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SecondBrain

SecondBrain

by sailex • Downloads: 0 • Followers: 0
Description
Gallery
Changelog
Versions

⚠️ Experimental Mod

SecondBrain

mod-logo

A Fabric mod that brings intelligent NPCs to your minecraft world. Create player-like characters controlled by LLMs that respond to your chat messages and perform basic player actions.

This mod works fully serverside. It must also be installed on a client for setup.

Requirements

  • Minecraft Version: 1.20.1/1.21.1
  • Running Ollama server OR Player2 App OR an OpenAi Key

Mod Installation

  1. Download the Mod:
    • Get the latest version of the SecondBrain mod from the Modrinth page.
  2. Install the Mod:
    • Place secondbrain.jar in your mods folder on your minecraft fabric server and client.
  3. Launch Minecraft:
    • Start the Minecraft client and the server, and you're ready!

Usage with Ollama/OpenAi

Note: Player must be an operator to execute the following commands

GUI

  • Open the gui with the /secondbrain command and create/spawn, despawn/delete or edit the NPCs there.
  • Also edit the base configuration there.

Commands (Deprecated)

Warning: This command uses default ollama/openai settings!

  1. Spawn NPCs:
    • Use the /secondbrain add <npcname> <openai|ollama> (currently only ollama is supported) command to create an NPC. (Example: `/secondbrain add sailex428 OLLAMA)
  2. Remove NPCs:
    • Use the /secondbrain remove <npcname> command to remove an NPC from the game world.

Interact with NPCs:

  • Just write in the chat to interact with the NPC.

Setup Ollama

Ollama (Local LLM)

  1. Download Ollama:

    • Visit Ollamas Website and download the installer for your operating system.
  2. Install and Run Ollama:

    • Follow the setup instructions to install.
    • Start Ollama and ensure it's running in the background.
  3. Connect to the Mod:

    • Use the gui to create/edit an NPC and put in the address to your ollama server (complete url with http://...; if you're running your ollama on your local pc then you can just use the one that's already typed in)

Setup OpenAi (Paid)

  1. Create API Key
    • Visit OpenAi's website, sign up/log in and create a API key
    • Copy the created key
  2. Use the Key in the mod
    • Open the GUI and create an NPC with the LLM Type OPENAI and paste key into the Key field. (The key wont be ever shared with any other clients that has access to the GUI, also not your client. It will be saved in a secondbrain config file on the server)

Usage with Player2 App

The mod will automatically sync the selected Characters from the player2 App to NPCs in your singleplayer world. If you updated a description/name in the player2 App you can sync these changes with the command /secondbrain player2 SYNC It's not possible to change any configs from the Character with this mod.

Interact with NPCs

  • Write messages in the chat or directly to a specific NPC
  • Press and hold alt (win) or opt (macOS) key to talk directly to the LLM/AI
  • Activate Text-To-Speech for any NPC in the config gui to hear the LLM/AI output

Setup Player2 (Free, Limited)

  1. Download Player2 App

  2. Start the App and select Characters

    • Start the downloaded App and select the Characters you wanna use as NPCs

License

This project is licensed under the LGPL-3.0

Disclaimer

Credits

This project utilizes components from the following projects:

Thank you to the developers of these projects for their amazing work!

All Versions

+ Add Version
Name Game version Platforms Published Downloads Actions
1.20.1
Fabric
6mo ago 1
1.21.1
Fabric
6mo ago 1
1.21.10
Fabric
6mo ago 1
1.21.11
Fabric
6mo ago 1
1.21.8
Fabric
6mo ago 1
1.21.11
Fabric
7mo ago 1
1.21.8
Fabric
11mo ago 1
1.21.10
Fabric
11mo ago 1
1.21.1
Fabric
11mo ago 1
1.20.1
Fabric
11mo ago 1
1.21.8
Fabric
11mo ago 1
1.21.10
Fabric
11mo ago 1
1.21.1
Fabric
11mo ago 1
1.20.1
Fabric
11mo ago 1
1.21.8
Fabric
11mo ago 1
1.21.1
Fabric
11mo ago 1
1.20.1
Fabric
11mo ago 1
1.21.8
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.1
Fabric
last yr. 1
1.21.8
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.1
Fabric
last yr. 1
1.21.8
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.1
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
1.21.3
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.20.x
Fabric
last yr. 1
1.21.1
Fabric
last yr. 1
1.21.3
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
1.20.4
Fabric
last yr. 1
# Changelog

All notable changes to this project will be documented in this file.

## [3.1.7] - 2026-04-18

### 🐛 Bug Fixes

  • Fix vulnerabilities
  • Stackoverlow error

### 💼 Other

  • Add publishAllVersions task
  • Merge branch 'add-mc-1-21-11-support'
  • Pin deps, add lock file
  • Bump version
  • Downgrade stonecutter

### 📚 Documentation

  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.7
  • Update changelog for version 3.1.7

### ⚙️ Miscellaneous Tasks

  • Update release task name



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.7] - 2026-04-18

### 🐛 Bug Fixes

  • Fix vulnerabilities
  • Stackoverlow error

### 💼 Other

  • Add publishAllVersions task
  • Merge branch 'add-mc-1-21-11-support'
  • Pin deps, add lock file
  • Bump version
  • Downgrade stonecutter

### 📚 Documentation

  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.7
  • Update changelog for version 3.1.7

### ⚙️ Miscellaneous Tasks

  • Update release task name



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.7] - 2026-04-18

### 🐛 Bug Fixes

  • Fix vulnerabilities
  • Stackoverlow error

### 💼 Other

  • Add publishAllVersions task
  • Merge branch 'add-mc-1-21-11-support'
  • Pin deps, add lock file
  • Bump version
  • Downgrade stonecutter

### 📚 Documentation

  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.7
  • Update changelog for version 3.1.7

### ⚙️ Miscellaneous Tasks

  • Update release task name



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.7] - 2026-04-18

### 🐛 Bug Fixes

  • Fix vulnerabilities
  • Stackoverlow error

### 💼 Other

  • Add publishAllVersions task
  • Merge branch 'add-mc-1-21-11-support'
  • Pin deps, add lock file
  • Bump version
  • Downgrade stonecutter

### 📚 Documentation

  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.7
  • Update changelog for version 3.1.7

### ⚙️ Miscellaneous Tasks

  • Update release task name



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.7] - 2026-04-18

### 🐛 Bug Fixes

  • Fix vulnerabilities
  • Stackoverlow error

### 💼 Other

  • Add publishAllVersions task
  • Merge branch 'add-mc-1-21-11-support'
  • Pin deps, add lock file
  • Bump version
  • Downgrade stonecutter

### 📚 Documentation

  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.6
  • Update changelog for version 3.1.7
  • Update changelog for version 3.1.7

### ⚙️ Miscellaneous Tasks

  • Update release task name



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.6] - 2026-03-25

### 🚀 Features

  • Add mc 1.21.11 support
  • Impl versioned components/containers

### 💼 Other

  • Bump loom to 1.15
  • Bump gradle
  • Bump carpet and owo-lib
  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.5] - 2025-12-06

### 🚀 Features

  • Use llama3.2 as default model

### 🐛 Bug Fixes

  • Query does not returns results error
  • Parsing error using smaller models

### 💼 Other

  • Add mcVersion to display name of gh release
  • Optimizations for small models

### 📚 Documentation

  • Update changelog for version 3.1.4
  • Update changelog for version 3.1.5

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.5] - 2025-12-06

### 🚀 Features

  • Use llama3.2 as default model

### 🐛 Bug Fixes

  • Query does not returns results error
  • Parsing error using smaller models

### 💼 Other

  • Add mcVersion to display name of gh release
  • Optimizations for small models

### 📚 Documentation

  • Update changelog for version 3.1.4
  • Update changelog for version 3.1.5

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.5] - 2025-12-06

### 🚀 Features

  • Use llama3.2 as default model

### 🐛 Bug Fixes

  • Query does not returns results error
  • Parsing error using smaller models

### 💼 Other

  • Add mcVersion to display name of gh release
  • Optimizations for small models

### 📚 Documentation

  • Update changelog for version 3.1.4
  • Update changelog for version 3.1.5

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.5] - 2025-12-06

### 🚀 Features

  • Use llama3.2 as default model

### 🐛 Bug Fixes

  • Query does not returns results error
  • Parsing error using smaller models

### 💼 Other

  • Add mcVersion to display name of gh release
  • Optimizations for small models

### 📚 Documentation

  • Update changelog for version 3.1.4
  • Update changelog for version 3.1.5

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.4] - 2025-11-23

### 🚀 Features

  • Update mineskin resolving to mc 1.21.10
  • Add npc name validation

### 🐛 Bug Fixes

  • Prevent currentModificationException of playerList when removing npcs
  • NoSuchElement exception thrown if npcConfig not present
  • Fix couple runtime issues

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.4] - 2025-11-23

### 🚀 Features

  • Update mineskin resolving to mc 1.21.10
  • Add npc name validation

### 🐛 Bug Fixes

  • Prevent currentModificationException of playerList when removing npcs
  • NoSuchElement exception thrown if npcConfig not present
  • Fix couple runtime issues

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.4] - 2025-11-23

### 🚀 Features

  • Update mineskin resolving to mc 1.21.10
  • Add npc name validation

### 🐛 Bug Fixes

  • Prevent currentModificationException of playerList when removing npcs
  • NoSuchElement exception thrown if npcConfig not present
  • Fix couple runtime issues

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.4] - 2025-11-23

### 🚀 Features

  • Update mineskin resolving to mc 1.21.10
  • Add npc name validation

### 🐛 Bug Fixes

  • Prevent currentModificationException of playerList when removing npcs
  • NoSuchElement exception thrown if npcConfig not present
  • Fix couple runtime issues

### ⚙️ Miscellaneous Tasks

  • Bump version



# Changelog

All notable changes to this project will be documented in this file.

## [3.1.2] - 2025-11-16

### 🚀 Features

  • Update error handling -> log only rootcause into chat

### 📚 Documentation

  • Update changelog for version 3.1.1

### ⚙️ Miscellaneous Tasks

  • Bump version

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [3.1.2] - 2025-11-16

### 🚀 Features

  • Update error handling -> log only rootcause into chat

### 📚 Documentation

  • Update changelog for version 3.1.1

### ⚙️ Miscellaneous Tasks

  • Bump version

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [3.1.2] - 2025-11-16

### 🚀 Features

  • Update error handling -> log only rootcause into chat

### 📚 Documentation

  • Update changelog for version 3.1.1

### ⚙️ Miscellaneous Tasks

  • Bump version

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [3.1.1] - 2025-11-15

### 🚀 Features

  • Add mineSkinProxyClient
  • Apply skins from player2 on npc

### 💼 Other

  • Add skin loader for player2 -> main

### ⚙️ Miscellaneous Tasks

  • Bump version
  • Use publishMods task for publishing

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).
# Changelog

All notable changes to this project will be documented in this file.

## [3.1.1] - 2025-11-15

### 🚀 Features

  • Add mineSkinProxyClient
  • Apply skins from player2 on npc

### 💼 Other

  • Add skin loader for player2 -> main

### ⚙️ Miscellaneous Tasks

  • Bump version
  • Use publishMods task for publishing

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).
# Changelog

All notable changes to this project will be documented in this file.

## [3.1.1] - 2025-11-15

### 🚀 Features

  • Add mineSkinProxyClient
  • Apply skins from player2 on npc

### 💼 Other

  • Add skin loader for player2 -> main

### ⚙️ Miscellaneous Tasks

  • Bump version
  • Use publishMods task for publishing

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).
# Changelog

All notable changes to this project will be documented in this file.

## [3.0.1] - 2025-10-26

### 🐛 Bug Fixes

  • Fix attacking doesnt work

### ⚙️ Miscellaneous Tasks

  • Bump engine version
  • Bump version
  • Add CURSEFORGE_API_KEY to publish workflow
  • Use publishMods task in publish workflow

# Changelog

All notable changes to this project will be documented in this file.

## [3.0.1] - 2025-10-26

### 🐛 Bug Fixes

  • Fix attacking doesnt work

### ⚙️ Miscellaneous Tasks

  • Bump engine version
  • Bump version
  • Add CURSEFORGE_API_KEY to publish workflow
  • Use publishMods task in publish workflow

# Changelog

All notable changes to this project will be documented in this file.

## [3.0.1] - 2025-10-26

### 🐛 Bug Fixes

  • Fix attacking doesnt work

### ⚙️ Miscellaneous Tasks

  • Bump engine version
  • Bump version
  • Add CURSEFORGE_API_KEY to publish workflow
  • Use publishMods task in publish workflow

# Changelog

All notable changes to this project will be documented in this file.

## [3.0.0] - 2025-10-25

  • Bump engine to 1.21.8

# Changelog

All notable changes to this project will be documented in this file.

## [3.0.0] - 2025-10-20

  • Bump engine to 1.21.1


# Changelog

All notable changes to this project will be documented in this file.

## [3.0.0] - 2025-10-19

### 🚀 Features

  • Add system prompt input in configScreen for openai
  • Add model input to screen
  • Add saved messages (from db) to conversationHistory
  • Add deleting convos when NPC has been deleted
  • Add error handling for commandErrors

### 🐛 Bug Fixes

  • Error loading resources when internal server didnt started yet
  • Chiseled gradle task doesnt exist anymore
  • Fix gradle not found
  • Fix gradle not found
  • Typo in gradle task
  • Couldnt find timestamp column sql error
  • Mojmap issues when using carpet
  • Role doesnt exists
  • Player2api content field missing
  • Cannot parse player2api response, index field missing
  • To many fields unnecessary fields are in the response
  • Prevent some nullpointers
  • Rejoin in world crashes client
  • Npcs doesnt spawn
  • Can only manipulate existing players
  • Model field is shown in player2 config
  • Prevent classCastError
  • ApiKey overwritten with default string
  • ModelInput is shown twice
  • Api key is overwritten when updating on client with default text
  • Prevent exceptions when spawning an npc that already exists
  • Api key still overwritten
  • Convos not saved
  • Prevent printing several times same response
  • Prevent printing several times same response
  • Fix-runtime-mismatch-class-file-versions (#43)

### 💼 Other

  • Integrate to structured output -> dev (#39)
  • Integrate secondbrainengine -> main
  • Add publish gradle tasks
  • Mc 1.21.8 support -> main
  • Use java 17 for older versions
  • Downgrade to java 17
  • Use java17 for older mc versions -> main
  • Up wispforest deps

### 🚜 Refactor

  • Remove recipeRepo
  • Remove npc modes
  • Remove some more unnecessary stuff
  • Remove more unuseful stuff
  • Make networkHandler 1.20 compatible
  • Main class, npcFactory
  • ResourceProvider
  • ConversationHistory
  • Function calling api
  • Add getItems function for testing
  • Make sttHudElement 1.20.1 compatible
  • Adjust system, summary and init prompt
  • Tweak prompts
  • Add commands to system prompt
  • Set owner on controller
  • Switch to using structured output
  • Remove functionCallable interface
  • Rename player2 types
  • Remove functionCalling completely
  • Add openAiClient again
  • Build script
  • Check llm reachable before spawn npc
  • Remove print exception message into game chat

### 📚 Documentation

  • Update readme

### 🧪 Testing

  • Add latest mc version (1.21.8)
  • Use latest git-cliff-action

### ⚙️ Miscellaneous Tasks

  • Bump stonecutter version
  • Add secondbrainengine dep
  • Remove gradle properties for 1.20.4 and 1.21.3
  • Up some deps
  • Up fabric loader
  • Add secondbrainengine 1.21.1
  • Add carpet
  • Switch back to engine 1.1.2
  • Up fapi + engine
  • Add support for mc version 1.21.8
  • Bump loom, gradle wrapper
  • Add publish task
  • Bump version
  • Remove not available avatar pic
  • Update publish workflow
  • Add java 17 compiled engine
  • Bump engine
  • Publish only 1.20.1

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [2.1.2] - 2025-07-05

### 🚀 Features

  • Register client/server prodTest gradle task

### 🐛 Bug Fixes

  • Fix workflow_run has no referenced wf
  • Fix built-jars missing in runTime test job
  • Fix gradle wrapper not found

### 💼 Other

  • Add missing httpcomponents dep



### 🚜 Refactor

  • Refactor runTimeTest workflow

### 📚 Documentation

  • Adjust heights of headings

### 🧪 Testing

  • Add prod runTime test
  • Add gradle setup to runTime test
  • Comment out the prod runtime test

### ⚙️ Miscellaneous Tasks

  • Up fabric loom
  • Up gradle wrapper
  • Put all deps in the jar
  • Run runTimeTest after every completed build
  • Make gradlew executable
  • Add java setup
  • Add right apache lib
  • Bump version

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [2.1.1] - 2025-05-30

### 🐛 Bug Fixes

  • Optimize responsiveness
  • Only provide top six relevant functions
  • Adjust dropItem function description and player2 systemprompt

### 💼 Other

  • Optimize responsiveness -> main


  • Optimize systemprompt -> main



### 📚 Documentation

  • Update changelog for version 2.1.0

### ⚙️ Miscellaneous Tasks

  • Bump version

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [2.1.0] - 2025-05-28

### 🚀 Features

  • Implement Player2APIClient for communicating with player2 service
  • Add verbose config option
  • Impl functionCalling in player2Client
  • Add player2 character synchronizing at server start
  • Add player2ActionCommand to make manual char sync possible
  • Add tts and stt
  • Add healthchecker
  • Add llmType specific icon in config gui for every npc
  • Add checkbox for tts to gui
  • Put history into top of user prompt
  • Add feedback on press of sttkey
  • Add init prompt of player2 npcs
  • Feat: optimize conversationhistory
  • add user prompt and responses to conversation history in own message object
  • adjust response types that prompting works with new player2 api changes
  • adjust system prompt for player2


### 🐛 Bug Fixes

  • Remove unused imports
  • Add more meaningful error message
  • Deleting instead of removing npcs at sync
  • Move health checking into npcSynchronizer
  • Prevent null pointer
  • Only add header if not empty
  • Npc cant get respawned
  • Add missing fields in pojo that are not documented but still in the response
  • Wrong json structure of functions
  • Use uuid of entity instead of the one of the config
  • Put uuid in deletePacket instead of name
  • Make textures get shown right
  • Dont listen to own chat messages
  • Messages doesnt got added to chatRequest
  • Skinurl after respawn null
  • Encoding issue caused by null strings
  • Prevent llmExceptions while performing stt actions
  • Add npcName to stt error log
  • Prevent executor isTerminated status
  • Use correct endpoint on stt stop
  • Add better error handling for stt requests
  • Fix: smaller ui issues
  • add scrollable container to npc screen so that multiple ones can get shown
  • adjust timeout label in baseConfigScreen

  • Timeout from baseConfig now also gets used from player2 client
  • Make config editable of player2 also if npc is active
  • Prevent some concurrent modification exceptions
  • Remove some unnecessary logs + fix translations
  • Use heartbeat api to check if service is reachable

### 💼 Other

  • Integration player2 -> main



### 🚜 Refactor

  • Refactor publish and build workflow
  • Use consistent package structure
  • Use uuid as id for every config instead of npcName
  • CheckServiceIsAvail, remove url arg
  • Llmtype specific icons in npc label (gui)
  • IsReachable method in player2Client
  • Error handling and logging
  • Cleanup npc spawning
  • Use string template to add more context to messages in conversationHistory
  • Mr review adjustments

### 📚 Documentation

  • Update README.md
  • Add some java docs
  • Update readme to player2 integration

### 🎨 Styling

  • Remove spotless

### ⚙️ Miscellaneous Tasks

  • Remove spotless from pipe
  • Bump version

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

# Changelog

All notable changes to this project will be documented in this file.

## [2.0.3] - 2025-05-02

### 🐛 Bug Fixes

  • Runtime issues of automatone in singleplayer

### 📚 Documentation

  • Add footer git cliff config
  • Update readme

### ⚙️ Miscellaneous Tasks

  • Add publish workflow
  • Bump dawidd6/action-download-artifact from 2 to 6 in /.github/workflows

Download the new release on [Modrinth](https://modrinth.com/mod/secondbrain/versions).

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