Memento: Build History

MEMENTO

Minecraft remembers what you did.

Build without fear.

MEMENTO adds a player-focused history system to Minecraft.

Placed the wrong blocks?
Destroyed part of your build by accident?
Want to return to an earlier point in your project?

MEMENTO remembers your actions and lets you safely Preview, Undo, and Redo them without turning Minecraft into a world editor.

See what will change before you restore anything.

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✦ Undo your mistakes

Press Z to undo your latest action.

MEMENTO groups individual block changes into meaningful actions, so building a wall or digging an area can become one history entry instead of dozens of unrelated blocks.

Press Y to redo an action you previously undid.

Undo an entire building action in seconds.

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✦ See your history

Press H to open the MEMENTO History.

Instead of showing raw block updates, MEMENTO presents your actions as a readable timeline.

From there you can:

• inspect previous actions
• preview them
• undo them
• redo compatible changes
• see conflicts
• create Memories

Every action becomes part of your personal build history.

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✦ Preview before restoring

Not sure what an Undo will change?

Open Preview first.

MEMENTO displays ghost blocks in the world so you can see what would be restored before anything is actually changed.

Preview is client-side and does not modify the world.

Preview first. Restore only when you're sure.

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✦ Memories

A Memory marks a point in your history.

Create one before starting a large build, renovation, or experiment.

Later, MEMENTO can determine which operations happened after that Memory and safely restore what is still recoverable.

Memories are logical history checkpoints — they are not full world backups.

Mark important moments in your build and return to them later.

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✦ Safe partial restoration

Minecraft worlds keep changing.

If part of an old operation has been modified later, MEMENTO does not blindly overwrite the current world.

For example:

48 blocks in the original operation
43 safely restored
5 left untouched because they changed later

MEMENTO tells you what happened instead of pretending the restore was perfect.

MEMENTO restores what is safe and leaves conflicts untouched.

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✦ Multiplayer-aware

MEMENTO is designed with multiplayer safety in mind.

If Player A builds something and Player B later changes one of those blocks, Player A's Undo will not simply overwrite Player B's later work.

The server validates restores against the current world before applying them.

The client never decides what the world should become.

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✦ Resource conservation

MEMENTO is not Creative-mode materialization disguised as Undo.

Where MEMENTO can safely account for items, restoring changes respects item conservation.

If the mod cannot prove that an operation can be restored safely, it fails closed instead of guessing.

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Controls

Key	Action
Z	Undo
Y	Redo
H	Open MEMENTO History

All keybindings can be changed in Minecraft's Controls menu.

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Current supported version

Minecraft 26.2

• Fabric Loader 0.19.5
• Fabric API 0.159.0+26.2
• Java 25
• Fabric API is required

For the full MEMENTO interface, install the mod on both the server and client.

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Current limits

MEMENTO 1.0 uses conservative fixed limits that were tested as part of its release:

• up to 4,096 changes per reversible operation
• up to 500 operations per player
• 7-day history retention
• up to 20 Memories per player
• up to 20,000 Preview ghost blocks

Configuration is planned for a later version.

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What MEMENTO is not

MEMENTO is intentionally not a complete world rewind system.

It focuses on restoring player-authored actions safely.

Autonomous world consequences such as:

• piston movement
• falling blocks
• redstone consequences
• explosions

may occur outside the recorded player operation and are not guaranteed to be restored.

Fluid propagation is currently outside the verified v1 guarantee.

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Crash safety

MEMENTO uses persistent history and recovery information so an interrupted restore does not automatically continue based on assumptions.

If Minecraft or the server crashes during a restore, MEMENTO verifies the world again before allowing further restoration.

If item accounting becomes uncertain after a crash, that operation may remain permanently blocked rather than risking item duplication.

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Philosophy

MEMENTO follows one important rule:

If the mod cannot prove that restoring something is safe, it does not guess.

That means a restore may occasionally leave something untouched.

That is intentional.

Keeping your world safe is more important than forcing every Undo to succeed.

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Version

MEMENTO 1.0.0 — Minecraft 26.2 / Fabric