OPAC - Essentials is an addon for Open Parties and Claims, developed for the Brassworks SMP. It expands the original OPAC - Better Commands project with configurable short commands, party chat, fine-grained claim permissions and Xaero's World Map integration for Minecraft 1.21.1.

Manage access to individual blocks, block entities, entities and throwable items through an in-game screen or commands while keeping OPAC in control of claims and parties. Search for claim owners directly from Xaero's World Map, jump to their claims and cycle through disconnected claim clusters.

⚠ WARNING

OPAC - Essentials is currently in ALPHA. Features, commands, configuration values, saved data and user interfaces may change between releases. Back up your world before updating and test new versions before using them on a production server.

Version 2.0

Version 2.0 renames and expands OPAC - Better Commands into OPAC - Essentials and starts the new, configurable generation of the project.

Every release before 2.0 belongs to the legacy version of the mod. Those releases use the old OPAC - Better Commands name and only provide fixed command features. They do not include configurable command names or the expanded 2.0 permission system and roadmap.

Features

• Configurable names for every command added by OPAC - Essentials
• Short aliases for commonly used OPAC commands
  • /claims for claim management
  • /party for party management
• Argument-free /claim and /unclaim commands
  • /claim claims the chunk in which the player is standing
  • /unclaim unclaims the chunk in which the player is standing
  • Coordinates and additional chunk arguments are intentionally not accepted
• Party chat with direct messages, toggle and status commands
• In-game claim permission screen through /claims permissions
• Separate permissions for main claims and subclaims
• Permissions for all players or a specific player
• Registry-aware search and suggestions for modded content
• Claim owner search directly in Xaero's World Map
  • Centers the map on the first matching claim cluster
  • Previous and next controls cycle through disconnected claim clusters
  • The currently selected cluster receives a highly visible outline
  • Incremental snapshots and asynchronous cluster calculation reduce client-side lag with large claim counts
  • The search button automatically adapts to different Xaero's World Map layouts

Command Configuration

Command names can be changed in:

config/opac_essentials-commands.toml

Default configuration:

[commands]
claims = "claims"
party = "party"
claim = "claim"
unclaim = "unclaim"
party_chat = "pchat"

Command names may contain 1-32 lowercase letters, numbers, underscores or hyphens. Each configured command must use a unique name and must not conflict with a command registered by another mod. A full server restart is required after changing the configuration.

Claim Permissions

Claim owners can grant exceptions for individual registry entries instead of opening an entire claim.

Target	Available actions
Blocks	Interact, break and place
Block entities	Interact and break
Entities	Interact and attack
Throwable items and projectiles	Throwable

Permissions can apply to either all players or one selected player. To manage them, stand inside a claim or subclaim you own and run the configured claims command followed by permissions:

/claims permissions

The same permissions can also be listed, added and removed through the command tree.

Party Chat

Using the default command names:

/pchat <message>
/pchat toggle
/pchat status

Party messages use OPAC's native handling and formatting. Errors returned by OPAC are passed through to the player.

Xaero's World Map Claim Search

When Xaero's World Map is installed, a search button is added to the World Map interface. Enter a player's name to center the map on that player's first claim cluster. If the player owns multiple disconnected clusters, use the previous and next controls below the search field to cycle between them.

The selected cluster is marked with a fixed, high-visibility outline that remains recognizable regardless of the owner's configured claim color. Claim data is copied incrementally on the client thread, while cluster calculation runs asynchronously on an immutable snapshot. Xaero and OPAC's mutable state and rendering remain on their original threads to avoid data corruption.

Requirements and Compatibility

• Minecraft 1.21.1
• NeoForge 21.1.216 or newer within the 21.1 release line
• Open Parties and Claims 0.25.8 or newer
• Xaero's World Map for the optional claim search interface

OPAC - Essentials contains a compatibility layer for both OPAC API v1 and API v2. This keeps older supported OPAC releases using API v1 compatible while allowing newer API v2 releases to work without a separate build.

Both the client and server need the mod when using the permission UI and its network features. The Xaero claim search itself is a client-side World Map integration.

Planned Features

The following features are planned and may change during ALPHA development:

• Complete overhaul of the OPAC claim and party interfaces
• A unified UI for claims, subclaims, parties and permissions
• More permission targets and actions
• Party-, rank- and group-based permission rules
• Improved permission search, filtering and bulk editing
• Permission import, export and migration tools
• More configuration options and localization support

Roadmap entries are goals, not guarantees. Their scope and release order may change based on testing, OPAC API changes and community feedback.

Development Status

OPAC - Essentials is under active development and should be treated as experimental software. Please include the Minecraft, NeoForge, OPAC, OPAC - Essentials and Xaero's World Map versions when reporting an issue.

License

Licensed under the Apache License 2.0. You may use, modify and redistribute this software under the terms of that license.

Credits

• Development and design by DerErneuerer
• Created for the Brassworks SMP
• Built as an addon for Open Parties and Claims

Links

• Project repository
• Brassworks SMP website
• Open Parties and Claims repository