The whitelist

For your safety

The whitelist is there to keep you safe. A part’s code can only use the namespaces and types on these lists, so it can’t reach your files, your network or anything else on your computer. That’s what lets you download parts from the Workshop with confidence.

CRUMB checks every line against the lists as you type and again when the part compiles. Anything else is refused with one of three errors, and a part that breaks the rules won’t load, whether it comes from a save file or the Workshop.

This page is generated from the code that compiles each half, so it always matches what CRUMB enforces. Circuit logic and Component logic explain how to work within it.

Namespaces

	Circuit logic	Component logic
Allowed	Simulation	Simulation, CRUMB.Script.Component.Logic, CRUMB.Script.Component.Logic.Wrappers
using lines	System, System.Collections.Generic	System, System.Collections.Generic, CRUMB.Script.Component.Logic.Wrappers

An allowed namespace includes every namespace inside it. CRUMB adds the using lines for you, and they only save typing: System is there so you can write Math, and opens nothing else in System.

Types

Outside those namespaces, both halves may use these types and nothing else:

void, bool, byte, sbyte, short, ushort, int, uint, long, ulong, char, float, double, decimal, string, object, IntPtr, UIntPtr, Nullable<T>, List<T> and Math.

Nullable<T> is what you write as double? or int?, and Math is System.Math.

How the check reads your code

• Types you declare yourself are always allowed: a struct that holds one sample, an enum of modes, a small helper class.
• Arrays and pointers are allowed when what they hold is: double[], int*.
• Every type argument counts: List<double> is allowed, and List<Random> isn’t.
• A member is checked through its type: Math.Sqrt is allowed, and MathF.Sqrt isn’t, because MathF isn’t on the list.
• var hides nothing: the type it stands for is checked.

Common things that aren’t on it: Dictionary, HashSet, tuples, Random, MathF, Func and Action, exception types, LINQ, files and the network.

Methods tied to one hook

Some methods only make sense at one moment in a step, so they can only be called inside one hook. Write the call in that hook itself: a call from a helper method of your own is refused, even when the hook calls the helper. A lambda or local function written inside the hook counts as the hook.

Method	Call it only inside	On
Fail	CheckFailure	BaseCircuitLogic

Errors

Error	Means	Message
CRUMB001	Method call restricted	The method ‘‹method›’ can only be called within: ‹hooks›
CRUMB002	Namespace restricted	The namespace ‘‹namespace›’ is not allowed in this script type. Allowed namespaces: ‹allowed namespaces›.
CRUMB003	Type restricted	The type ‘‹type›’ is not allowed in this script type. Allowed namespaces: ‹allowed namespaces›. Allowed types: ‹allowed types›.

Generated from the CRUMB source, commit fcec660d, 2026-10-29.