Standard Library Modules

The standard library is a set of helpers that the compiler turns into commands and resource files. They are grouped into modules; import a module before calling its helpers:

from stdlib import event, text, score

The modules are text, score, score.objective, random, timer, storage, item_component, schedule, selector, position, bossbar, team, entity, math, event, datapack, and the experimental resource_pack. This page covers the command helpers. event is described in Events, datapack and item_component in Data Pack Resources, and resource_pack in Resource Packs.

Calling a helper from a module that isn’t imported fails with the missing-stdlib-module diagnostic:

Error: missing-stdlib-module: module 'text' not imported.
Add `from stdlib import text` or use `import stdlib` to enable all modules.
See https://deveworld.github.io/cobble/docs/stdlib/modules.html for the import and versioning model.

The [stdlib] version setting in cobble.toml controls this check. version = 2 is the default and requires the imports above. version = 1 keeps every module active as in 0.7.x and prints a deprecation warning once per build. Helper behavior and generated output are the same under both versions.

[stdlib]
version = 2

Text

from stdlib import text

def notify():
    text.tellraw("@a", {"text": "Loaded", "color": "green"})
    text.tellraw("@a", text.plain("Plain message"))
    text.tellraw("@a", text.colored("Gold message", "gold"))
    text.tellraw("@a", text.score("@s", "points"))
    text.tellraw("@a", text.selector("@p"))
    text.title("@a", "Ready")
    text.subtitle("@a", {"text": "Go", "bold": True})
    text.actionbar("@a", "Running")

text.plain, text.colored, text.score, and text.selector return JSON text components for use inside other helpers or JSON resource declarations. Colors accept Minecraft named colors or #RRGGBB.

Score

from stdlib import score, score.objective

def update_score():
    score.set("points", 10)
    score.add("points", 5)
    score.remove("points", 2)
    score.copy("backup", "points")
    score.operation("points", "+=", "backup")
    score.reset("backup")
    score.objective.add("points", "dummy", "Points")
    score.objective.display("sidebar", "points")

Score helpers use the pack’s variable objective, <namespace>.vars.

Random

from stdlib import random

def roll():
    random.int("roll", 1, 6)
    random.bool("coin")

Random helpers compile to Minecraft’s random value command and store the result in a scoreboard value. A single-value random.int("score", n, n) range is lowered to a direct scoreboard set because Minecraft rejects degenerate random value n..n ranges.

Timer

from stdlib import timer

def cooldown():
    timer.set("cooldown", 20)
    timer.tick("cooldown")
    timer.done("cooldown")   # writes cooldown_done as 0 or 1
    timer.reset("cooldown")

Storage

from stdlib import storage

def save_status():
    storage.set("status", {"ready": True, "count": 3})
    storage.merge("status", {"extra": "ok"})
    storage.copy("status_copy", "status")
    storage.set(storage.path("players", "current"), "alex")
    storage.append("events", "loaded")
    storage.get(storage.index("events", 0))
    storage.read_score("event_count", "events")
    storage.read_score("ready_flag", "status.ready", 10)
    storage.remove("status.extra")

Storage helpers write to <namespace>:global. storage.read_score(score, path) stores what data get returns: a number (floored), or the size of a list or compound, or the length of a string. With the optional third scale argument, the value at path must be a number. storage.path(), storage.child(), and storage.index() return storage path strings for use inside storage helpers; they do not emit commands when used by themselves.

Schedule, Bossbar, Team, Entity, Selector, And Position

from stdlib import schedule, bossbar, team, entity, selector, position

def setup_ui():
    schedule.once("tick", "20t", "replace")
    schedule.clear("tick")
    bossbar.add("timer", "Timer")
    bossbar.set_max("timer", 100)
    bossbar.set_players("timer", "@a")
    team.add("runners", "Runners")
    team.modify("runners", "color", "green")
    entity.tag_add("@a", "runner")
    entity.effect_give("@a", "minecraft:speed", 10, 1, True)
    entity.teleport(selector.current(), position.relative(0, 1, 0))

selector.* and position.* return plain selector or coordinate strings for use inside other helpers and emit no commands when used by themselves. These helpers are thin wrappers over Minecraft commands, so use raw commands when a specialized option is not covered yet.

Math

from stdlib import math

def calculate():
    root = math.sqrt(100)
    magnitude = math.abs(-50)
    low = math.min(10, 20)
    high = math.max(10, 20)

math.sqrt uses a generated scoreboard helper.