Variables

Everything a processor knows without asking: constants, time, map size. The list and the descriptions come from the game itself (v160.4).

Processor variables

The in-game window does not list them: they live in the processor, not in the global list.

@counter	The number of the instruction that will run next. The only built-in variable that can be changed: writing to it is a jump, and set @counter 0 starts the program over.
@unit	The unit taken by the last ubind. It is the one ucontrol and uradar are addressed to.
@queries	The list query puts what it found into. Only a world processor has it.world processor only

Processor

@this	The logic block executing the code
@thisx	X coordinate of block executing the code
@thisy	Y coordinate of block executing the code
@links	Total number of blocks linked to this processors
@ipt	Execution speed of the processor in instructions per tick (60 ticks = 1 second)

General

false	0
true	1
@pi	The mathematical constant pi (3.141...)
@e	The mathematical constant e (2.718...)
@degToRad	Multiply by this number to convert degrees to radians
@radToDeg	Multiply by this number to convert radians to degrees

Map

@time	Playtime of current save, in milliseconds
@tick	Playtime of current save, in ticks (1 second = 60 ticks)
@second	Playtime of current save, in seconds
@minute	Playtime of current save, in minutes
@waveNumber	Current wave number, if waves are enabled
@waveTime	Countdown timer for waves, in seconds
@mapw	Map width in tiles
@maph	Map height in tiles

Network/Clientside [World Processor Only]

@server	True if the code is running on a server or in singleplayer, false otherwise
@client	True if the code is running on a client connected to a server
@clientLocale	Locale of the client running the code. For example: en_US
@clientUnit	Unit of client running the code
@clientName	Player name of client running the code
@clientTeam	Team ID of client running the code
@clientMobile	True if the client running the code is on mobile, false otherwise
@clientMusicPlaying	True if any music is currently playing
@clientCurrentMusic	Name of the current track being played, or null

Lookup

@blockCount	Total number of types of block content in the game; used with the lookup instruction
@unitCount	Total number of types of unit content in the game; used with the lookup instruction
@itemCount	Total number of types of item content in the game; used with the lookup instruction
@liquidCount	Total number of types of liquid content in the game; used with the lookup instruction
@wait	The game gives no description.
@ctrlProcessor	The game gives no description.
@ctrlPlayer	The game gives no description.
@ctrlCommand	The game gives no description.

Data taken from Mindustry v160.4 by the project generators.