1. Your first command

Create config/ignis/mycommands.lua and run /ignis reload after each change to see your commands in-game.

1. Simplest command

register("ping", function(ctx)
    ctx.player:sendMessage("Pong!")
end)

The handler receives a ctx table with ctx.player. Call methods on it to interact with the player.

2. Arguments

Add a <target:player> argument — the value arrives as a positional parameter:

register("heal <target:player>", function(ctx, target)
    target:heal(20)
    ctx.player:sendMessage("Healed " .. target.name)
end)

Wrap an argument in [...] to make it optional. Missing optional args are nil:

register("heal [<target:player>]", function(ctx, target)
    local t = target or ctx.player
    t:heal(20)
end)

See Registering Commands for all argument types.

3. Choice arguments

A choice argument limits input to predefined options and provides tab completions:

register("gamemode <mode:choice=survival,creative,adventure,spectator> [<target:player>]", function(ctx, mode, target)
    local t = target or ctx.player
    t:sendMessage("Set " .. t.name .. " to " .. mode)
end)

4. Timers with mc.schedule

Schedule a one-shot action with a delay in ticks (20 ticks = 1 second):

register("callback", function(ctx)
    ctx.player:sendMessage("You'll be healed in 5 seconds...")
    mc.schedule(100, function()
        ctx.player:heal(20)
        ctx.player:sendMessage("Healed!")
    end)
end)

Repeating timers with mc.scheduleRepeating(delay, interval, callback):

register("countdown <seconds:int>", function(ctx, seconds)
    local remaining = seconds
    local id -- declare first so the callback can see it
    id = mc.scheduleRepeating(0, 20, function()
        remaining = remaining - 1
        if remaining <= 0 then
            mc.broadcast("Go!")
            mc.cancelTask(id)
        else
            mc.broadcast(remaining .. "...")
        end
    end)
end)

See the mc.* API for scheduler options.

5. Coroutine delays with mc.sleep

Command handlers and mc.schedule callbacks support mc.sleep directly.

mc.sleep(ticks) pauses execution for the given number of ticks. See Async API for details:

register("delayedheal", function(ctx)
    ctx.player:sendMessage("Healing in 3...")
    mc.sleep(20)
    ctx.player:sendMessage("2...")
    mc.sleep(20)
    ctx.player:sendMessage("1...")
    mc.sleep(20)
    ctx.player:heal(20)
    ctx.player:sendMessage("Healed!")
end)

6. Async HTTP with mc.fetch

mc.fetch(url) sends an HTTP GET request and waits for the response. See Async API for POST config and response fields:

register("playerinfo", function(ctx)
    local res = mc.fetch("https://api.github.com/users/" .. ctx.player.name)
    if res.ok then
        local data = res.json
        ctx.player:sendMessage("GitHub account: " .. (data.login or "not found"))
    else
        ctx.player:sendMessage("API error: " .. (res.error or res.status))
    end
end)

7. Permissions

Pass a permission node as the third argument to register. Players without it can’t use the command:

register("kick <target:player> [<reason:text>]", function(ctx, target, reason)
    target:kick(reason or "Kicked by an operator")
end, "admin.kick")

8. Effects for flair

See World API and Vector API for particle, sound, and vec options:

register("fart", function(ctx)
    local p = ctx.player
    local pos = p.pos
    p.world:playSound("minecraft:entity.player.burp", pos, 1.0, 1.0)
    p.world:particle("minecraft:heart", vec(pos.x, pos.y + 1, pos.z), {
        count = 5,
        delta = { 0.5, 0.5, 0.5 }
    })
    p:sendMessage("You farted!")
end)

Next steps

• Events and storage — part 2 of this guide: reacting to events and saving data
• Events — react to player joins, block breaks, chat, and more
• Async API — detailed mc.fetch and mc.sleep reference
• Storage — persist data across reloads with mc.data and player.data
• Libraries — formatting templates, simple registrations, chest GUIs
• Language extensions — \{ ... } lambda syntax