Command Tasks

Command registration, execution, and Tab completion.

---

command.register

Registers a command.

• Request:

{
  "pluginName": "<name>",
  "commandName": "<name>",
  "callbackId": "<cbId>",
  "completerCbId": "<cbId>",
  "description": "<text>",
  "usage": "<text>",
  "permission": { "node": "<节点>", "default": "all | op | none" },
  "aliases": ["<alias1>", "<alias2>"]
}

Field	Required	Description
pluginName	Yes	Owning plugin name
commandName	Yes	Command name (without /)
callbackId	Yes	Command execution callback ID (persistent: true)
completerCbId	No	Tab completion callback ID (persistent: true)
description	No	Command description
usage	No	Usage hint (e.g. "/cmd <arg1> <arg2>")
permission	No	Permission node object { "node", "default" } (default: "all" all players have by default / "op" ops by default / "none"; wrapping a string into an object is done on the JS side, Java does no compatible conversion). The node is registered into the Paper permission system (manageable by permission plugins); checked at execution time: the permission check (onPermissionCheck) takes priority, falling back to hasPermission when unhandled
aliases	No	Alias list

• Return: boolean

When a player (or the console) executes the command, the runtime delivers data to callbackId through the cb channel:

{
  "sender": { "name": "<name>", "uuid": "<uuid>", "isPlayer": true },
  "args": ["<arg1>", "<arg2>"],
  "label": "<commandName>"
}

• args: the array of command arguments typed by the player
• label: the command name actually used (may be an alias)
• isPlayer: false indicates console execution, in which case uuid is empty

JS-side sender conversion (yeow-api): isPlayer: true → a real Player object (with all methods such as asynchronous sendMessage); otherwise → the string 'CONSOLE'. Executor check: p.sender === 'CONSOLE'.

The executor may be an async function and use await internally to call asynchronous APIs.

command.dispatch

Executes a command as the console.

• Request: { "command": "<cmd>" }
• Return: boolean

Behavior is equivalent to calling dispatchCommand or Bukkit.dispatchCommand(Bukkit.getConsoleSender(), cmd).

command.unregisterAll

Unregisters all commands of the specified plugin.

• Request: { "pluginName": "<name>" }
• Return: true

Usually called before a plugin hot-reload to ensure that the old code's commands are removed correctly.

---

Tab Completion

Triggering Completion

When completerCbId was passed at command.register time, and the player presses the Tab key, the runtime delivers a completion request to that ID through the cb channel:

{
  "sender": { "name": "<name>", "uuid": "<uuid>", "isPlayer": true },
  "args": ["<typed arg1>", "<typing arg2>"],
  "_reqId": "<tab:cmd#N>"
}

• The last element of args is the argument currently being typed (may be an empty string)
• _reqId is the unique id of this completion request (the same technique as the event's _eventId) — it must be returned verbatim in command.tabComplete. Do not substitute completerCbId: it is a persistent, one-per-command id, so concurrent requests (two players pressing Tab at the same time) cannot be told apart and would overwrite each other's wait slot
• The completer must return results through the command.tabComplete task

command.tabComplete

The completion response task.

• Request:

{
  "type": "command.tabComplete",
  "params": {
    "callbackId": "<_reqId>",
    "completions": ["<suggestion1>", "<suggestion2>"]
  }
}

callbackId must be the _reqId carried by the completion request (returned verbatim).

• Return: produces no return value (true)

Asynchronous Completion

The completer can be an async function. If it returns a Promise, the completion is automatically submitted as an empty completion list at the first await (equivalent to complete([])); the asynchronous logic continues in the background but has no effect on the current Tab completion.

Manual Completion Mode

If the application code needs to fetch data asynchronously before completing, it can choose not to return a completion list immediately, and instead call command.tabComplete on its own to submit the result after the asynchronous operation finishes.