--- title: "GPT-5.6 Luna plays Tokyo 1957 (seed 1) | Micropolis run | Evals by Jetty" url: https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1.html description: "GPT-5.6 Luna as mayor in Micropolis, Tokyo 1957: monster attack: lost, city score 330. Timelapse, charts, every decision and the run's evaluation." updated: 2026-09-28 publisher: Jetty (https://jetty.io) --- 02 — Run · Round 1 · Tokyo 1957: monster attack · gpt56luna-tokyo-s1 # GPT-5.6 Luna plays Tokyo 1957 A monster attacks Tokyo in 1957. Rebuild and get the city score above 500 within 5 years. Ended Jan 1962: lost, city score 330. [Decision log](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/decisions.jsonl)[City stats (CSV)](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/series.csv)[Save file (.cty)](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/city.cty)[Final map (PNG)](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/final_map.png)[Runtime config](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/runtime_config.json)[Validation report](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/validation_report.json) GOAL MISSED seed 1 GPT-5.6 Luna openai/gpt-5.6-luna LOST: City score 330 (goal > 500); engine verdict: lost Population (start → end)113,100 → 23,700 Peak population113,100City score (start → end)500 → 330 Funds at the end$0Crime / pollution / traffic21 / 53 / 7 Zones R / C / I133 / 92 / 88 Power plants (coal / nuclear)7 / 0Police / fire stations18 / 12 Turns (model / failed)20 (20 / 0) Actions applied / rejected144 / 37 Mean turn latency7.3sModel cost$0.044Wall clock2.5 min Jetty run ID4675adce ## The city over time ### Population People, after every turn ### Funds Treasury, after every turn ### City score 0–1000, re-evaluated each January Table view | Turn | Date | Population | Funds | City score | Crime | Pollution | | --- | --- | --- | --- | --- | --- | --- | | 0 | Jan 1957 | 113,100 | $20,000 | 500 | 31 | 61 | | 1 | Apr 1957 | 110,660 | $16,954 | 677 | 31 | 61 | | 2 | Jul 1957 | 107,720 | $16,290 | 677 | 73 | 65 | | 3 | Oct 1957 | 104,460 | $14,784 | 677 | 78 | 71 | | 4 | Jan 1958 | 100,620 | $10,948 | 639 | 78 | 71 | | 5 | Apr 1958 | 98,800 | $10,901 | 639 | 76 | 72 | | 6 | Jul 1958 | 92,280 | $9,959 | 639 | 67 | 70 | | 7 | Oct 1958 | 86,680 | $9,869 | 639 | 67 | 70 | | 8 | Jan 1959 | 79,980 | $6,614 | 501 | 60 | 69 | | 9 | Apr 1959 | 74,200 | $6,603 | 501 | 55 | 70 | | 10 | Jul 1959 | 67,900 | $5,984 | 501 | 55 | 67 | | 11 | Oct 1959 | 61,820 | $5,929 | 501 | 48 | 67 | | 12 | Jan 1960 | 56,580 | $0 | 408 | 43 | 61 | | 13 | Apr 1960 | 51,060 | $0 | 408 | 43 | 60 | | 14 | Jul 1960 | 45,600 | $0 | 408 | 37 | 60 | | 15 | Oct 1960 | 40,880 | $0 | 408 | 32 | 60 | | 16 | Jan 1961 | 37,660 | $1,068 | 357 | 32 | 61 | | 17 | Apr 1961 | 32,980 | $919 | 357 | 29 | 57 | | 18 | Jul 1961 | 29,680 | $549 | 357 | 25 | 57 | | 19 | Oct 1961 | 26,380 | $486 | 357 | 25 | 57 | | 20 | Jan 1962 | 23,020 | $0 | 330 | 21 | 53 | ## Final map [![Final city map: GPT-5.6 Luna on Tokyo 1957: monster attack](https://evaljetty.com/micropolis/media/gpt56luna-tokyo-s1-map.jpg)](https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1/final_map.png) ## Evaluation failchecks **9/10** verdict: valid run (code checks and checklist) and task goal met (judge) | Status | Kind | Check | Detail | | --- | --- | --- | --- | | pass | step | environment | Environment check (snapshot, engine, key) | | pass | step | launch | Launch run-city as a detached process | | pass | step | supervise | Supervise in the foreground until run-city exits | | pass | step | render | Timelapse video rendered | | pass | step | notes | Append Notes to summary.md | | pass | code\_check | outputs-exist | all present | | pass | code\_check | sim-reached-deadline | ended Jan 1962 after 20 turns; scenario verdict False | | pass | code\_check | decisions-logged | 20 rows for 20 turns | | pass | code\_check | llm-turns-valid | 0/20 model turns failed | | pass | code\_check | video-decodes | duration 30.0s | | pass | code\_check | limits-respected | 2.5 wall-minutes (model budget 45.0 min) | | fail | judge | scenario-goal | LOST: City score 330 (goal > 500); engine verdict: lost (score 0 / threshold 1) | | pass | checklist | notes-explain-outcome | Notes section added citing model thoughts from turns 1, 8, and 20 explaining the population collapse and budget failure | | pass | checklist | player-matches-request | result.json confirms player=gpt56luna, task=tokyo, seed=1 matching the request | | pass | checklist | no-silent-outage | run.log shows 20 continuous turns with 0 LLM failures and no gaps in turn logging | ## Decision timeline What the mayor thought and did each turn. Click a turn to jump the timelapse there. --- Source: https://evaljetty.com/micropolis/runs/gpt56luna-tokyo-s1.html · Evals by Jetty · Run your own evals: https://jetty.io/?utm_source=evaljetty&utm_medium=llms