CC: Create Material Checklist Peripheral

A small NeoForge addon for Minecraft 1.21.1 that lets CC:Tweaked computers read Create Material Checklists from placed Create Clipboards.

The mod does not add new blocks, items, or GUIs. It adds Lua peripheral methods to Create's placed Clipboard block entity.

What it does

Create can print a Schematicannon Material Checklist onto a Clipboard. Normally, CC:Tweaked can only see the item name and an opaque NBT/data hash, not the checklist contents.

This addon reads Create's real Clipboard data component on the Java side and exposes the useful parts to Lua.

You can use it to:

• read all Clipboard pages and entries;
• read item rows from a printed Material Checklist;
• get a compact list of missing materials;
• use that list for storage systems, autocrafting, logistics, or dashboards.

Requirements

Target versions used by this project:

Dependency	Version
Minecraft	1.21.1
NeoForge	21.1.233
Create	6.0.10-280
CC:Tweaked	1.119.0
Java	21

Development setup

macOS

If you use the included justfile:

just install-tools-macos

If java -version still does not show Java 21, add Java 21 to your shell path:

export PATH="$(brew --prefix openjdk@21)/bin:$PATH"
export JAVA_HOME="$(/usr/libexec/java_home -v 21)"

Linux

Arch/Manjaro:

just install-tools-arch

Ubuntu/Debian:

just install-tools-ubuntu

Common commands

just setup        # make Gradle wrapper executable and print Gradle info
just deps         # download/refresh Gradle dependencies
just compile      # compile Java sources
just lint         # run Gradle checks
just build        # build the mod jar
just run-client   # run Minecraft client in the dev environment
just run-server   # run a dev server
just jar          # list built jar files

Equivalent Gradle commands:

./gradlew compileJava
./gradlew check
./gradlew build
./gradlew runClient

The built mod jar will be in:

build/libs/

How to test in game

1. Start the dev client:

   just run-client

2. Create a Material Checklist using Create's Schematicannon and a Create Clipboard.

3. Place the written Clipboard in the world.

4. Connect it to a CC:Tweaked computer using a wired modem, or place the computer/modem so the Clipboard is visible as a peripheral.

5. In Lua, inspect available peripherals:

   for _, name in ipairs(peripheral.getNames()) do
     print(name, peripheral.getType(name))
     print(textutils.serialize(peripheral.getMethods(name)))
   end

6. Wrap the Clipboard peripheral and read missing items:

   local cb = peripheral.wrap("right") -- replace with the real side or peripheral name
   
   print("Has content:", cb.hasClipboardContent())
   print("Type:", cb.getClipboardType())
   
   local missing = cb.getMissingItems()
   
   for _, item in ipairs(missing) do
     print(item.name .. " x" .. item.count)
   end

Lua API

The peripheral is attached to placed Create Clipboards.

hasClipboardContent()

Returns true when the Clipboard has Create Clipboard content.

local hasContent = cb.hasClipboardContent()

getClipboardType()

Returns the Create Clipboard type as a lowercase string, or "empty" if no content exists.

local type = cb.getClipboardType()

getPageCount()

Returns the number of pages on the Clipboard.

local pages = cb.getPageCount()

getPages()

Returns all Clipboard pages as nested Lua tables.

local pages = cb.getPages()
print(textutils.serialize(pages))

Shape:

{
  {
    {
      checked = false,
      text = "Stone x128",
      itemAmount = 128,
      item = {
        name = "minecraft:stone",
        displayName = "Stone",
        count = 1,
        maxCount = 64,
      },
    },
  },
}

getEntries()

Returns all entries from all pages in one flat list.

Each entry includes page and index.

local entries = cb.getEntries()

getItemEntries()

Returns only entries that have an item icon.

This includes completed rows too, but for completed Material Checklist rows, itemAmount may be 0 because Create stores the missing amount there.

local items = cb.getItemEntries()

getMissingItems()

Returns a compact grouped list of unfinished Material Checklist item rows.

local missing = cb.getMissingItems()

for _, item in ipairs(missing) do
  print(item.name, item.count)
end

Shape:

{
  {
    name = "minecraft:stone",
    displayName = "Stone",
    count = 128,
  },
  {
    name = "create:shaft",
    displayName = "Shaft",
    count = 32,
  },
}

Important limitations

It reads placed Create Clipboards, not inventory item stacks

This addon is designed for a Clipboard placed in the world as a block entity. It does not make normal CC:Tweaked inventory methods expose raw item data components.

It is best for missing materials

Create's printed Material Checklist stores unfinished rows with an item icon and a positive itemAmount. Completed rows are usually checked and may have itemAmount = 0.

So getMissingItems() is reliable for answering:

What materials are still missing?

It is not meant to reconstruct the original full required / gathered / missing state after the checklist has already been completed.

It does not parse CC:Tweaked's nbt hash

CC:Tweaked exposes only an opaque hash for item data in inventory APIs. This addon avoids that by reading Create's Clipboard data directly on the Java side.

Project structure

src/main/java/com/syrnnik/ccmcp/
  CCCreateMaterialChecklistPeripheral.java   # main mod class, registers the generic peripheral
  ClipboardChecklistPeripheral.java          # Lua API for placed Create Clipboards

src/main/templates/META-INF/neoforge.mods.toml
  Mod metadata and dependencies

src/main/resources/assets/ccmcp/lang/en_us.json
  English mod display name

build.gradle
  NeoForge, Create, and CC:Tweaked dependencies

gradle.properties
  Version constants and mod metadata

justfile
  Convenience commands for setup, build, run, and checks

Troubleshooting

java -version is not Java 21

Install Java 21 and set JAVA_HOME correctly.

On macOS with Homebrew:

export PATH="$(brew --prefix openjdk@21)/bin:$PATH"
export JAVA_HOME="$(/usr/libexec/java_home -v 21)"

The Clipboard does not appear in peripheral.getNames()

Check that:

• the Clipboard is placed in the world;
• it is connected through a CC:Tweaked wired modem or adjacent peripheral connection;
• the modem is activated;
• the mod is installed on both client and server in multiplayer;
• Create and CC:Tweaked versions match the target versions.

getMissingItems() returns an empty list

Possible reasons:

• the Clipboard is empty;
• the Clipboard is not a printed Material Checklist;
• all checklist rows are completed;
• the checklist stores visible text but no item icons.

Use this for debugging:

print(textutils.serialize(cb.getPages()))