cities-skylines1-agent-skill - SKILL.md Agent Skill

name: cities-skylines1-agent-skill description: "Operate Cities: Skylines 1 through the Skylines Agent Bridge mod and localhost API. Use when Codex needs to build, inspect, repair, resume, save, or continue a CS1 city using focused API calls rather than screenshot recognition, including road connectivity, service infrastructure, zoning, facilities, problem icons, and save verification."

Cities: Skylines 1 Agent Skill

Use this skill to control a running Cities: Skylines 1 city through the local Skylines Agent Bridge API.

Core Rules

Prefer API state over image recognition.
Resume and repair existing saves by default. Start fresh only when explicitly requested.
Use small, separated commands: inspect, bulldoze, build, place, move, zone, simulate, save.
Save after meaningful city changes and verify the .crp file exists.
Commit repository changes after each coherent code/docs task when working inside this repository.

Local Setup

The bridge listens on:

http://127.0.0.1:32123

Build and install the mod:

powershell -NoProfile -ExecutionPolicy Bypass -File .\scripts\build.ps1

Resume the latest save:

powershell -NoProfile -ExecutionPolicy Bypass -File .\scripts\start-resume.ps1

Start a new map only when the user asks:

powershell -NoProfile -ExecutionPolicy Bypass -File .\scripts\start-new-map.ps1

Inspection Loop

Use these before acting:

Invoke-RestMethod http://127.0.0.1:32123/health
Invoke-RestMethod http://127.0.0.1:32123/state/summary
Invoke-RestMethod "http://127.0.0.1:32123/state/chirps?limit=50"
Invoke-RestMethod http://127.0.0.1:32123/state/zones
Invoke-RestMethod "http://127.0.0.1:32123/state/problems?limit=200"
Invoke-RestMethod "http://127.0.0.1:32123/state/economy"
Invoke-RestMethod "http://127.0.0.1:32123/state/road-anomalies?limit=500&nearMissDistance=18&shortSegmentLength=32&includeDeadEnds=false"
Invoke-RestMethod "http://127.0.0.1:32123/state/building-anomalies?limit=200"
Invoke-RestMethod "http://127.0.0.1:32123/state/zone-anomalies?limit=200&includeUnzonedHoles=true"
Invoke-RestMethod "http://127.0.0.1:32123/state/facilities?limit=500"
Invoke-RestMethod "http://127.0.0.1:32123/state/growables?limit=500"
Invoke-RestMethod "http://127.0.0.1:32123/state/networks?limit=1000&service=Road"

Use includeMapObjects=true on /state/facilities only when raw helper objects such as pipe junctions are needed.

Command Pattern

Use separate commands so the repair remains auditable.

Delete a bad segment:

$body = @{ entityType = "netSegment"; id = 19023; keepNodes = $false } | ConvertTo-Json
Invoke-RestMethod -Method Post -Uri http://127.0.0.1:32123/commands/bulldoze -Body $body -ContentType "application/json"

Build a network segment:

$body = @{
  roadPrefab = "Basic Road"
  start = @{ x = 400; z = 300 }
  end = @{ x = 423.614; z = 554.945 }
  name = "Agent Highway Link"
} | ConvertTo-Json -Depth 5
Invoke-RestMethod -Method Post -Uri http://127.0.0.1:32123/commands/build-network -Body $body -ContentType "application/json"

Place or move a building:

$body = @{ buildingPrefab = "Water Tower"; position = @{ x = 120; z = -220 }; angleDegrees = 0 } | ConvertTo-Json -Depth 5
Invoke-RestMethod -Method Post -Uri http://127.0.0.1:32123/commands/place-building -Body $body -ContentType "application/json"

Paint zones:

$body = @{ zone = "ResidentialLow"; preserveOccupied = $true; center = @{ x = 240; z = -40 }; radius = 70 } | ConvertTo-Json -Depth 5
Invoke-RestMethod -Method Post -Uri http://127.0.0.1:32123/commands/set-zone -Body $body -ContentType "application/json"

Run simulation:

$body = @{ paused = $false; speed = 3 } | ConvertTo-Json
Invoke-RestMethod -Method Post -Uri http://127.0.0.1:32123/commands/set-simulation-speed -Body $body -ContentType "application/json"

Lower taxes when /state/problems reports TaxesTooHigh:

$body = @{ service = "Commercial"; rate = 9 } | ConvertTo-Json
Invoke-RestMethod -Method Post -Uri http://127.0.0.1:32123/commands/set-tax-rate -Body $body -ContentType "application/json"

Save and verify:

powershell -NoProfile -ExecutionPolicy Bypass -File .\scripts\save-city.ps1 -Name AgentAutoSave-clean
Invoke-RestMethod http://127.0.0.1:32123/state/saves

Known Gotchas

CS1 network crossings are not intersections unless a real node is created. If a pipe or road visually crosses another segment but does not connect, bulldoze and rebuild split segments with a shared endpoint.
Heating service buildings may create an actual connection helper offset from the building center. Query /state/facilities?service=Water&includeMapObjects=true when diagnosing heating pipe issues.
Roads that look connected to highways can still have separate nodes. Use /state/road-anomalies and rebuild with endpoints close enough to reuse the existing road nodes.
Do not treat all dead ends as errors. Use bounded checks or includeDeadEnds=false unless the user asks to remove cul-de-sacs/stubs.
Use /state/zone-anomalies when zone colors look mottled or circular paint left residential/commercial/industrial/office cells mixed in the same block.
/commands/set-zone defaults to preserveOccupied=true; check /state/growables first and keep that flag enabled unless the user explicitly wants to repaint developed blocks.
If screenshots show blue/green/yellow mottling across a whole city block, use /state/zone-anomalies and repair with /commands/repair-zone-clusters using preferGrowableZone=true.