Vault Forecast

About

VaultForecast is a client-side Fabric mod that predicts upcoming normal and ominous trial-vault rewards using the world seed. Unlike a simple “next drop” calculator, VaultForecast can maintain synchronization even when other players open vaults between your observations. It keeps multiple possible positions in the global reward sequence and eliminates incorrect candidates as more vault drops are observed. I don't want to go into the details of how the mod works; you can always check the source code :)

Quick start

1. Obtain the world seed

VaultForecast requires the exact seed used by the world.

2. Load the reward sequences

Use:

/vaultp seed <seed> <count> <method>

Example:

/vaultp seed 1871430171840862640 5000 fast

A count of 5000 loads:

5000 normal-vault drops 5000 ominous-vault drops

The count is applied separately to both sequences, not divided between them.

For a new or lightly used server, several thousand drops should normally be enough. Older or highly active servers may require a larger sequence because the current global position could already be far into it.

3. Choose a generation method

Fast method — recommended The fast method recreates Minecraft’s named RandomSequence and vault loot generation directly inside the mod.

Server method — beta trash

The server method launches a separate official vanilla Minecraft server locally and asks Minecraft itself to generate the reward sequences.

4. Open vault(s)

No way

5. Observe vault

DO NOT PICK UP THE LOOT IMMEDIATELY, WAIT UNTIL EJECT FINISH

When a opened vault ejects its complete reward, VaultForecast converts the reward into a canonical drop and compares it with the generated sequence.

After the first observation, several positions may match because identical rewards can appear more than once.

Each additional observation removes positions that can no longer be correct:

First observation → many possible candidates Second observation → fewer candidates Further observations → one exact candidate

Once only one candidate remains, the predictor knows the current global position for that vault type and can display upcoming rewards.

Normal and ominous vaults use independent sequences and are synchronized separately.

7. View upcoming rewards

Now you can view server's future drops

/vaultp get <vault type> [<how many>]

Search for a specific reward

/vaultp find <vault type> <reward>

The find command searches forward from the current synchronized position.

It does not search from the beginning of the sequence, so the result represents the next matching future reward rather than an item that was already consumed.

Normal and ominous vaults have different supported search targets. For example, normal-vault searches can include Tridents and Ominous Bottles, while ominous-vault searches can include Heavy Cores and Wind Burst books.

Directly watching other players

/vaultp watch

Look directly at the vault that you want the mod to observe, then use the watch command. It will synchronize exactly as if you had done it yourself.

Other players and maximum gap

/vaultp maxGap <gap>

VaultForecast cannot directly see every vault opening happening anywhere on a multiplayer server. Instead, it allows a configurable number of unknown openings between two known observations.

This value is called maxGap (<-- thats integer).

For example:

Previous observation: #1790 Other players open 80 vaults Your next observation: #1871 maxGap: 100

Because the number of missed openings is within the configured gap, VaultForecast can continue searching from the previous candidates and recover the new position.

A larger gap tolerates more unknown openings, but it can also produce more temporary candidates because a larger part of the sequence is searched.

Other commands

• /vaultp reset - resets all data about this session
• /vaultp forget - resets all currently watching vaults
• /vaultp count - returns amount of loaded drops for this sessions
• /vaultp load <count> <method> - same as /vaultp seed, but already with saved seed for this session