3d6

A small native Mac app for Old-School Essentials characters. The sheet fills in what the rules decide (saves, attacks, AC, movement, level-ups) and keeps every character in a plain Markdown file with a YAML header.

Website: soggybag.github.io/Character-Sheets

Try the beta

The app is in open beta on TestFlight: Join the beta

• You need macOS 15 or later and Apple's TestFlight app (the link offers it).
• Requires Old-School Essentials. The app knows the Classic Fantasy classes' numbers; the rules themselves are in the books.
• It's a beta: keep copies of characters you care about. Each one is a plain text file, so a backup is just a copy of the file.
• Send feedback from Help → Send Feedback… in the app, with TestFlight's screenshot feedback, or by opening an issue here.

3d6 is an independent app. It isn't an official Old-School Essentials product, and isn't affiliated with or approved by Necrotic Gnome. Old-School Essentials is a trademark of Necrotic Gnome. The trademark and Old-School Essentials logo are used with permission of Necrotic Gnome, under license.

Docs

• Plan and roadmap: docs/PLAN.md
• File format: docs/FILE-FORMAT.md
• PDF import notes: docs/PDF-IMPORT.md

Layout

Path	What
App/	The macOS app (SwiftUI, document-based). Files added here are picked up by Xcode automatically.
Config/	Info.plist (document types) and entitlements
Packages/CharacterKit/	Reading and writing character files. No UI; shared with a future iPad app.
Packages/CharacterKit/Sources/CharacterKit/Resources/ose/	OSE Classic rules data (JSON), bundled with the app
schema/	JSON Schema for the file header
examples/	Example characters. Also test fixtures: every file must round-trip byte for byte.

Build and test

Requires Xcode 16 or later. The app runs on macOS 15+.

# App
open "Character Sheets.xcodeproj"        # then Run (⌘R)

# CharacterKit tests (or choose the CharacterKit scheme in Xcode and press ⌘U)
cd Packages/CharacterKit && swift test

The Xcode project and scheme are still named Character Sheets; the app builds as 3d6.app. The bundle id is com.mitchellhudson.CharacterSheets, signed automatically with team 753UQ7TNXJ. To send a build to TestFlight, run scripts/testflight.sh (see docs/RELEASING.md).

Third-party notices (Yams, MIT; OSE SRD rules data, OGL 1.0a; the Old-School Essentials third-party license) are in App/Help/Legal.swift, shown in About and Help → Licenses and Legal. The full OGL text ships in the CharacterKit resource bundle.