Command System

Command annotations

SSEC command registration is built around five annotations:

• @SSCommand declares a root command or subcommand class
• @SSCExecute marks the executable method
• @SSCArgument maps method parameters to Brigadier arguments
• @SSCAlias registers redirect aliases
• @SSCPermission applies permission rules

Shape of a command

@SSCommand("greeting")
@SSCAlias({ "hi", "hello" })
@SSCPermission(permission = PermissionLevel.GAME_MASTER)
public class GreetingCommand {

    @SSCExecute
    public static void execute(
            CommandContext<CommandSourceStack> ctx,
            @SSCArgument("name") String name
    ) {
        // ...
    }

    @SSCommand(value = "shout", parent = GreetingCommand.class)
    public static class ShoutCommand {
        @SSCExecute
        public static void execute(
                CommandContext<CommandSourceStack> ctx,
                @SSCArgument("msg") String msg
        ) {
            // ...
        }
    }
}

This produces a root command plus a nested subcommand without hand-writing literal and argument builders.

What CommandRegistrar does

The registrar:

• verifies @SSCommand is present
• builds a Brigadier tree from the annotated class graph
• resolves parent-child relationships, including cross-file parents
• registers root aliases and subcommand aliases
• applies permission predicates
• maps Java parameter types to Brigadier argument types through the adapter registry

Built-in argument adapters

CommandRegistrar pre-registers adapters for primitives, strings, vectors, entities, block positions, NBT, scoreboard types, colors, styles, UUIDs, and more.

For the full supported set, see Argument Types.

Custom argument types

If a parameter type is not built in, register an SSCArgumentAdapter during onInitializeSSEC().

public class MyCommandInitializer implements SSECInitializer {
    @Override
    public void onInitializeSSEC() {
        CommandRegistrar.registerAdapter(MyType.class, new MyTypeAdapter());
    }

    @Override
    public String[] getPackagesToScan() {
        return new String[] { "com.example.mymod.command" };
    }
}

Practical rules

• Keep @SSCExecute methods static unless you have a reason to instantiate a target.
• Put reusable permission policy on the command class, then use propagate when children should inherit it.
• Register custom adapters before the scan runs.
• Treat aliases as redirects, not independent command implementations.