---
title: "GPT-5.6 Luna plays Detroit 1972 (seed 2) | Micropolis run | Evals by Jetty"
url: https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2.html
description: "GPT-5.6 Luna as mayor in Micropolis, Detroit 1972: crime: lost, city score 704. 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 · gpt56luna-detroit-s2

# GPT-5.6 Luna 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 704.

[Decision log](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/decisions.jsonl)[City stats (CSV)](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/series.csv)[Save file (.cty)](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/city.cty)[Final map (PNG)](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/final_map.png)[Runtime config](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/runtime_config.json)[Validation report](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/validation_report.json)

GOAL MISSED seed 2

GPT-5.6 Luna

openai/gpt-5.6-luna

LOST: Average crime 30 (goal < 60), population 15,280 (floor 25,000); engine verdict: won

Population (start → end)76,160 → 15,280
Peak population76,320City score (start → end)285 → 704
Funds at the end$6Crime / pollution / traffic30 / 49 / 2
Zones R / C / I146 / 64 / 95
Power plants (coal / nuclear)2 / 3Police / fire stations18 / 7
Turns (model / failed)40 (40 / 0)
Actions applied / rejected241 / 60
Mean turn latency7.9sModel cost$0.087Wall clock5.4 min
Jetty run IDaba6000b

## 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 | 68 |
| 1 | Apr 1972 | 76,320 | $16,324 | 537 | 92 | 68 |
| 2 | Jul 1972 | 72,940 | $15,035 | 537 | 95 | 66 |
| 3 | Oct 1972 | 67,580 | $13,797 | 537 | 102 | 64 |
| 4 | Jan 1973 | 61,240 | $10,284 | 458 | 102 | 64 |
| 5 | Apr 1973 | 57,280 | $9,235 | 458 | 86 | 63 |
| 6 | Jul 1973 | 51,960 | $9,035 | 458 | 79 | 59 |
| 7 | Oct 1973 | 47,140 | $7,424 | 458 | 79 | 59 |
| 8 | Jan 1974 | 42,460 | $3,717 | 386 | 69 | 54 |
| 9 | Apr 1974 | 39,220 | $3,053 | 386 | 63 | 51 |
| 10 | Jul 1974 | 35,420 | $2,933 | 386 | 63 | 51 |
| 11 | Oct 1974 | 32,260 | $2,823 | 386 | 58 | 51 |
| 12 | Jan 1975 | 28,820 | $1,683 | 345 | 53 | 47 |
| 13 | Apr 1975 | 25,540 | $1,683 | 345 | 53 | 43 |
| 14 | Jul 1975 | 23,000 | $1,137 | 345 | 47 | 43 |
| 15 | Oct 1975 | 20,620 | $1,102 | 345 | 43 | 46 |
| 16 | Jan 1976 | 18,200 | $265 | 319 | 43 | 45 |
| 17 | Apr 1976 | 16,160 | $250 | 319 | 40 | 43 |
| 18 | Jul 1976 | 14,460 | $186 | 319 | 38 | 43 |
| 19 | Oct 1976 | 12,480 | $181 | 319 | 38 | 40 |
| 20 | Jan 1977 | 10,840 | $0 | 307 | 37 | 45 |
| 21 | Apr 1977 | 9,740 | $0 | 307 | 35 | 45 |
| 22 | Jul 1977 | 7,880 | $0 | 307 | 35 | 44 |
| 23 | Oct 1977 | 6,560 | $0 | 307 | 33 | 42 |
| 24 | Jan 1978 | 6,600 | $0 | 309 | 33 | 42 |
| 25 | Apr 1978 | 6,280 | $0 | 309 | 33 | 44 |
| 26 | Jul 1978 | 6,700 | $0 | 309 | 32 | 44 |
| 27 | Oct 1978 | 9,760 | $0 | 309 | 34 | 45 |
| 28 | Jan 1979 | 9,640 | $323 | 654 | 34 | 45 |
| 29 | Apr 1979 | 8,580 | $323 | 654 | 36 | 48 |
| 30 | Jul 1979 | 7,700 | $114 | 654 | 35 | 47 |
| 31 | Oct 1979 | 6,620 | $10 | 654 | 35 | 47 |
| 32 | Jan 1980 | 5,680 | $186 | 464 | 34 | 48 |
| 33 | Apr 1980 | 5,220 | $119 | 464 | 32 | 51 |
| 34 | Jul 1980 | 4,460 | $13 | 464 | 32 | 53 |
| 35 | Oct 1980 | 4,400 | $13 | 464 | 31 | 53 |
| 36 | Jan 1981 | 4,260 | $160 | 409 | 30 | 53 |
| 37 | Apr 1981 | 3,760 | $95 | 409 | 30 | 52 |
| 38 | Jul 1981 | 4,260 | $22 | 409 | 30 | 52 |
| 39 | Oct 1981 | 9,340 | $6 | 409 | 30 | 48 |
| 40 | Jan 1982 | 16,440 | $6 | 704 | 30 | 49 |

## Final map

[![Final city map: GPT-5.6 Luna on Detroit 1972: crime](https://evaljetty.com/micropolis/media/gpt56luna-detroit-s2-map.jpg)](https://evaljetty.com/micropolis/runs/gpt56luna-detroit-s2/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 | 5.4 wall-minutes (model budget 45.0 min) |
| fail | judge | scenario-goal | LOST: Average crime 30 (goal < 60), population 15,280 (floor 25,000); engine verdict: won (score 0 / threshold 1) |
| pass | checklist | notes-explain-outcome | Notes section added to summary.md citing model thoughts from turns 1, 8, and 40 |
| pass | checklist | player-matches-request | result.json confirms player=gpt56luna, model=openai/gpt-5.6-luna, task=detroit, seed=2 |
| pass | checklist | no-silent-outage | 0 LLM failures across all 40 turns, run.log shows only the expected scenario-goal JSON at exit |

## 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-detroit-s2.html · Evals by Jetty · Run your own evals: https://jetty.io/?utm_source=evaljetty&utm_medium=llms