HardSet — Enforced Hardcore

A fourth world type that makes a hardcore run actually mean something.

Survival. Creative. Hardcore. And now HardSet — hardcore with the exits welded shut. If you've ever wanted to prove a hardcore run was legit — no quiet creative slip, no "oops, restored a backup after I died" — this is the mode built for exactly that.

What is HardSet?

HardSet adds a new option to the Create New World screen, right past Hardcore. A HardSet world plays like hardcore — one life, locked to Hard difficulty — but the mod actively shuts down the usual ways people fudge a run, and it keeps its own outside record of what happened so a death can't quietly be undone later.

It's made for streamers, YouTubers, challenge runners, and anyone who wants their hardcore world to be trustworthy — to themselves or to an audience.

What it does

Locks the run while you play

🚫 No commands. Every /command typed by a player is blocked — no /gamemode, no /give, no operator tricks.
🚫 No creative or adventure. You can't switch out of survival, by command, by F3+F4, or by packet.
🚫 No cheaty Open-to-LAN. Opening the world to LAN with "Allow Cheats" on is refused.
💀 Death sticks. When you die, you die — "Spectate World" works exactly like vanilla hardcore, and you can't claw your way back to survival.

Remembers what really happened

🧠 Outside witness. The mod keeps its own small, encrypted record of your world outside the world folder. Restore an old backup to undo a death and the world says you're alive — but the witness remembers, and the rollback is caught.
🔗 Stamp chain. Every save advances a tamper-resistant hash chain (Bitcoin-style), so the world's history can't be silently rewound or forged.
🪓 Self-healing. If those records get deleted, the mod notices and rewrites more of them — and a world that's lost its memory is flagged, not trusted.

Catches tampering when the mod comes back

⚠️ A CHEATED screen brands any world that's been rolled back, edited, or played while the mod was switched off. Take the mod out, cheat, put it back — the moment it loads, it knows.

Built for proof

📺 Streamer HUD. An optional on-screen stamp ID updates as you play. On camera, it becomes a receipt your viewers can't fake — a repeated or out-of-order ID is a public red flag.
📜 Tamper-evident log. Chat and key events are recorded in a chained log that can't be quietly edited after the fact.

How to use it

Install Fabric Loader, Fabric API, and HardSet (see Requirements).
Create New World → cycle the world-type button past Hardcore to HardSet.
Play. That's it. Everything else is automatic.

Honest about what it is (and isn't)

No single-player mod can be truly uncheatable — anyone willing to crack open the mod itself on their own PC can eventually get around anything. HardSet isn't built on that fantasy. It's built on a simpler, real promise: make cheating more work than just playing the game honestly, and catch it when it happens so a faked run can't pass as legit.

Against the casual cheat and the determined file-editor, that's a wall. Against a dedicated reverse-engineer, it's a tripwire that leaves evidence. That's the honest deal — and it's enough to make a HardSet world mean something.

This mod is closed-source on purpose — keeping the recipe private is part of how it raises the bar.

What it writes to your computer (full transparency)

To catch backup-restores, HardSet stores a few small, encrypted records outside your world folder (in your game, config, home, and temp directories). They only note that a given HardSet world exists and whether it has died — nothing personal, nothing about other worlds or files. This is the core anti-rollback feature working as intended.

Two things worth knowing:

Moving a HardSet world to a different PC (or deleting those records) will flag it as tampered — by design, a run is bound to the machine it was played on.
Honest survival/normal worlds are never touched; this only applies to worlds you create as HardSet.

Requirements

Minecraft 1.21.11
Fabric Loader 0.19.2 or newer
Fabric API
Java 21

Notes & compatibility

Designed for single-player hardcore runs.
Best run as a clean, dedicated profile. Mods that rewrite or back up world data in unusual ways may interfere with HardSet's tracking.
Built for 1.21.11. Other versions will come later.

HardSet — if you say you beat hardcore, now you can prove it.