450 at the rules' 30 each: 6.2% of net worth and 2.0 of the 32.9 points (30.9 with weapons worth nothing).

The cost, from the same table: 400 gold and 80 wood for the workshops, 5 wood for the armory and 45 wood in the crossbows (3 each): 400 gold and 130 wood. The crossbows returned 450 for 530, about 80 less than keeping both as gold and wood at store value (0.4 points; about 470 less with wood at the 4 gold it paid for planks, though 122 wood was left over). A workshop made about 9 gold a minute; an iron mine made 23 (1.0 to 1.1 iron a minute in every readout from 19:11). The 400 gold could have stayed as gold, which counts 1:1; bought 50 bread (8 gold each) when the granary held 14 and gold was 257 (21:47); or paid for a chapel (250 gold), which its reasoning never returns to after the opening plan and its no-arms game placed at 16:38.

Beside its other games and the other models

Against its no-arms game this one ended 250 lower: 913 less gold, 392 less stone, 144 less wheat, 136 less wood and 12 less apples, against 897 more iron and 450 in crossbows. Its 17 fewer people and 29 fewer popularity points are 3.8 of the 4.8 score points between them. That game bought 640 gold of goods against 1,860 here, built a chapel and no workshop, and fell under 50 popularity for 1 min 46 s (about 5 minutes here). Weapons added 2.0 points here, so without them the gap would be 6.8.

Against the 1.6.3 game, with 14 weapon workshops (988 in weapons, 1,400 gold), this one spent 400 gold on workshops and ended 501 higher in net worth with 7 more people and 14 more popularity points; neither built bread. The 1.5.1 game had no weapons and scored 19.1 more (12.1 points of net worth, 2.3 of population, 4.8 of popularity) with a 13-bakery bread chain, 107 people and popularity 82; with this game's crossbows counted for nothing the gap would be 21.1, so weapons do not explain it.

Among the first six games of the 1.7.3 batch (Haiku, Sonnet and Opus, each in both versions) 32.9 is third, behind Opus no-arms 37.7 and Sonnet 36.5. The weapons game scored higher than its no-arms game for one model in three (Sonnet 36.5 against 31.4; Haiku 23.0 against 26.9; Opus 32.9 against 37.7), with weapons worth 240, 810 and 450. Among the 1.6.3 round's second games on this map it would stand fifth; the versions differ.

What held it back

• Taxes against popularity. Four raises (5:28, 14:34, 22:51, 30:39), each followed by 2 to 4 points lost a month: 99 to 57 by 11:44, 68 to 54 by 19:11, 65 to 44 by 26:23, 50 to 33 by 32:39. The tax paid 20 gold a month at 5:36, 56 at 23:02 and 44 at 30:47. Popularity was under 50 for about 5 minutes (25:31 to 28:03, and from 30:50); people left, 74 to 65 by 28:00 and 62 at the end. Against the 30:40 reading the last raise left the end with 190 more gold (+0.8 points), 16 less popularity (−1.6) and 12 fewer people (−0.6).
• Buying wood and food. 1,860 gold of goods bought lost 1,195 of net worth against the sell price, 5.2 points; the 265 planks (1,060 gold) lost 795 of it. It had six woodcutters, and 122 wood was left.
• Three mines never placed. Ten mines by 12:15; three later attempts (14:49, 16:39) used spots from a hovel's and a fletcher's search and were refused. It never asked find_sites for a mine after 11:42, and its handoff said none were left; its 1.5.1 game placed 12 and its 1.6.3 game 11. At about 1.0 iron a minute a mine placed by 16:00 would add about 350 by the end, if the strip had room.
• Thin food and a housing cap. Four orchards and a dairy; no wheat, mill or bakery (a wheat farm search at 11:33 found nothing within 25 tiles of (450, 380)). Food was 3 at 26:23, 30:40 and the end. Housing stood at 74 from 20:34 and the population at 74 from 23:50; wood was 71 to 124 from 28:00, and a hovel is 6 wood for 8 places (0.4 points).
• The last 8 minutes. After the tether at 25:00 it built nothing, with 428 gold at 26:23. The 23:39 search had listed a second quarry site, (377, 393), unused; a quarry is 20 wood and gave 2.1 stone (about 15 gold) a minute at 32:39.

What worked

• Iron and stone. Ten mines gave 223 iron in store (5,129; 20 more sold), 70% of net worth; five quarries and five tethers gave 161 stone (1,127), 10.7 a minute at 32:39.
• No screenshots. The run holds three images (the first screenshot, the overview, the host's after compaction); all nine waits asked for none, and every placement was by tile. Every placement reported as placed is in the final count. Of 56 placements in 18 calls, 11 did not go through; no call was refused, and the only tool error was the last wait.
• Warnings and the handoff. It acted within 25 s on three of four warnings (11:00, 21:47, 32:36) and left the first (7:23) for four minutes. The handoff at compaction held buildings, tiles, rates and next steps; its next calls followed (taxes to low at 24:53, the tether at 25:00).

Market

265 planks (4 each, worth 1), 25 apples, 25 cheese and 50 bread (8 each, worth 4) bought for 1,860 gold; 20 iron sold for 460. The purchases lost 1,195 net worth against the sell price (planks 795, bread 200, apples 100, cheese 100); selling leaves net worth unchanged. The 100 planks at 15:37, paid for by the iron, went to the armory, fletchers and quarries (65 and 50 wood in the next two calls), not to the two mines it had planned. These are units at the market's fixed prices.

Cost and speed

40 turns, 73 tool calls (18 find_sites, 18 build_structure, 9 set_tax, 9 waits, 8 market_trade, 11 others), 2.19 million tokens and $1.135 at the profile's prices ($4 per million input, $20 output, $0.20 cache read, $5 cache write): preparation $0.164, play $0.927, compaction $0.044. The interview cost about $0.036 more, with 40,771 of its 43,070 tokens read from the cache. The agent run took 27.9 real minutes, 4.1 of them waiting for the model; the context was compacted once (13 s). All 40 requests read the prompt cache, 97.3% of the input tokens. Of the 2,000 game seconds, the 18 build calls took about 827 (median 43 s), the market calls 271 and the waits 588; fast-forwarding the waits saved 133 s of real time.

The interview

Opus put its result at "about six times" the baseline and under half the person's, and named three causes: no processing chain, food and popularity (apples alone, taxes near 50, housing at 74, "20 people" idle) and no fear factor. Playing again it would build food first and a bread export, a chapel and zero taxes, gallows and gibbets, and housing early. It praised tile placement, find_sites, the production readout and the warnings, disliked action calls costing "about 30–60 seconds" and refused placements, and asked for a tool for the market's auto-trade thresholds and a popularity outlook. Its error was "strategic, not mechanical": it read net worth as stockpiling raw goods.

Against the game, the figures match (7,290 and 19,513, 62 and 202, popularity 34 and 100, worker efficiency 100%, housing 74 from 20:34, "about 1.3 crossbows a minute" for the four fletchers, and the last raise costing 16 points for roughly 150 gold: 50 to 34, with +150 at 32:39 and +190 at the end). Two statements do not. Food did not hold back popularity or population as it says: no reading lists a negative food factor, taxes were the only negative one, and the population fell when popularity went under 50. Batching was not learned late: the first call asked for four placements, and calls averaged 3.1. The "20 people" idle holds at 24:51 and 30:40 (20, 19) but not at the end (7), and "tax income cost more than it brought" is not checked, since total tax gold is not logged.

For the harness

• The granary line. The rules' Start paragraph says to place the required granary; the save has one (docs/benchmark.md). Here no call tried: its first reasoning saw it built.
• find_sites spots refused for the signpost. At 13:43 three of the four hovel spots it listed near (440, 340) were refused "Too close to signpost", though docs/tools.md says the tile map holds the no-build zone. Spots on plain ground west of the keep (14:49, 20:13) were accepted.
• Ore spots from other searches. The iron_ore group in a hovel's or a fletcher's search lists building-sized spots on ore ground; the three refused mines used them, and the refusal's remedy named a mine search the model did not run.
• Storage fills without a warning. 0 empty piles at 32:39 (3 at 30:40), expand_storage unused since 4:57; the wait warnings cover popularity, food and gold only.
• A repeated request. Its 1.5.1 interview also asked to reach the marketplace's auto-sell through a tool; the game has the setting, the harness has no tool.
• The game saved correctly at the end ("claude opus 5-5 1-7-3 5aa574").