Core Rules

Core Rules is a complete Linux, Windows 11 and macOS version of AD&D Core Rules 2.0 and its Expansion (TSR/Evermore, 1998-1999), the character manager and Dungeon Master's toolkit for Advanced Dungeons & Dragons 2nd Edition. It is written in Rust and runs natively: with GTK 4 and libadwaita on Linux, with no Wine, with WinUI 3 on Windows 11 and with SwiftUI on the Mac. On Linux it comes as a .deb for Ubuntu, an .rpm for Fedora, a pacman package for Arch Linux (and CachyOS and Omarchy), a Flatpak and an AppImage; on Windows 11 it comes from the Microsoft Store, and on Apple Silicon Macs as a .dmg. All three are final releases. See Installing.

Every screen of the original program is here: the Character Generator with Create, Enter and Update Character, kits and Player's Option, the character sheet, parties, the NPC, treasure and encounter generators, Table Rolls, editors for every user database, DM Toolkit packages, the rule books and the help. The app reads and writes the original's own data files, so characters, monsters, encounters and packages made in either program open in the other.

Version 1.2.0, on Linux, Windows 11 and macOS. New in 1.2.0: Import Add-ons… brings in every add-on in a folder at once, and the Community Add-ons Collection comes as one .zip for it, on all three systems. Every feature was checked against the original programs and went through a full round of manual tests. Players and Dungeon Masters ran 1.0 on Fedora 45 beta, Ubuntu 26.10, Bazzite, Arch Linux and CachyOS, and the Windows 11 and macOS versions each went through a beta, where they worked as they should. Download it for your distribution or your Mac, get it from the Microsoft Store, or visit the website.

On Windows 11

The Windows 11 version has every screen of the Linux one, over the same backend and the same data files, with the look of a Windows 11 app: the navigation pane, command bars, settings cards, the system's light, dark and high-contrast themes and the Mica backdrop. The help files of the discs open in the app's own Help page, since Windows 11 no longer has a WinHelp reader.

On macOS

The macOS version has every screen of the other two, over the same backend and the same data files. It is a native Mac app in SwiftUI: the sections, the entries and the details in three columns, every action in the menu bar, Settings, and the sheets, the help, the books and the generators in their own windows. It runs on Apple Silicon Macs with macOS 14 or newer (installing). These pictures show it in Portuguese.

You need the original discs

This project contains no TSR or Wizards of the Coast content. The rules, books, monsters, pictures and help all come from a copy of AD&D Core Rules 2.0 (and, for everything the app creates and edits, the Expansion) that you already own. The app copies what it needs from the CD, its ISO image or an installation once, and then works without them (see Getting the rules data).

If your discs are lost, scratched or unreadable, disc images have been preserved by the Internet Archive:

• AD&D Core Rules 2.0 (1998)
• AD&D Core Rules 2.0 Expansion (1999)

Copyright notice. AD&D Core Rules and its contents are copyrighted by Wizards of the Coast, and these images are not covered by this project's license. Download an image only if you own the original disc it replaces, and keep the data the app extracts for your own use; do not redistribute it. This project does not host these files and is not responsible for them. The links above are the archive's item pages, where you can read about each item before choosing whether to download it.

Status and roadmap

1. Release candidates (done). 1.0.0-rc1 and 1.0.0-rc2 went to real users, and the problems they found were fixed.
2. 1.0 (done). The release candidate was confirmed stable on Fedora 45 beta, Ubuntu 26.10, Bazzite, Arch Linux and CachyOS, and became 1.0.0: a faithful replacement for the original program.
3. Windows 11 (done). A Windows 11 version in this repository, with a native WinUI 3 interface written in Rust over the same backend, distributed through the Microsoft Store. Every screen is ported; after a beta on the Store it was released as 1.0.1, the same version as Linux. From now on every feature ships on Linux and Windows together.
4. macOS (done). A native SwiftUI version for Apple Silicon Macs, in this repository over the same backend, distributed as a .dmg. After a beta it was released as 1.1.0 on the three systems, and from now on every feature ships on all three together.
5. New features (in progress). From then on the app improves on the original and moves away from it, step by step, until it no longer needs the original program's files to work. 1.2.0 brings the first: Import Add-ons… and the Community Add-ons Collection as a .zip.

The roadmap has the plan, what is done and what each step needs; the decision log records every decision that shaped the app's scope and behavior.

Features

Everything the app saves opens in the original programs. Where a feature says it works as the original does, its results were compared with files the original programs wrote.

Library

• Browse the characters, races, classes, items, spells, psionic powers and monsters of an installation, of its CD, or of a data package
• Extract Data from CD… copies what the app uses from the Core Rules 2.0 or Expansion CD (its ISO image or the mounted CD) or an installation into the app's data folder, so neither the CD nor Wine is needed again
• Weapons, armor, equipment and magical items show their icons, those of Bitmaps/Equip or the user's own in UserBMP, on their pages and in a character's equipment
• The Core Rules books in a reader with contents and search
• Lists sort exactly as Windows sorts them (CompareStringW, checked under Wine)

Character Generator

• New Character (Ctrl+N), following the original wizard: campaign setting, ability rolls (Methods I to VI, entered scores or Player's Choice), race and subrace (with the original's question for the point a race such as the Mongrelman adds to an ability of the player's choice), class, details (with a name from the NPC generator for the subrace, given when the character has none and again from the button beside the name, and the Background… dialog's event, with Select Randomly, and history), proficiencies and languages, rogue skill points, psionics for a psionicist (disciplines, powers and modes, with the 1st-level PSPs rolled), spells (each learned as the original learns it: the chance to learn rolled, and a question before passing over a limit of level, Intelligence, spells per level or barred school), wild talents for a character who is not a psionicist (with the Expansion: Test for Wild Talents, and one roll on Table 83 for a wild talent) and starting equipment. The original has no campaign settings, so each setting only narrows what the installed databases offer, following its campaign book. Once the rules are chosen, the Expansion's "Core Rules Vs Player's Option" message says which kind of character is being made, until "Do not show this window again" is ticked; Preferences turns it back on, as the original's User Options do
• Enter Character, the same wizard for a character that already exists on paper, as the original's Enter Character button: scores typed in from 1 to 25 and kept as typed, exceptional Strength at 18 whatever the class, any race and its classes with no minimums, All Classes… for any other combination (one class of each group), a free alignment and gender, and on the details page each class's level or experience in the Levels dialog (prime requisite bonus, level limits, character points per level), rolling hit points and PSPs for each level gained, with hit point and PSP arrows in place of the rolls. The later pages take what the sheet has: racial and class abilities, proficiencies, rogue points and spells of any level with no limits or totals checked, wild talents rolled as often as wanted or chosen from the list, the kit's equipment not imposed
• Kits in New Character, as the Expansion offers them: only those the character's scores, gender, alignment and classes allow, with the original's warnings and the kit's information text. The kit's fixed rogue skill adjustments, barred class abilities, schools, spells and languages are applied when the character is written, and again when an edit is saved. The kit's own rogue skill points, its bonus to one skill of a list, the skills it has the character choose and its list for the starting points (with the original's warning) are on the Rogue Skills page. The schools the kit bars are warned about on the Spells page and go unless ignored, and a kit limited to five schools has the wizard eliminate the rest, the spells offered following the schools kept. The kit's hit points go on every hit die roll and its own dice and percentages on the starting money. The Equipment page shows the kit's text, the items and the chosen weapon it requires, charges the kit's percentage of each price, gives the kit's free equipment, weapons and magic items, and warns when more money is kept than the kit allows
• Items a character may not use: buying one on the Equipment page of New Character or of an edit asks first, with the original's message about the class, race, class abilities or kit
• Class and kit proficiencies in New Character: the required ones go in first, bonus, free and kit-recommended ones cost less or nothing, the bonus, free, +1 and +2 picks are offered as the Expansion offers them, the kit's own starting slots are asked about, and a proficiency the kit bars brings the original's warning
• Kit weapon proficiencies in New Character: the kit's slots, prices and weapon list, the original's warnings for the weapons it bars or requires (its sword list, thrown weapons, every other one from a list), the nonweapon slots it lets weapons use, its requirements, the weapon to focus in, and Core Rules weapon specialization (2 slots for a bow, 1 for the others, a free one some kits give) with the original's questions; weapons out of class ask first (Core Rules) or cost more (Player's Option), as do a cleric's edged weapons and the class abilities that limit weapons, and unarmed combat goes to the classes and kits that allow it, never together with a weapon specialization
• Player's Option (Skills & Powers) creation, as the Expansion's Player's Option button: Methods VII to X, racial and class abilities bought with character points, subabilities, traits and disadvantages, proficiencies with ranks, broad and tight weapon groups (warriors and priests, 6 and 4 points, covering their weapons for the kit's checks, the specializations and the attack penalty), weapon of choice, expertise and specialization, unarmed combat, shield and armor proficiencies, fighting styles
• Portraits, in New Character and when editing: one of the race's portraits or any other in Bitmaps/Portrait, or a BMP, JPEG, GIF or PNG picture of your own, which the app cuts to the portraits' size and saves there as an 8-bit bitmap in the original's palette, so the original shows it too
• Editing a character: name, player, gender, alignment, kit (which rolls the social class again, as Update Character does), social class, background event (with Select Randomly, which picks one of the 20 events) and history, portrait, age, height, weight, hit points (moving the rolls as the original's arrows do), ability scores, subrace, racial and class abilities, schools and spheres, weapon proficiencies, weapon groups, weapon of choice, expertise, specializations, mastery, unarmed combat, shields, armor, fighting styles, traits and disadvantages (charging and refunding character points as Update Character does, with its questions and the kit's weapon warnings, the Core Rules slots left, the kit's free weapons at their levels, the kit's focus weapon, and the Cavalier's sword at 3rd level and horseman's weapon at 5th), rogue skill points at the current level (with the kit's own points, its bonus of each level and the skills it has the character choose, none of them spent), psionic disciplines and powers, wild talents (with the original's Test for Wild Talents, its risks and saving throws, and Roll for Wild Talents on Table 83) and psionic attack and defense modes (with Update Character's limits), nonweapon proficiencies (ranks, costs as New Character charges them, the kit's free ones at their levels, the Core Rules slots left, and the kit's warnings and questions), languages, spells known (learned with New Character's roll and questions), spellbooks and memorized spells (with the kit's barred schools, the schools beyond five to eliminate, the spheres to keep, its free sphere and its warning for a kit that never uses spells, as Update Character's Spells and Memorize pages ask, and the kit's notes on the schools and spheres of the Abilities page), the nine equipment groups with quantities (with the kit's text, and the original's question about an item the character may not use), and Spending Money, with the original's Buy and Sell mode: an item added is paid for with the spending money at the kit's percentage of its price (or refused with the original's messages), and one removed or lessened gives its price back
• Experience and levels per class, all classes or split, with the prime requisite bonus, hit point rolls, PSPs, character points and the Expansion's racial level limits, and the kit's own experience per level, cap on the bonus and hit points per level; the original's Levels dialog (each class's level from 1 to 100, which puts its experience at what the level takes, and the unspent character points to adjust), and hit point and PSP arrows; dual-classing for humans
• Character sheet: every section the originals export, shown in the app, printed, saved as PDF, or exported as the originals' TXT and HTML, matching their exports line for line, or as Markdown (in place of the Expansion's RTF); in the Expansion, the sheet's options choose its sections, their order and page breaks, and the printed border
• Parties: Manage Parties… puts characters in a party, takes them out or deletes every member; a character can be deleted, with Undo; the list filters by party; in the Expansion, Group Encounter… makes an encounter of a party's NPCs, or prints them as one in the original's full or condensed format
• Rebuild the character list: when Chars/index.chr cannot be read, or lists a character whose file is missing or damaged, the app offers to rebuild it from the character files, as the original does
• Convert to NPC and Convert to Character move a character to the DM Toolkit's NPCs and back, writing the same files as the Expansion

DM Toolkit

• NPC generator (New NPC, New NPC Group): Core Rules and Player's Option NPCs with kits, proficiencies, equipment, spells, psionics and rogue skills; New NPC Group lists the standard races, the kits and the alignments the line allows, as the original's Standard and Allowed choices (All Races, All Kits and Any Alignment list every one); with the same seed it saves the same NPCs as the Expansion
• Treasure generator: treasure types A to Z, table rolls, intelligent weapons, spell scrolls, Calculate and saved bundles (opened again or copied into a new one); with the same seed it saves the same bundles as both originals, byte for byte
• Encounter generator: encounters from templates with the originals' dice, dependents, items and treasure, the Encounter dialog's editing and totals (each monster's hit points set by hand or rolled again with Re-roll, New Monster from Add Monster, and View NPC and Print NPC on its NPCs' sheets), saved encounters (edited or copied into a new one) and the 2-20 tables (each roll's template picked from those of one frequency that pass the table's filter, opening on the roll's own frequency as the original does); View and Print on monsters, encounters, templates, 2-20 tables, saved treasure and treasure tables, each as the original's page; monster types, monsters, templates and encounters show the type's picture with Next Image (the original's Alternate Image(s)) and Full Screen, which shows it to the players in the original's frame
• Table Rolls on every table of the books, with the originals' dice and follow-up rolls
• Editors for every user database: races, classes (with the free spells, NWPs and class abilities each level grants, and Auto Fill from another class; changing a class's group, after asking, or deleting it takes it out of every race's combinations) and allowed combinations, parts (weapons, armor, kits and proficiencies, whose lists have the original's Magic Only, plus the ten other types in Other Parts: racial and class abilities, languages, schools, spheres, traits, disadvantages, gems and art, currency and Count), spells (with Schools…, which changes only a spell's schools and spheres, a standard spell's included, as the original's does), psionic powers, monsters (with their spells, their inventory in the Treasure Bundle Editor, their attacks, each made or changed in the Monster Attack editor the original has but hides, and Suggest XP Value), monster types, traps, treasure tables (each entry with its number found, chance of being intelligent, random contents from two tables, what it always contains and, for a scroll, its spells) and encounter templates (monsters, NPCs, items with their coins and escorts, traps, treasure types and the 2-20 table, with the original's dependents and "and"/"or" second groups). A monster type's picture is chosen among those in Bitmaps/Monsters and UserBMP, a race's among the portraits, or made from a picture of your own as portraits are (monster pictures go to UserBMP, at 300×300). A weapon's, piece of equipment's, magical item's, gem's or coin's picture, on General Info, is one of the icons of Bitmaps/Equip, found by the items that have it, one of yours in UserBMP, or made from a picture of your own (64×64, in UserBMP)
• Packages: Export, Import, New Package and Edit Package for .xpx packages with characters and any user record, byte for byte as the Expansion writes them; Core Rules 2.0 .xpt packages are imported and converted. Monsters travel in these packages (there is no .mon file). An imported part named like a standard one gets a "*", and Name Conflict asks for another name when a part has that one too; as in the Expansion, opening the folder renames the kits, nonweapon proficiencies, schools and magical items of yours that a standard one's name hides
• Import Add-ons… imports every add-on in a folder at once: the folder, its subfolders and its ZIP archives (also ZIPs inside ZIPs) are read, each .xpx and .xpt package is told apart by what it holds, and the list shows what comes in, what was found twice and what cannot be imported before anything is written. It backs up the user databases and characters first, imports from the oldest file to the newest, leaves out the characters already in the list, copies the add-ons' pictures where their records look for them and writes a log (see Community add-ons)

Core Rules 2.0 and the Expansion

Everything new follows the Expansion (AD&D Core Rules 2.0 Expansion). A Core Rules 2.0 installation without the Expansion opens read-only: Import Core Rules 2.0… (or cr import EXPANSION_DIR CORE_RULES_2.0_DIR) copies its characters and records into an Expansion installation, converted the way the Expansion converts a 2.0 package, and leaves the 2.0 folder untouched.

Everywhere

• Interface in English (US), Português (Brasil), Español, Italiano, Français and Deutsch (see Languages)
• Runs without Wine from a data package (see Getting the rules data)
• The cr command does the same from a terminal: cr chars, cr sheet, cr npc, cr treasure, cr encounter, cr table, cr userdb, cr export, cr import, cr package, cr party, cr delete, cr survey
• Help: the Help button and F1 on every screen open its topic of the program help, as the original's Help… buttons do; a right-click on a control shows its help, and on a race, class, item, spell, psionic power or monster its topic in the book's help (or, for a record of the user database, its description), and on a character, trap, encounter, template or saved treasure its summary, as the original does; the help window and the monster page can print; the Help menu has the Online Manual, the Tome of Help (every installed book's help) and About, with the original's version, copyright and credits. The installation's WinHelp files are read by the app's own help window
• Every file the app reads or writes is specified in docs/formats

Differences from the original

The app aims to do what the original does, the way it does it, and saves nothing the original cannot read. This is the complete list of where it differs, each one on purpose; the decision log says when and why each was decided.

Platform and setup

• Linux and Windows 11, no Wine. The app is a native GTK 4 program on Linux and a native WinUI 3 program on Windows 11, over the same backend. Windows 10 and older versions are not supported.
• No installation of the original needed. Extract Data from CD… copies what the app uses from the CD, its ISO image (read directly, with no mounting) or an existing installation into a local data folder. The original has to be installed from its CD.
• Core Rules 2.0 without the Expansion opens read-only. Everything new follows the Expansion. A 2.0 installation's characters and records are brought into an Expansion installation with Import Core Rules 2.0…, converted the way the Expansion converts a 2.0 package.
• Six interface languages. The original is in English only; the app's interface is also in Português (Brasil), Español, Italiano, Français and Deutsch. Rules texts from the original files stay in English.
• Preferences in place of User Options. The only User Options setting within scope, turning the "Core Rules Vs Player's Option" message back on, is in Preferences, together with the interface language.
• Its own help window. The original's WinHelp files are read and shown by the app, since Linux has no WinHelp.
• Campaign settings in New Character. The original has none. Choosing Forgotten Realms, Greyhawk, Dragonlance and the others only narrows the races and classes the installed databases offer, following each setting's campaign book; Generic offers everything, as the original does.
• A cr command-line tool does most of what the app does from a terminal. The original has nothing like it.

Features added

• Character sheet as PDF and Markdown. Besides printing and the original's TXT and HTML exports (identical line for line), the sheet can be saved as PDF, and exported as Markdown in place of the Expansion's RTF.
• The Monster Attack editor. The original has this editor but hides its New and Edit buttons, so monster attacks can only arrive by import; the app offers it.
• Packages made with the patched Expansion import. The CD's TSRP3.EXE rejects packages written by the later patched Expansion (many community add-ons were); the app reads both.
• Large packages import in the background, and the Import dialog folds a category of more than 200 items into one row.
• Import Add-ons… brings in every add-on in a folder, its subfolders and its ZIP archives at once, with their pictures; the original imports one package at a time.
• The Core Rules Community Add-ons Collection (see Community add-ons), 672 community add-ons converted to the Expansion's format, as one .zip for Import Add-ons….

Behavior that differs

• Re-roll keeps hand-set hit points. In an encounter, Re-roll rolls only the monsters whose hit points were not set by hand, as the original's later patch does (the unpatched program rolls them all). The encounter file has no place for that mark, so it holds while the encounter is open.
• Rebuilding the character list leaves out a character file that cannot be read, and says which one, where the original lists it as an empty character.
• Schools… on a standard spell writes Spells.dat when the spell is saved, keeping the previous file as Spells.dat.bak; the original writes it only from its internal Save Options screen.
• The NPC generator finishes an NPC whose kit names an item missing from the database, or who has no priest spells to choose from, and says what was left out, where the original stops with an error.
• Table Rolls lines its columns up; the text is the same as the original's.
• The first Table Roll after the app starts begins from the value the original has under Wine (44), where the original's comes from Windows memory.
• Where the original hangs, the app stops: a table that rolls again while the result is within 1 of the previous one gives up after 1,000 tries, and the hit point arrows skip a roll that could never be lowered.
• Character points and slots never go below 0 in Update Character; the original lets them, after asking.
• The database editors save only the file that changed, each time a record is saved, where the original writes every user file when its menu closes; the bytes are the same. A record imported under a standard record's name can still be edited while it keeps that name.

Not included

• Map Maker II, the Campaign Mapper and the dice roller. Campaign Mapper drawings inside a package are kept but not offered or imported.
• Core Rules 1.0 files.
• The original's animations and sounds (including the animated assistant of the Help menu) and its links to TSR's update and web pages.
• Analyze and Repair Database and Delete User Data: the original deletes its own Database menu when it starts, so no user reaches them there either.
• Sell and Buy Character Points on the Equipment page, which the original always hides.

Same as the original, although it may surprise

These were reported in testing and kept, because the original does the same:

• Roll Again in Table Rolls replaces the previous result instead of adding to it; only the follow-up rolls of one roll are listed together.
• A new Proficiency starts with MAC Bonus turned on.
• Move Into in a treasure bundle offers any item.
• View NPC and Print NPC in an encounter print the standard sections, whatever sheet options the character has.

Packages

• Packages target Ubuntu 26.04, Fedora 44 or newer and the current Arch Linux. The .deb refuses to install on Ubuntu 24.04 and older; the Flatpak runs there. The AppImage and the Flatpak use the GNOME 51 libraries.

Installing

Every release has packages for x86-64 Linux and a .dmg for Apple Silicon Macs. These are the files of Core Rules 1.2.0, the latest release; Windows 11 comes from the Microsoft Store:

System	Download	Install
macOS 14 or newer, Apple Silicon	CoreRules-1.2.0-arm64.dmg	Open it, drag Core Rules to Applications, then allow it to open
Fedora 44 or newer	corerules-1.2.0-1.fc44.x86_64.rpm	sudo dnf install ./corerules-1.2.0-1.fc44.x86_64.rpm
Ubuntu 26.04 or newer	corerules_1.2.0_amd64.deb	sudo apt install ./corerules_1.2.0_amd64.deb
Arch Linux, CachyOS, Omarchy	corerules-1.2.0-1-x86_64.pkg.tar.zst	sudo pacman -U ./corerules-1.2.0-1-x86_64.pkg.tar.zst
Any distribution with Flatpak, such as Bazzite	io.github.brahm.CoreRules.flatpakref, from the Flatpak repository	flatpak install --user https://brahm.github.io/corerules/io.github.brahm.CoreRules.flatpakref
Any distribution (glibc 2.43+)	CoreRules-1.2.0-x86_64.AppImage	chmod +x CoreRules-1.2.0-x86_64.AppImage, then run it
Community add-ons, for every system above	CoreRules-Community-Addons.zip	In Core Rules, Import Add-ons…, then pick the folder that holds the zip (how)

The release also has the CoreRules-1.2.0.flatpak file, the PKGBUILD of the pacman package and SHA256SUMS, the checksums of every file. Before 1.0 there were betas (0.x) and release candidates (-rc), marked as pre-releases on the releases page; the 1.2.0 packages replace 1.0.0 or a release candidate on update.

Users ran 1.0 on Fedora 45 beta (the .rpm), Ubuntu 26.10 (the .deb), Bazzite (the Flatpak and the AppImage, as on any Fedora Atomic desktop), Arch Linux and CachyOS (the pacman package). The release workflow also installs and starts every package on clean Ubuntu 26.04 and 26.10, Fedora 44 and 45, Arch Linux and CachyOS systems.

Ubuntu 24.04 and older releases are not supported: the .deb refuses to install there, and the Flatpak is the way to run the app on them.

The app is called Core Rules in the applications menu (corerules on the command line); the .deb, .rpm and pacman packages also install the cr command-line tool. The Flatpak uses the GNOME 51 runtime from Flathub and may read and write your home folder, where Wine keeps Core Rules, and CDs under /media and /run/media. The AppImage bundles the GNOME 51 libraries (GTK, libadwaita and the rest).

The pacman package is built on the current Arch Linux and fits the distributions that follow its repositories, such as CachyOS, Omarchy and EndeavourOS; update the system (sudo pacman -Syu) before installing it. Each release also has its PKGBUILD, which builds the package from the release's source with makepkg -si.

Windows 11

The Windows 11 version comes from the Microsoft Store, which signs the package, so Windows and Smart App Control install it without warnings. There is no direct download: the MSIX that the release workflow builds is not signed (the Store signs it), and Windows does not install an unsigned package. The Store also installs the Windows App Runtime that the app needs and brings every update.

The app keeps its data in Documents\Core Rules\data, copies the rules data from the CD or its ISO image with Extract Data from CD…, and also opens an installation of the original program on the same computer.

macOS

The Mac version is for Apple Silicon Macs (M1 or newer) with macOS 14 or newer. Download CoreRules-1.2.0-arm64.dmg, open it and drag Core Rules to Applications.

The app is signed without a certificate from Apple and is not notarized, because the project has no Apple developer account. So the first time you open it, macOS refuses it and says it could not check it. Run this once in Terminal. From then on it opens like any other app:

xattr -dr com.apple.quarantine "/Applications/Core Rules.app"

Without Terminal (the Open Anyway steps):

1. Open Core Rules once, and press Done when macOS refuses it.
2. Open System Settings › Privacy & Security.
3. Under Security, press Open Anyway next to "Core Rules", and confirm with your password.

Some Macs do not offer Open Anyway, and a Mac managed by a company or school may not allow the app at all. You need to do this again after each update.

The app keeps its data in ~/Library/Application Support/Core Rules/data. Macs have no CD drive, so Extract Data from CD… copies the rules data from the CD's ISO image or from a folder the CD's files were copied into. Open Folder… also opens an installation of the original.

The Flatpak repository

The project has its own Flatpak repository, at https://brahm.github.io/corerules/flatpak/ next to the website, signed with the project's key. It always holds the latest release: each new version reaches it when it is released, and flatpak update, GNOME Software and Discover bring it. The .flatpakref above adds the repository as the corerules remote, and Flathub for the GNOME runtime, and installs the app; on a desktop with GNOME Software or Discover, such as Bazzite, opening the downloaded file does the same. To add the repository yourself and install from it:

flatpak remote-add --user --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
flatpak remote-add --user --if-not-exists corerules https://brahm.github.io/corerules/corerules.flatpakrepo
flatpak install --user corerules io.github.brahm.CoreRules

The release's .flatpak file installs the app without the repository. From the release after 1.0.0 on, it also adds the repository, so that installation updates the same way. The CoreRules-1.0.0.flatpak file gets no updates; if you installed it, move to the repository once (your characters, settings and Core Rules installation stay):

flatpak uninstall --user io.github.brahm.CoreRules
flatpak install --user https://brahm.github.io/corerules/io.github.brahm.CoreRules.flatpakref

Getting the rules data

The app needs the rules data of a Core Rules CD you own (see You need the original discs). Copy what the app uses into a local data package once with Extract Data from CD… in the main menu, which the app also offers when it finds no data. Choose the CD's ISO image, read directly with no mounting or other tools, or the folder of the mounted CD, of an installation or of a Wine prefix. The same from the command line:

cr extract-data add_core_rules_2_expansion.iso   # the CD's ISO image
cr extract-data /media/$USER/EVERMORE            # the mounted CD
cr extract-data "$HOME/.wine"                    # Core Rules installed in Wine

The data goes into ~/.local/share/corerules/data, where the app and cr look first. If that folder is taken, the package goes next to it as corerules-data-core20 or corerules-data-expansion; the Expansion takes the data folder over from Core Rules 2.0 data, which moves aside, since the Expansion is where the app makes and changes things (2.0 content is brought in with Import Core Rules 2.0…). Use the Expansion disc for everything the app creates and edits. The package holds TSR/Wizards of the Coast content: keep it for your own use and do not redistribute it.

The app can also work directly on an existing installation: Open Folder… (Ctrl+O) takes any folder with a Database/ folder, such as $WINEPREFIX/drive_c/Program Files/AD&D Core Rules 2.0, and saves there, so the original program sees the changes. A folder the app cannot write to, such as the mounted Expansion CD or ISO image, is copied into ~/.local/share/corerules/data the first time it is opened, as Extract Data from CD… does, and characters and everything else made are saved in that copy; opening the CD again opens the copy. A Core Rules 2.0 CD opens read-only from the disc, as any 2.0 installation does.

Community add-ons

The Core Rules Community Add-ons Collection gathers 672 add-ons the community made for Core Rules 2.0 and the Expansion (races, classes, kits, spells, monsters, modules and the AD&D Core Rules User Database), converted to the Expansion's format and consolidated into 36,525 items, with the 668 pictures that came with them. Monster types, monsters, races and characters show those pictures in the app. It comes as one .zip, on every system the app runs on:

Download CoreRules-Community-Addons.zip

This link always gives the newest build; the addons release also keeps each version. To import it (Core Rules 1.2.0 or newer):

1. Put the zip in a folder of its own. There is no need to extract it.
2. In Core Rules, choose Import Add-ons… (the main menu on Linux, the More menu on Windows, the File menu on the Mac) and pick that folder.
3. Check the list of what comes in and press Import. The whole collection takes about a minute.

The collection's README says what is inside, how it was built and how to undo an import. A Linux installer (an AppImage) carried the add-ons until 1.1.0; Import Add-ons… replaces it.

Import Add-ons…, in the main menu on Linux, the More menu on Windows and the File menu on the Mac, brings in every add-on in a folder at once. The folder is searched with its subfolders and the ZIP archives in it (as the add-ons were shared), each .xpx and .xpt package is read and told apart by what it holds, and the list shows what comes in, what is found twice and what cannot be imported, with why, before anything is written. Import then copies the user databases and characters to a backup beside the data folder, imports the packages from the oldest file to the newest (characters already in the list are left out), copies the .bmp pictures to where the imported records look for them (or where a pictures.tsv beside them says), and writes a log of everything it did.

Reporting problems

Please open an issue for anything that crashes, saves something the original cannot open, or works differently from the original in a way the list above does not mention. Say which package you installed, which disc your data came from, and attach the character or package file when one is involved.

Development

Testing against your own installation

The rules databases are copyrighted and are not part of this repository. To check the readers against them, point CORERULES_DIR at an installed copy (the folder that holds Database/):

CORERULES_DIR="$HOME/.wine/drive_c/Program Files/AD&D Core Rules 2.0" cargo test

Layout

Crate	Purpose
cr-formats	Readers and writers for the original file formats, no UI
cr-store	Finds and opens an installation (case-insensitive paths) and builds the catalog the app shows
cr-cli	cr command for inspecting data
cr-i18n	Translations of the interface (po/*.po, built into the program)
cr-app	What both apps share above the backend, with no GTK and no Windows: the names of their actions, the library's search, filters and commands, the pictures, the help and About, the book reader's zoom, Find and reading positions, the sheet's options and exports, the sheet laid out on printed pages and the sheet as a PDF
cr-gtk	The GNOME app
cr-win	The Windows 11 app (WinUI 3 with windows-reactor), with every screen of the GNOME app

The backend crates and cr-app have no GTK dependency, and CI builds and tests them on Windows too, with cr-win and its MSIX package.

Both apps refer to their actions (menu items, buttons, shortcuts) only through the constants of cr_app::action, such as action::SHEET_PDF for sheet.pdf. cargo test -p cr-app fails when the GNOME app lacks one of them, or when the Windows app lacks one that NOT_YET_ON_WINDOWS does not list as still to port; a screen ported to Windows takes its actions off that list.

Languages

The app speaks the system's language when it is one of English (US), Português (Brasil), Español, Italiano, Français or Deutsch, and English otherwise. Preferences (Ctrl+,) can choose another language; the choice is kept in ~/.config/corerules/settings.ini and applies the next time the app starts. Only the interface is translated: spell, monster, item and class names and texts from the original files stay as they are, and so do the cr command, exports and character sheets.

Texts are wrapped where they are written (tr("Save"), tr!("Deleted {name}", name), trn!("{n} entry", "{n} entries", count)). cargo test fails while a wrapped text lacks a translation in any language; after adding or changing texts, run

cargo run -p cr-i18n --example update-po

to update crates/cr-i18n/po/corerules.pot and add the new entries to every catalog, then translate them in each .po.

Building

You need Rust 1.88 or newer, GTK 4.14 or newer and libadwaita 1.5 or newer.

On Fedora 44 or newer:

sudo dnf install cargo rust gcc gtk4-devel libadwaita-devel
cargo build --release
cargo test
./target/release/corerules

On Ubuntu 26.04 or newer (its packaged Rust may be too old, so use rustup):

sudo apt install build-essential libgtk-4-dev libadwaita-1-dev
cargo build --release
cargo test

On Arch Linux and the distributions built on it:

sudo pacman -S --needed base-devel cargo gtk4 libadwaita
cargo build --release
cargo test

To install a build system-wide, run packaging/install.sh / /usr/local as root after cargo build --release.

Packages

packaging/ builds every package (the .rpm, pacman package and Flatpak compile from source, the others package target/release):

packaging/deb/build.sh 0.1.0        # dist/corerules_0.1.0_amd64.deb (on Ubuntu 26.04)
packaging/rpm/build.sh 0.1.0        # dist/corerules-0.1.0-1.fc44.x86_64.rpm (on Fedora 44, needs rpm-build)
packaging/arch/build.sh 0.1.0       # dist/corerules-0.1.0-1-x86_64.pkg.tar.zst and its PKGBUILD (on Arch, not as root)
packaging/appimage/build-in-sdk.sh 0.1.0  # dist/CoreRules-0.1.0-x86_64.AppImage (in the GNOME 51 SDK)
flatpak-builder --user --install-deps-from=flathub --install build \
    packaging/flatpak/io.github.brahm.CoreRules.yml

The Packages workflow in GitHub Actions builds all five, installs each one on clean Ubuntu 26.04, 26.10 and latest, Fedora 44, 45 and latest, Arch Linux and CachyOS containers and starts the app there once in each of its six languages, checking that every text on screen is in that language (packaging/smoke-test.sh). Pushing a v* tag, or running the workflow with a tag, publishes them as a release; packaging/release-notes.md is its description. A tag with a suffix, such as v1.0.0-rc1, is published as a pre-release (a release candidate for -rc tags); the .deb and .rpm write the suffix with a tilde (1.0.0~rc1) and the pacman package drops the hyphen (1.0.0rc1), so that 1.0.0 sorts after it.

The website's Flatpak repository is built by the Landing page workflow (.github/workflows/pages.yml) each time it publishes the site: packaging/flatpak/repo.sh imports the .flatpak of the latest release into a new repository, signs it and writes corerules.flatpakrepo and io.github.brahm.CoreRules.flatpakref next to the page. After a final release, the Packages workflow starts the Landing page workflow, so the repository gets the new version without anyone touching it; republishing the same release changes nothing for installed apps. Both workflows sign with the key in the FLATPAK_GPG_PRIVATE_KEY secret, and the Packages workflow also writes the repository's address and key into the .flatpak. Without the secret, the .flatpak is unsigned and the site is not published (a pull request signs with a throwaway key to test the rest). The key has no passphrase and is made once:

gpg --batch --passphrase '' --quick-gen-key 'Core Rules Flatpak' rsa4096 sign never
gpg --armor --export-secret-keys 'Core Rules Flatpak'   # the secret's value

Keep a copy of it offline: with a new key, every installation has to add the repository again.

Running from a source checkout

Without a folder, the tools use the data package, then a Core Rules installation in $WINEPREFIX/drive_c/Program Files/AD&D Core Rules 2.0; they also take a folder:

cargo run -p cr-cli -- chars
cargo run -p cr-cli -- survey "/path/to/AD&D Core Rules 2.0"
cargo run -p cr-gtk                                # the data package or the Wine prefix
cargo run -p cr-gtk -- "/media/cdrom"               # or any folder with Database/

On Windows 11, with the Windows App Runtime 2.4 installed, the Windows app runs with cargo run -p cr-win; it opens the data package in Documents\Core Rules\data or the original's installation.

License

MIT, see LICENSE. AD&D and Advanced Dungeons & Dragons are trademarks of Wizards of the Coast; this project is not affiliated with them.