--- title: "GPT-5.6 Terra plays Detroit 1972 (seed 1) | Micropolis run | Evals by Jetty" url: https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1.html description: "GPT-5.6 Terra as mayor in Micropolis, Detroit 1972: crime: lost, city score 597. Timelapse, charts, every decision and the run's evaluation." updated: 2026-09-28 publisher: Jetty (https://jetty.io) --- 02 — Run · Round 1 · Detroit 1972: crime · gpt56terra-detroit-s1 # GPT-5.6 Terra plays Detroit 1972 Detroit's crime is out of control in 1972. Bring average crime under 60 in 10 years, without emptying the city. Ended Jan 1982: lost, city score 597. [Decision log](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1/decisions.jsonl)[City stats (CSV)](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1/series.csv)[Save file (.cty)](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1/city.cty)[Final map (PNG)](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1/final_map.png)[Runtime config](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1/runtime_config.json)[Validation report](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1/validation_report.json) GOAL MISSED seed 1 GPT-5.6 Terra openai/gpt-5.6-terra LOST: Average crime 33 (goal < 60), population 6,120 (floor 25,000); engine verdict: won Population (start → end)76,160 → 6,120 Peak population76,160City score (start → end)285 → 597 Funds at the end$23Crime / pollution / traffic33 / 48 / 0 Zones R / C / I142 / 64 / 85 Power plants (coal / nuclear)3 / 1Police / fire stations8 / 2 Turns (model / failed)40 (40 / 0) Actions applied / rejected189 / 13 Mean turn latency14.4sModel cost$1.065Wall clock9.8 min Jetty run ID175f2d53 ## 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 1972 | 76,160 | $20,000 | 285 | 92 | 65 | | 1 | Apr 1972 | 73,280 | $15,422 | 530 | 92 | 65 | | 2 | Jul 1972 | 67,960 | $14,298 | 530 | 73 | 64 | | 3 | Oct 1972 | 59,800 | $13,278 | 530 | 70 | 62 | | 4 | Jan 1973 | 55,860 | $10,008 | 427 | 70 | 62 | | 5 | Apr 1973 | 48,640 | $9,915 | 427 | 63 | 59 | | 6 | Jul 1973 | 43,960 | $8,782 | 427 | 52 | 56 | | 7 | Oct 1973 | 38,220 | $8,197 | 427 | 52 | 56 | | 8 | Jan 1974 | 33,980 | $7,436 | 350 | 44 | 56 | | 9 | Apr 1974 | 29,500 | $7,436 | 350 | 41 | 49 | | 10 | Jul 1974 | 26,960 | $7,436 | 350 | 41 | 50 | | 11 | Oct 1974 | 22,940 | $7,280 | 350 | 36 | 50 | | 12 | Jan 1975 | 20,360 | $6,049 | 326 | 33 | 46 | | 13 | Apr 1975 | 17,980 | $5,948 | 326 | 33 | 43 | | 14 | Jul 1975 | 16,420 | $5,873 | 326 | 52 | 43 | | 15 | Oct 1975 | 14,980 | $5,857 | 326 | 48 | 44 | | 16 | Jan 1976 | 14,420 | $4,332 | 346 | 48 | 46 | | 17 | Apr 1976 | 13,680 | $4,332 | 346 | 45 | 46 | | 18 | Jul 1976 | 12,860 | $3,998 | 346 | 42 | 46 | | 19 | Oct 1976 | 12,280 | $988 | 346 | 42 | 45 | | 20 | Jan 1977 | 11,520 | $303 | 383 | 38 | 45 | | 21 | Apr 1977 | 10,580 | $303 | 383 | 37 | 45 | | 22 | Jul 1977 | 9,500 | $303 | 383 | 37 | 46 | | 23 | Oct 1977 | 8,860 | $303 | 383 | 36 | 43 | | 24 | Jan 1978 | 8,560 | $197 | 420 | 35 | 43 | | 25 | Apr 1978 | 7,840 | $197 | 420 | 35 | 44 | | 26 | Jul 1978 | 7,700 | $197 | 420 | 35 | 45 | | 27 | Oct 1978 | 7,420 | $197 | 420 | 34 | 44 | | 28 | Jan 1979 | 6,380 | $197 | 401 | 34 | 44 | | 29 | Apr 1979 | 6,080 | $197 | 401 | 34 | 48 | | 30 | Jul 1979 | 5,620 | $197 | 401 | 32 | 45 | | 31 | Oct 1979 | 5,480 | $197 | 401 | 32 | 45 | | 32 | Jan 1980 | 6,220 | $197 | 515 | 32 | 46 | | 33 | Apr 1980 | 8,680 | $89 | 515 | 32 | 47 | | 34 | Jul 1980 | 8,840 | $89 | 515 | 32 | 48 | | 35 | Oct 1980 | 7,960 | $89 | 515 | 35 | 48 | | 36 | Jan 1981 | 7,180 | $761 | 508 | 34 | 45 | | 37 | Apr 1981 | 6,520 | $761 | 508 | 34 | 44 | | 38 | Jul 1981 | 5,460 | $761 | 508 | 33 | 44 | | 39 | Oct 1981 | 5,320 | $23 | 508 | 33 | 46 | | 40 | Jan 1982 | 6,960 | $23 | 597 | 33 | 48 | ## Final map [![Final city map: GPT-5.6 Terra on Detroit 1972: crime](https://evaljetty.com/micropolis/media/gpt56terra-detroit-s1-map.jpg)](https://evaljetty.com/micropolis/runs/gpt56terra-detroit-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 1982 after 40 turns; scenario verdict True | | pass | code\_check | decisions-logged | 40 rows for 40 turns | | pass | code\_check | llm-turns-valid | 0/40 model turns failed | | pass | code\_check | video-decodes | duration 36.9s | | pass | code\_check | limits-respected | 9.8 wall-minutes (model budget 45.0 min) | | fail | judge | scenario-goal | LOST: Average crime 33 (goal < 60), population 6,120 (floor 25,000); engine verdict: won (score 0 / threshold 1) | | pass | checklist | notes-explain-outcome | summary.md Notes section cites turn 1 police strategy, turn 20 power crisis pivot, turns 28-30 bankruptcy, and final turn concession on population target | | pass | checklist | player-matches-request | result.json shows player=gpt56terra model=openai/gpt-5.6-terra task=detroit seed=1 matching the runbook parameters | | pass | checklist | no-silent-outage | run.log shows 40 consecutive successful turns with 0 LLM failures; no gaps or error stretches observed | ## Decision timeline What the mayor thought and did each turn. Click a turn to jump the timelapse there. --- Source: https://evaljetty.com/micropolis/runs/gpt56terra-detroit-s1.html · Evals by Jetty · Run your own evals: https://jetty.io/?utm_source=evaljetty&utm_medium=llms