Game automation: the agent's hands and eyes

The real game is the oracle. The loop is launch → navigate → set up the scene → act → screenshot and read logs → decide. Build it once per game, then every change you make can be checked in a minute.

Windows (native or from WSL): fsgc win

fsgc win setup                                   # once: PowerShell tools + finds an ffmpeg with gfxcapture (FSGC_FFMPEG_WIN, or downloads FSGC_FFMPEG_URL), picks NVENC/AMF/QSV/x264
fsgc win ps                                      # windowed processes: pid, name, title
fsgc win launch --steam 105600                   # or: fsgc win launch "C:\Games\Foo\Foo.exe" -- -windowed
fsgc win shot --exe Terraria.exe shot.png --scale 0.33   # full frame + a 1/3 copy that's cheap to look at
fsgc win drive --proc Terraria "focus" "click 640 360" "key 0x1B" "type hello" "hold 0x44 1500"
fsgc win drive --proc Terraria idle              # seconds since the user last touched mouse/keyboard
fsgc win kill <pid>                              # exact PID only
fsgc win reg get "HKCU\Software\..."             # registry (reg set backs the key up first)

From Python (for longer scripts), from game_changer.win import Drive, shot, Recorder, then d = Drive("AoE2DE_s"), d.focus(), d.click(x, y), d.key("0x0D").

WinDrive commands (game_changer/ps1/WinDrive.ps1; stdin protocol, one reply per line). Coordinates are in the game window's client area.

• Mouse: move x y, click x y [right], mdown/mup, drag x0 y0 x1 y1, rel dx dy (FPS cameras / raw input), wheel 120.
• Keyboard: key <vk> [tap|down|up], hold <vk> <ms>, type <text>, scanmode on (DirectInput / raw-input games that ignore virtual-key events).
• Window: focus, rect, size <w> <h> (sets the client size), title, fg, idle, untop.
• Virtual-key codes: Esc 0x1B, Enter 0x0D, Space 0x20, W/A/S/D 0x57/0x41/0x53/0x44, F1 0x70, Shift 0x10, Ctrl 0x11, arrows 0x25-0x28.

Rules of the road

• Never focus a game with an online mode while the human is typing. It happened with GTA V: the agent focused GTA to click Story Mode, the human's keystrokes hit GTA's landing page, and GTA warned about "accessing GTA Online servers with an altered version". ScriptHookV blocked it; don't rely on that. Check idle, ask the human to click, and launch with the anti-cheat off so online can't start. See knowledge/techniques/driving-real-games-safely.md.
• Input only goes to the game. WinDrive refuses to send while another app is in the foreground. The one exception is when nothing is and the cursor is over the game, which windowed games cause by dropping the foreground on clicks.
• The user may be at the PC. If idle is under a minute, ask before driving, and keep sessions short. Unattended runs are fine once the user says so.
• Screenshots cost tokens. Look at --scale 0.33 copies. Multiply coordinates back ×3 for clicks, and keep a table of menu click points in MODLOG.md, measured once.
• Why gfxcapture: GPU-rendered games come out black with GDI capture. gfxcapture (Windows.Graphics.Capture) grabs one window's real frames, even when covered. It can't capture minimized windows.

Make the window predictable

• Windowed mode at a fixed client size. Every game hides this setting somewhere:
  • an ini ([/Script/Engine.GameUserSettings] in UE GameUserSettings.ini, Unity's Screenmanager Fullscreen mode / Resolution registry values under HKCU\Software\<company>\<product>);
  • a launch flag (-windowed -w 1920 -h 1080, Unity -screen-fullscreen 0 -screen-width 1920 -screen-height 1080, Source -sw -w 1920 -h 1080);
  • or the game's own registry (AoE2: Mode Display 0 + Windowed Width/Height).
  • fsgc win drive --proc X "size 1920 1080" also resizes most windowed games.
• Skip intros: launch flags (-skipintro, -nosplash, Unity -popupwindow), or delete/rename intro videos in a copy of the game.
• Jump straight in: loader flags (tModLoader -skipselect Player:World), a save made for testing, scenario auto-load, a dev console command.
• Background throttling: many games throttle or pause unfocused. Find the setting (Terraria: Main.instance.InactiveSleepTime = TimeSpan.Zero; Unity: Application.runInBackground = true; UE: t.IdleWhenNotForeground 0).

Better than clicking: a scripted scene or a bridge

• Chat or console commands in your mod give items, spawn enemies and teleport. They make tests one line (/arsenal, /mothership).
• Test scenes: a mod-side timeline (spawn waves at frame N, fire at N+30), a scenario with triggers (AoE2 via AoE2ScenarioParser), a dedicated test world with a pristine backup.
• Agent bridge: a JSON-lines socket inside the mod on 127.0.0.1 (see examples/terraria-tmodloader/reference/AgentBridge.cs).
  • Commands like observe (menu options or world state as text), click <id>, controls, step.
  • Handle every request on the game's main thread after an update, so replies are consistent.
  • Read menus generically from the UI tree, so the agent sees what a player would. Leave destructive buttons (delete) out.
  • An agent can then play without pixels at all.
• Out-of-process backend: keep the in-game part thin and put the brains outside (HTTP/file-drop). That pattern scales to AI NPCs and cross-game mashups.

Crashes and cleanup

• Crash reporters (BugSplat BsSndRpt64.exe, CrashReportClient.exe, UnityCrashHandler64.exe) can linger and make Steam say "already running". fsgc win ps to spot them, fsgc win kill <pid> to clear them.
• Never pkill -f or wildcard taskkill /IM. The pattern can match your own shell or other apps.
• After a crash, read the loader or game log first (the mod-any-game skill lists them), then the Windows Event Viewer (Application log) for native crashes.

Linux and macOS

• Linux (X11): xdotool search --name "Game" windowactivate --sync key Escape, xdotool mousemove --window $W 640 360 click 1. Screenshots: import -window $(xdotool search --name Game) shot.png, or ffmpeg x11grab.
• Linux (Wayland): ydotool + grim. Proton games are Windows games under Wine: launch options (WINEDLLOVERRIDES, PROTON_LOG=1) go in Steam.
• macOS: screencapture -l <windowid> shot.png (window id via GetWindowID or AppleScript), osascript / cliclick for input. Input and screen recording need Accessibility and Screen Recording permission for the terminal.