Echo Protocol

# Echo Protocol

Echo Protocol is a psychological horror mod for Minecraft that makes the world remember the player.

The mod records short, bounded fragments of player movement and later recreates them as unsettling Echoes. At first, they simply repeat the past. Over time, they begin to make mistakes, copy the present, move independently, and act as though the world belongs to them.

## Echo Types

### Memory Echo

Replays a previous route from the player's recorded movement history. It does not react or attack and behaves like a distant memory.

### Corrupted Echo

Begins by replaying the past, but gradually desynchronizes. It may freeze, turn toward the player, move closer while unobserved, hide, or disappear.

### Mimic Echo

Copies the player's current movement with a delay. Its imitation becomes less accurate over time, and rare hostile encounters may occur.

### The Original

A rare late-game Echo that no longer copies the player.

The Original remembers familiar locations such as beds, storage areas, crafting spaces, doors, portals, and common idle positions. It moves independently and behaves as though the player is the duplicate.

## Features

- Real player skins
- Classic and slim player model support
- Four different Echo types
- Persistent horror progression
- Familiar-location tracking
- Safe server-controlled spawning
- Configurable sounds and visual effects
- Reduced flashing and reduced visual effects options
- English and Russian localization
- Dedicated server support
- Multiplayer privacy
- Advancements and administrator testing commands

## Multiplayer Privacy

Private Echoes are server-filtered by default.

When shared Echoes are disabled, unrelated players do not receive the private Echo entity, replay information, particles, sounds, text events, or familiar-location data.

## Requirements

- Minecraft Java Edition 1.21.1
- Fabric Loader 0.16.14 or newer
- Fabric API
- Java 21

The mod must be installed on both the client and the server.

## Configuration

The configuration file is generated at:

`config/echo_protocol.json`

Event timing, Echo types, damage, visual effects, sounds, privacy, Stage 3 requirements, and accessibility options can be configured.

## Alpha Notice

Echo Protocol is currently in alpha.

The main systems are playable and manually tested, but event balance, configuration defaults, behavior, and save data may change in future versions.

## Known Limitations

- Echo movement is scripted rather than using advanced navigation.
- Recorded movement routes are not preserved across server restarts.
- Familiar-location detection uses bounded heuristics.
- The current sound design mostly uses compatible vanilla sound events.