# Registering Feature Commands

This guide shows how to expose commands from a feature using the OMS command system.

The example extends `HelloWorldFeature` with a simple command that prints a message to the console.

***

### Overview

Features can expose commands by overriding `additionalCommands`.

These commands are automatically registered under:

```
/oms feature <feature_id> ...
```

***

### 1. Create a command entry

Commands are defined by extending `OMSCommandEntry`.

```kotlin
class HelloWorldPrintCommand(
    private val feature: HelloWorldFeature
) : OMSCommandEntry() {

    override fun init(): ArgumentBuilder<CommandSourceStack, *> {
        return Commands.literal("print")
            .executes { ctx ->
                val source = ctx.source
                val server = source.server
                server.playerList.broadcastSystemMessage(
                    Component.literal(
                        feature.config.message()
                    ),
                    false
                )
                1
            }
    }
}
```

This defines:

* command name: `print`
* execution logic: print message from config

***

### 2. Attach command to the feature

Override `additionalCommands` in your feature:

```kotlin
class HelloWorldFeature(
    configProvider: ConfigProvider<CHelloWorldFeature>
) : OmsFeature<CHelloWorldFeature>(configProvider) {

    override val additionalCommands = listOf(
        HelloWorldPrintCommand(this)
    )
    
}
```

***

### 3. Use the command

After startup, the command will be available under:

```
/oms feature hello_world print
```

***

### Notes

* Commands are defined using Brigadier
* Features expose commands via `additionalCommands`
* Command structure is hierarchical
* Commands are registered automatically by OMS


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