Sys is an engine namespace: implemented natively by the game engine, not by any decompiled .lua module. There is no source file behind it, no import() needed — it is always globally available from any script. It is a general system-services grab-bag covering time/clock utilities, save/autosave control, asset preloading, level and shell state, platform/build/SKU queries, GUID string conversion, and a scattering of miscellaneous system settings (rumble, subtitles, Y-axis inversion, HUD/viewport toggles).
Provenance
The 64 functions listed below are a complete, authoritative enumeration taken from a live pairs(Sys) dump in-game — every name here is confirmed to exist. That dump gives names and raw function pointers only, nothing about parameters or behavior. Everything beyond that (argument shapes, likely purpose) is inferred from real call sites in the ~230 decompiled .lua files; where no call site exists anywhere in that corpus, this page says so explicitly rather than guessing.
Functions
Time & Clock
Function
Signature (best-known)
Notes
RealTimeStamp
uStamp = Sys.RealTimeStamp()
Used with no arguments in real scripts to capture a timestamp handle, e.g. uLockTimer = Sys.RealTimeStamp() (resident/antiair.lua:279), later read via TimeStampGetElapsed.
MainTimeStamp
uStamp = Sys.MainTimeStamp()
Used the same way as RealTimeStamp, e.g. _uSessionStartTimestamp = Sys.MainTimeStamp() (resident/mrxplaystate.lua:111), tTimeStamp[uWeapon] = Sys.MainTimeStamp() (resident/mrxstatsmanager.lua:501,575), self._uTimeStamp = Sys.MainTimeStamp() (resident/mrxtaskrace.lua:268). Distinct from RealTimeStamp — presumably tied to the “main” (pausable/scaled) clock rather than a real-world clock, consistent with the separate MainTime/RealTime accessors below, but the exact difference is not confirmed from source.
TimeStampMark
Sys.TimeStampMark(uStamp)
Used to reset/re-mark an existing timestamp handle in place, e.g. Sys.TimeStampMark(tTimeStamp[uWeapon]) (resident/mrxstatsmanager.lua:499), Sys.TimeStampMark(self._uTimeStamp) (resident/mrxtaskrace.lua:269) — call sites consistently re-mark a stamp previously produced by MainTimeStamp/RealTimeStamp rather than creating a new one.
TimeStampGetElapsed
n = Sys.TimeStampGetElapsed(uStamp)
Confirmed pervasively: nBlink = Sys.TimeStampGetElapsed(tLockOn.uLockTimer) * nRate (resident/antiair.lua:350), nThisSession = Sys.TimeStampGetElapsed(_uSessionStartTimestamp) (resident/mrxplaystate.lua:102), resident/mrxstatsmanager.lua:490,564, resident/mrxtaskrace.lua:277. Returns elapsed seconds since the stamp was marked. This — plus MainTimeStamp/TimeStampMark — is the real building-block pattern used for elapsed-time tracking in this codebase, a lower-level alternative to the callback-based Event.TimerRelative pattern for cases that need to poll elapsed time rather than fire once after a delay.
MainTime
n = Sys.MainTime()
Used with no arguments, e.g. return Sys.MainTime() (resident/mrxplaystate.lua:106) as a fallback session-time source. Presumed to be the game’s internal (pausable/scaled) clock in seconds, paired conceptually with MainTimeStamp above, but the precise semantics (does it stop on pause? is it time-scaled by SetTimeScale?) are not confirmed from source.
RealTime
n = Sys.RealTime()
Live-confirmed via WebSocket lua-bridge probe against a running game (2026-07-22): callable with no arguments, returns a plain number — no longer “no call sites found / unconfirmed.” The specific unit/epoch isn’t confirmed, but a confirmed numeric return is consistent with the presumed role as the real-world-clock counterpart to MainTime, paired with RealTimeStamp.
Clock
n = Sys.Clock()
Live-confirmed via WebSocket lua-bridge probe against a running game (2026-07-22): callable with no arguments, returns a plain number — no longer “no call sites found / unconfirmed.” Purpose beyond “a number” (raw tick count vs. clock-seconds reading) is still not confirmed.
Time
n = Sys.Time()
Live-confirmed via WebSocket lua-bridge probe against a running game (2026-07-22): callable with no arguments, returns a plain number. Grouped here with RealTime/Clock above — the live probe found all three returning the same “number” shape.
Date
s = Sys.Date()
Live-confirmed via WebSocket lua-bridge probe against a running game (2026-07-22): callable with no arguments, returns a string in MM/DD/YY HH:MM:SS format — no longer “no call sites found / unconfirmed.” Unlike its numeric Time & Clock siblings here, this one returns a formatted date/time string, not a number.
DiffTime
—
No call sites found in the decompiled corpus. Exists per live enumeration; presumed to compute a difference between two time/timestamp values by naming, unconfirmed.
SetTimeScale
Sys.SetTimeScale(nScale)
Confirmed: Sys.SetTimeScale(Math.min(nNewTimeScale, nMinTimeScale)) (resident/hero.lua:249) — used for a slow-motion-style effect, clamped to a minimum scale before being applied.
Confirmed with 4 arguments: Sys.RequestAutosave(inMission, lastMission, fMissionTime, MrxStatsManager.GetPercentCompleted()) (resident/mrxmissionflow.lua:768). Also guarded defensively elsewhere: if Sys.RequestAutosave and _bDoMissionAutosave then (resident/mrxmissionflow.lua:825), confirming it’s an optional/late-bound engine entry point checked for existence before use, same pattern seen for several other Sys functions below.
ForceNextAutosave
Sys.ForceNextAutosave()
Used with no arguments: Sys.ForceNextAutosave() (vz/wifmissionflow.lua:463).
IsAutosaveEnabled
—
No call sites found in the decompiled corpus. Exists per live enumeration; presumed getter counterpart to SetAutosaveEnabled, unconfirmed.
SetAutosaveEnabled
—
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
SetLuaSaveVersion
Sys.SetLuaSaveVersion(nVersion)
Confirmed: Sys.SetLuaSaveVersion(GetSaveDataVersion()) (shell/shellbootstrap.lua:68, resident/gamebootstrap.lua:41) — always called with the return value of a local GetSaveDataVersion() helper, run once during bootstrap.
RequestGameState
Sys.RequestGameState(sState)
Extremely widely used with a single state-name string, e.g. "Shell", "ingame", "cinematic", "Pause", "attract", "Exiting", "LTI_precache", "Loading", "unloading", "waitfortether", "WaitForStreaming", "WaitForTether", "PDA" (dozens of call sites across shell/mrxguishell.lua, resident/mrxstate.lua, resident/levelbootstrap.lua, vz/wifmissionflow.lua, and others). This is the core game-state transition request function; state names are free-form strings matched against whatever state machine the engine runs natively — not enumerated anywhere as constants. resident/mrxutil.lua:113,132 shows it returning a success boolean (local bSuccess = Sys.RequestGameState("waitfortether")).
Level & Shell State
Function
Signature (best-known)
Notes
GetLevelName
s = Sys.GetLevelName()
Very widely used with no arguments, e.g. resident/gamebootstrap.lua:70, resident/levelbootstrap.lua:3, resident/mrxbootstrap.lua:60 (string.lower(Sys.GetLevelName())), resident/mrxplayer.lua:408 (compared against "vz").
SetLevelName
Sys.SetLevelName(sLevelName)
Confirmed: Sys.SetLevelName(LevelName) (resident/levelbootstrap.lua:8), paired with GetLevelName reads earlier in the same file.
GetMasterScriptName
s = Sys.GetMasterScriptName()
Confirmed alongside GetLevelName, e.g. shell/mrxguishell.lua:596, resident/gamebootstrap.lua:70, used together to drive Net.StartServer(...) and LevelBootstrap.LoadLevel(...) calls.
Used with no arguments: local sShellCode = Sys.GetShellCode() (shell/mrxguishell.lua:549).
FinishedShell
b = Sys.FinishedShell()
Guarded/optional-style call: if Sys.FinishedShell and Sys.FinishedShell() then (resident/gamebootstrap.lua:43).
AutoLoad
b = Sys.AutoLoad()
Used with no arguments as a boolean gate for skipping the shell/menu flow, e.g. if not Sys.AutoLoad() then (shell/mrxguishell.lua:259), elseif Sys.AutoLoad() then (resident/gamebootstrap.lua:65, shell/shellbootstrap.lua:94).
Confirmed with 4 arguments: Sys.RequiredAsset(LevelName .. "_base", "layer", -2, false) and Sys.RequiredAsset(MasterScript, "script", -3, false) (resident/levelbootstrap.lua:14-15) — registers an asset (layer or script) as required for the current level, with a numeric priority (negative in both observed cases) and a trailing boolean whose meaning is not confirmed.
GetSkipMission
s = Sys.GetSkipMission()
Used with no arguments: local sSkipToMissionName = Sys.GetSkipMission() (vz/xQ!L.lua:639).
SetSkipMission
Sys.SetSkipMission(sMissionName)
Confirmed repeatedly with a mission-name string (including an empty-string “clear” call): Sys.SetSkipMission(sMission) (shell/mrxguishell.lua:168), Sys.SetSkipMission("") (vz/xQ!L.lua:640,689), Sys.SetSkipMission(sMissionId) (vz/xQ!L.lua:909).
GetForceNewGame
b = Sys.GetForceNewGame()
Guarded/optional-style call: if Sys.GetForceNewGame and Sys.GetForceNewGame() then (resident/mrxmissionflow.lua:154).
GetINIBriefing
b = Sys.GetINIBriefing()
Widely used with no arguments as a boolean, e.g. shell/mrxguishell.lua:148,165, vz/xQ!L.lua:643.
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
Platform & Build Info
Function
Signature (best-known)
Notes
GetVersion
sCode, sData = Sys.GetVersion()
Confirmed with two return values: local sCode, sData = Sys.GetVersion() (shell/mrxguishell.lua:527).
GetPlatform
n = Sys.GetPlatform()
Used with no arguments: local nPlatform = Sys.GetPlatform() (resident/mrxguipda.lua:118) — treated as a numeric platform ID at the call site, not a string.
GetLanguage
s = Sys.GetLanguage()
Confirmed: sLanguage = Sys.GetLanguage() or "English" (resident/mrxbriefing.lua:1191) — the or "English" fallback suggests it can return nil/falsy on some builds.
IsFinalConfig
b = Sys.IsFinalConfig()
Guarded/optional-style call: if ... Sys.IsFinalConfig and not Sys.IsFinalConfig() then (shell/mrxguishell.lua:311) — gates a debug-only skip button so it’s unavailable in final builds.
IsDemoMode
b = Sys.IsDemoMode()
Guarded/optional-style call: if Sys.IsDemoMode and Sys.IsDemoMode() then (shell/mrxgui.lua:421, shell/mrxgui_shellonly.lua:291).
IsGermanSKU
b = Sys.IsGermanSKU()
Confirmed, called unguarded (unlike most other Is* queries here): if not Sys.IsGermanSKU() then / if Sys.IsGermanSKU() then (resident/mrxtaskobjectiveverify.lua:95,242,404) — gates region-specific content (presumably gore/violence toggles for the German release).
IsLoadingOrStreaming
b = Sys.IsLoadingOrStreaming()
Guarded/optional-style call: if Sys.IsLoadingOrStreaming and (not Player.GetLocalCharacter() or Sys.IsLoadingOrStreaming()) then (vz/wifvzatmosphere.lua:26).
LTIGetPrecacheBypass
n = Sys.LTIGetPrecacheBypass()
Confirmed: if Sys.LTIGetPrecacheBypass() > 0 then (shell/shellbootstrap.lua:58) — returns a number compared against 0, not a plain boolean.
MemUsage
n = Sys.MemUsage()
Live-confirmed via WebSocket lua-bridge probe against a running game (2026-07-22): callable with no arguments, returns a plain number — no longer “no call sites found / unconfirmed,” confirming the presumed memory-diagnostics-query role by naming. Units (bytes/KB/MB) not confirmed.
GetCharacterTemplate
s = Sys.GetCharacterTemplate()
Confirmed as a fallback in a chain: MrxGuiShellBootstrap.GetSelectedCharacter() or Sys.GetCharacterTemplate() or "mattias" (resident/mrxplayer.lua:636) — returns a character-template name string, with "mattias" as the ultimate hardcoded fallback.
HaveActiveProfile
Sys.HaveActiveProfile()
Called with no arguments and its result discarded/unused at the one call site found: Sys.HaveActiveProfile() (resident/mrxguipda.lua:1332) — return value’s use elsewhere is not confirmed.
GetForceNewGame
see Level & Shell State above
Listed once; grouped there since it gates new-game/level-bootstrap flow rather than being a platform query.
Asset Preloading
Function
Signature (best-known)
Notes
GetAssetRequestMax
n = Sys.GetAssetRequestMax()
Confirmed: _knOrigAssetRequestMax = Sys.GetAssetRequestMax() (resident/mrxlayermanager.lua:15), and read again as a comparison bound: elseif nPendingOps > Sys.GetAssetRequestMax() then (resident/mrxlayermanager.lua:200).
SetAssetRequestMax
Sys.SetAssetRequestMax(nMax)
Confirmed paired with the getter: Sys.SetAssetRequestMax(_knOrigAssetRequestMax) to restore the original value, and Sys.SetAssetRequestMax(nPendingOps) to raise it temporarily (resident/mrxlayermanager.lua:197,201) — the asset-streaming throttle used by the layer manager.
RequiredAsset
see Level & Shell State above
Listed once; grouped there since its confirmed call sites are both level-bootstrap related.
DisableAssetPreload
—
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
FlushAssets
—
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
AddStringDb
—
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
ClearStringDb
—
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
GUID Conversion
Function
Signature (best-known)
Notes
GuidToString
s = Sys.GuidToString(uGuid)
Very widely used, e.g. tonumber(Sys.GuidToString(uViewportId)) (shell/mrxguibase.lua:140), Sys.GuidToString(uiStateHashName) (resident/fueltank.lua:2, resident/islandfortress.lua:52-53, resident/oilrig.lua:33), Sys.GuidToString(uGateGuid) (resident/friendlygate.lua:24,36), and repeatedly in resident/mrxtaskcontract.lua, resident/mrxtaskobjective.lua, resident/mrxparkinglotmanager.lua. Converts a uGuid handle to its string form — often used as a table key (e.g. tAdjacencyTable[Sys.GuidToString(uNodeNameHash)] in resident/islandfortress.lua:76) or for debug printing.
StringToGuid
uGuid = Sys.StringToGuid(sGuidString)
Confirmed as the namespaced form: local uVehicle = Sys.StringToGuid(sVehicleGuid) (vz/wifpmcgarage.lua:243), local uGateGuid = Sys.StringToGuid("0x000f9a64") (vz/wiftutorialgatehonk.lua:10). See Notes for modders below — this is very likely the same underlying function as the bare global StringToGuid used pervasively elsewhere.
Misc Settings
Function
Signature (best-known)
Notes
RumbleEnabled
b = Sys.RumbleEnabled()
Used with no arguments: bRumble = Sys.RumbleEnabled() (resident/mrxguipausescreen.lua:238), part of the pause-screen options-menu read of current system settings.
SubtitlesEnabled
b = Sys.SubtitlesEnabled()
Used both guarded and unguarded: if Sys.SubtitlesEnabled and Sys.SubtitlesEnabled() then (shell/mrxguicinematic.lua:391), bSubtitles = Sys.SubtitlesEnabled() (resident/mrxguipausescreen.lua:233).
YAxisInverted
b = Sys.YAxisInverted()
Used with no arguments: bInvert = Sys.YAxisInverted() (resident/mrxguipausescreen.lua:248) — read alongside RumbleEnabled/SubtitlesEnabled in the same pause-screen options read.
IsConfirmOnCircle
b = Sys.IsConfirmOnCircle()
Very widely used, almost always guarded: if Sys.IsConfirmOnCircle and Sys.IsConfirmOnCircle() then (shell/mrxguibase.lua:1910, resident/mrxguihudmessage.lua:513,551, resident/mrxguisatellite.lua:374), and unguarded in resident/mrxbriefing.lua:2996. Region/platform-specific controller-confirm-button convention (PS-style “circle to cancel” vs “cross to confirm”).
NoHud
b = Sys.NoHud()
Used unguarded: if Sys.NoHud() then (shell/mrxguimanager.lua:66, resident/mrxguimanager.lua:66).
Guarded call: if Sys.SetTutorialsEnabled then Sys.SetTutorialsEnabled(bEnable) end (resident/mrxguitutorial.lua:264-265). Setter counterpart to TutorialsEnabled; see Notes for modders below.
Callback
—
No call sites found in the decompiled corpus. Exists per live enumeration; unconfirmed.
ToStringL
—
No call sites found in the decompiled corpus. Exists per live enumeration; presumed a localized/long string conversion by naming, unconfirmed.
WriteToConsole
—
No call sites found in the decompiled corpus. Exists per live enumeration; presumed a debug-console print by naming, unconfirmed.
Notes for modders
StringToGuid/GuidToString bare-global aliasing. The same aliasing pattern already documented on Pg.GetGuidByName shows up here. Grepping the corpus finds StringToGuid called in two forms: the namespaced Sys.StringToGuid(...) (e.g. vz/wifpmcgarage.lua:243, vz/wiftutorialgatehonk.lua:10) and a bare, unqualified StringToGuid(...) used far more often across vz/chicon002.lua, vz/meccon001.lua, resident/mrxguihudvehicledisguise.lua, resident/mrxguiinterface.lua, resident/mrxsupportdesignatorsmoke.lua, resident/oilrig.lua, and others — always with the identical "0x..."-style hex-string argument shape. No GuidToString call site was found using a bare unqualified form (every observed call site uses Sys.GuidToString(...)), so the aliasing evidence is one-directional here — strong for StringToGuid, unconfirmed for GuidToString. As with Pg.GetGuidByName, this is the most plausible reading of consistent call-site behavior (a function aliased onto both _G and Sys), not something confirmed by reading engine source. Prior project notes on a bare-global StringToGuid discovery line up with this: it is very likely the same function as Sys.StringToGuid, just reachable at two scopes.
TutorialsEnabled/SetTutorialsEnabled gate the tutorial-hint HUD message system.Sys.TutorialsEnabled() is checked directly in resident/mrxtutorialmanager.lua (lines 98, 125, 181) before showing or updating a tutorial message, and both functions are read/written defensively (checked for existence with if Sys.TutorialsEnabled then ...) in resident/mrxguitutorial.lua and resident/mrxguipausescreen.lua (the options-menu toggle for this setting). This is exactly the gate behind the custom-HUD-message technique documented in Snippets: Show a custom HUD message — that snippet reuses the same generic tutorial-popup primitive MrxTutorialManager drives, and Sys.TutorialsEnabled() is the switch that must be true (or bypassed) for it to actually display. Don’t re-derive the HUD-message mechanics here; see that snippet and the MrxTutorialManager page for the full picture, this page only documents the two Sys entry points that gate it.
Several functions on this namespace (FinishedShell, AutoLoad, GetForceNewGame, IsDemoMode, IsFinalConfig, IsLoadingOrStreaming, StartWithResources, SetTutorialsEnabled, TutorialsEnabled, RequestAutosave) are consistently called guarded — if Sys.SomeFunction and Sys.SomeFunction() then — rather than called directly. That pattern across many otherwise-ordinary functions suggests these entry points may not exist on every build/platform/version of the engine, so defensive existence-checking before calling them is the safer approach for mod code too, even though live enumeration confirms they exist on at least this build.
The time-utility family (MainTimeStamp/RealTimeStamp + TimeStampMark + TimeStampGetElapsed) is a real, working elapsed-time-polling primitive independent of the callback-based Event.TimerRelative pattern documented on the Event page — use the Sys family when you need to check “how long has it been” on demand, and Event.TimerRelative when you want a callback to fire automatically after a delay.
Functions marked “no call sites found” are real (confirmed via the live pairs(Sys) dump) but their argument shape is a guess based on naming convention only — don’t build mods around them without testing in-game first.