subnautica-2-deep-synergy-coop-mod

Q: How do I install subnautica-2-deep-synergy-coop-mod?

Run npx skills add https://github.com/reason-machines/devtools-skills --skill subnautica-2-deep-synergy-coop-mod in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/subnautica-2-deep-synergy-coop-mod/ (personal) or .claude/skills/subnautica-2-deep-synergy-coop-mod/ (project).

by reason-machines

BepInEx-based cooperative multiplayer mod for Subnautica 2 with synchronized sessions, shared inventory, and AI-enhanced narrative generation

Installs: 227
Last 24h: —
Trending rank: —
Security: Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/reason-machines/devtools-skills --skill subnautica-2-deep-synergy-coop-mod

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads subnautica-2-deep-synergy-coop-mod automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Subnautica 2 Deep Synergy Coop Mod

Skill by ara.so — Devtools Skills collection.

Overview

Deep Synergy is a BepInEx-based cooperative multiplayer modification for Subnautica 2 that transforms the single-player survival experience into a synchronized multi-player session. The mod implements deterministic session synchronization (DSS), adaptive dynamic scaling (ADS), and decentralized peer-to-peer networking to enable seamless co-op gameplay without central server infrastructure.

Key Capabilities:

Synchronized world state across multiple clients using Merkle tree inventory tracking
WebRTC-based peer-to-peer networking with NAT punch-through
Hot-reloadable BepInEx plugin architecture (IL2CPP hooks)
Optional OpenAI/Claude API integration for dynamic narrative generation
Cross-platform support (Windows, macOS, Linux/Steam Deck)
Adaptive difficulty scaling based on player count

Installation

Prerequisites

Install BepInEx 6.0.x for Subnautica 2:
- Download BepInEx from the official repository
- Extract to Subnautica 2 game root directory
- Launch game once to generate BepInEx folder structure
Download Deep Synergy Mod:
- Obtain from the project repository
- Extract contents to <game_root>/BepInEx/plugins/

Directory Structure

Subnautica2/
├── BepInEx/
│   ├── plugins/
│   │   ├── DeepSynergyCore.dll
│   │   ├── SessionManager.dll
│   │   ├── StateSynchronizer.dll
│   │   └── ConflictResolver.dll
│   ├── config/
│   │   ├── synergy_profile.json
│   │   └── session_config.xml
│   └── LogOutput.log
└── Subnautica2.exe

First Launch

# Launch via Steam or direct executable
# BepInEx will patch the game on first run
# Check BepInEx/LogOutput.log for successful mod loading

Expected log output:

[Info   :   BepInEx] BepInEx 6.0.0 - Subnautica2 (5/14/2026)
[Info   :DeepSynergy] Deep Synergy Multiplayer Mod v1.0.0 loaded
[Info   :DeepSynergy] Session Manager initialized
[Info   :DeepSynergy] WebRTC transport layer ready

Configuration

Session Profile (`BepInEx/config/synergy_profile.json`)

{
  "session_name": "Deep Exploration Team",
  "max_players": 4,
  "difficulty_scale": "adaptive",
  "resource_multiplier": 1.5,
  "oxygen_consumption": 0.85,
  "creature_spawn_divider": 1.5,
  "enable_pvp": false,
  "friendly_fire": false,
  "shared_blueprints": true,
  "ping_locations_shared": true,
  "time_of_day_sync": "host",
  "voice_chat_integration": "discord_rpc",
  "locale": "en_US",
  "api_integration": {
    "openai": {
      "enabled": false,
      "api_key_env": "OPENAI_API_KEY",
      "model": "gpt-4",
      "role": "narrator"
    },
    "claude": {
      "enabled": false,
      "api_key_env": "ANTHROPIC_API_KEY",
      "model": "claude-3-opus-20240229",
      "role": "lore_engine"
    }
  },
  "network": {
    "nat_traversal": true,
    "max_latency_ms": 250,
    "sync_interval_ms": 50,
    "inventory_hash_algorithm": "sha256"
  }
}

Key Configuration Fields:

difficulty_scale: "static", "adaptive", or "linear" - controls how game difficulty adjusts with player count
resource_multiplier: Float multiplier for harvestable resource nodes (1.0 = vanilla, 2.0 = double)
oxygen_consumption: Fraction of normal oxygen drain (0.5 = half drain, 1.0 = vanilla)
creature_spawn_divider: Reduces creature spawns (2.0 = half spawns)
time_of_day_sync: "host" (host controls time), "all" (synced vote), "independent" (client-specific)
api_key_env: Environment variable name containing API keys (never hardcode keys)

XML Configuration (`BepInEx/config/session_config.xml`)

<?xml version="1.0" encoding="utf-8"?>
<SynergyConfig>
  <Session>
    <DefaultPort>25565</DefaultPort>
    <EnableUPnP>true</EnableUPnP>
    <MaxConnectionAttempts>5</MaxConnectionAttempts>
    <ConnectionTimeoutSeconds>30</ConnectionTimeoutSeconds>
  </Session>
  <Synchronization>
    <InventoryHashInterval>1000</InventoryHashInterval>
    <CreatureStateInterval>200</CreatureStateInterval>
    <BaseStructureInterval>500</BaseStructureInterval>
  </Synchronization>
  <Logging>
    <Level>Info</Level>
    <EnableNetworkDebug>false</EnableNetworkDebug>
  </Logging>
</SynergyConfig>

In-Game Console Commands

Access the BepInEx console with F12 (default binding, configurable):

Session Management

# Start hosting a session
/start_server
# Output: Server created: session code = 9B2A-4C7D-E8F1

# Join existing session
/join_session 9B2A-4C7D-E8F1

# Check connection status
/synergy_status
# Output:
# Connected peers: 3/4
# State sync: 100% complete
# Inventory hash: 0xFA342B1E
# Avg latency: 45ms

# Leave session gracefully
/disconnect_session

Gameplay Scaling

# Temporarily adjust difficulty multiplier
/synergy_scale 1.5

# Reset to config defaults
/synergy_reset

# Force world seed sync (host only)
/seed_override 8251

AI Narrative Integration

# Trigger OpenAI narrative generation
/api_narrate "discovered alien artifact in lost river"

# Generate species biology log with Claude
/api_lore_generate "ghost leviathan juvenile"

# Show last 5 AI-generated journal entries
/api_journal_history 5

Debugging

# Enable verbose network logging
/debug_network true

# Dump current inventory Merkle tree
/debug_inventory_tree

# Force state resync
/force_resync

# Show desync detection results
/debug_conflicts

Plugin Development & Extension

BepInEx Plugin Structure

The mod uses BepInEx IL2CPP hooking. To extend functionality:

using BepInEx;
using BepInEx.IL2CPP;
using HarmonyLib;
using DeepSynergy.Core;

namespace DeepSynergy.CustomExtension
{
    [BepInPlugin(PluginGUID, PluginName, PluginVersion)]
    [BepInDependency("com.deepsynergy.core")]
    public class CustomExtensionPlugin : BasePlugin
    {
        public const string PluginGUID = "com.yourname.customextension";
        public const string PluginName = "Custom Deep Synergy Extension";
        public const string PluginVersion = "1.0.0";

        private Harmony _harmony;

        public override void Load()
        {
            _harmony = new Harmony(PluginGUID);
            _harmony.PatchAll();
            
            // Hook into session events
            SessionManager.OnPlayerJoined += OnPlayerJoinedHandler;
            SessionManager.OnInventorySynced += OnInventorySyncedHandler;
            
            Log.LogInfo($"{PluginName} loaded successfully");
        }

        private void OnPlayerJoinedHandler(string playerId)
        {
            Log.LogInfo($"Player joined: {playerId}");
            // Custom logic here
        }

        private void OnInventorySyncedHandler(InventorySyncData data)
        {
            Log.LogInfo($"Inventory synced - hash: {data.MerkleRootHash}");
        }
    }
}

Harmony Patch Example

using HarmonyLib;
using DeepSynergy.Core;

namespace DeepSynergy.CustomExtension
{
    [HarmonyPatch(typeof(Player), "ConsumeOxygen")]
    public static class OxygenConsumptionPatch
    {
        static void Prefix(ref float amount)
        {
            // Apply session multiplier from config
            float multiplier = SynergyConfig.Current.OxygenConsumption;
            amount *= multiplier;
            
            // Sync to other clients
            if (SessionManager.IsHost)
            {
                NetworkSync.BroadcastOxygenEvent(amount);
            }
        }
    }
}

Custom API Integration

using DeepSynergy.API;
using System.Threading.Tasks;

public class CustomNarrativeGenerator
{
    private readonly OpenAIClient _openai;
    
    public CustomNarrativeGenerator()
    {
        string apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY");
        _openai = new OpenAIClient(apiKey);
    }
    
    public async Task<string> GenerateBaseDescription(BaseStructure baseData)
    {
        string prompt = $@"Generate a brief narrative description for an underwater base:
- Location: {baseData.Biome}
- Depth: {baseData.DepthMeters}m
- Components: {string.Join(", ", baseData.Modules)}
- Players: {baseData.PlayerCount}
Keep it under 100 words, immersive tone.";

        var response = await _openai.GenerateCompletion(prompt, maxTokens: 150);
        return response.Text;
    }
}

Common Usage Patterns

Two-Player Resource Gathering Session

{
  "session_name": "Resource Run",
  "max_players": 2,
  "difficulty_scale": "static",
  "resource_multiplier": 1.3,
  "oxygen_consumption": 0.9,
  "creature_spawn_divider": 1.2,
  "shared_blueprints": true,
  "time_of_day_sync": "host"
}

Console workflow:

# Player 1 (Host)
/start_server
# Share code 4A7B-9C2D-E5F3 with Player 2

# Player 2 (Client)
/join_session 4A7B-9C2D-E5F3

# Both players check sync
/synergy_status

Four-Player Base Building

{
  "session_name": "Mega Base Construction",
  "max_players": 4,
  "difficulty_scale": "adaptive",
  "resource_multiplier": 2.0,
  "oxygen_consumption": 0.7,
  "creature_spawn_divider": 2.0,
  "shared_blueprints": true,
  "ping_locations_shared": true,
  "time_of_day_sync": "all"
}

AI-Enhanced Exploration

{
  "session_name": "Lore Expedition",
  "max_players": 2,
  "api_integration": {
    "openai": {
      "enabled": true,
      "api_key_env": "OPENAI_API_KEY",
      "model": "gpt-4",
      "role": "narrator"
    },
    "claude": {
      "enabled": true,
      "api_key_env": "ANTHROPIC_API_KEY",
      "model": "claude-3-opus-20240229",
      "role": "lore_engine"
    }
  }
}

Generate narratives during gameplay:

/api_narrate "entering the blood kelp zone at 300m depth"
# Output: "The crimson fronds pulse with bioluminescent life as the team descends..."

/api_lore_generate "crabsquid behavior patterns"
# Output: "Species: Crabsquid (Elektrus Crustacea)..."

Troubleshooting

Issue: "Session code invalid or expired"

Cause: NAT traversal failed or host disconnected

Solution:

# Check NAT configuration
/debug_network true
# Look for "NAT type: Symmetric" in logs (problematic)

# Enable UPnP in session_config.xml
<EnableUPnP>true</EnableUPnP>

# Alternative: Port forward 25565 on router

Issue: "Inventory desync detected"

Cause: High latency or packet loss causing Merkle tree mismatch

Solution:

# Check current sync status
/debug_conflicts

# Force full resync
/force_resync

# Adjust sync interval in config
"sync_interval_ms": 100  # Increase from 50ms

Issue: "BepInEx mod not loading"

Cause: IL2CPP hook failure or incorrect installation

Solution:

Check BepInEx/LogOutput.log for errors
Verify BepInEx version is 6.0.x or higher
Ensure all .dll files are in BepInEx/plugins/
Delete BepInEx/cache/ and restart game

Issue: "OpenAI/Claude API calls failing"

Cause: Missing or invalid API keys

Solution:

# Verify environment variable is set
# Windows PowerShell
echo $env:OPENAI_API_KEY

# Linux/macOS
echo $OPENAI_API_KEY

# Set if missing (do NOT commit to code)
# Windows
setx OPENAI_API_KEY "your-key-here"

# Linux/macOS
export OPENAI_API_KEY="your-key-here"

Check config references correct env var:

"api_integration": {
  "openai": {
    "api_key_env": "OPENAI_API_KEY"  // Must match env var name
  }
}

Issue: "High latency/lag in multiplayer"

Cause: Network congestion or inefficient sync intervals

Solution:

# Check current latency
/synergy_status
# If avg latency > 150ms, adjust config

# Increase sync intervals in session_config.xml
<InventoryHashInterval>2000</InventoryHashInterval>  # From 1000
<CreatureStateInterval>400</CreatureStateInterval>   # From 200

# Reduce max players
"max_players": 2  # From 4

Issue: "Creatures not syncing properly"

Cause: Creature AI state lattice desync

Solution:

# Enable creature debug logging
/debug_network true

# Check creature sync interval
<CreatureStateInterval>200</CreatureStateInterval>

# Force creature state resync (host only)
/force_resync creatures

Advanced Configuration

Custom Biome Multipliers

Edit synergy_profile.json to add biome-specific resource scaling:

{
  "biome_overrides": {
    "safe_shallows": {
      "resource_multiplier": 1.0,
      "creature_spawn_divider": 1.0
    },
    "kelp_forest": {
      "resource_multiplier": 1.2,
      "creature_spawn_divider": 1.3
    },
    "blood_kelp_zone": {
      "resource_multiplier": 1.5,
      "creature_spawn_divider": 2.0
    },
    "lost_river": {
      "resource_multiplier": 2.0,
      "creature_spawn_divider": 2.5
    }
  }
}

Session Persistence

Enable session save/load:

{
  "session_persistence": {
    "enabled": true,
    "autosave_interval_minutes": 10,
    "save_directory": "BepInEx/saves/",
    "compress_saves": true
  }
}

Load saved session:

/load_session "Deep_Exploration_2026-05-14"

Localization Customization

Add custom translations in BepInEx/config/localizations/custom_en.json:

{
  "ui.session.created": "Session established: {0}",
  "ui.player.joined": "{0} has entered the abyss",
  "ui.inventory.synced": "Inventory synchronized",
  "console.help.start_server": "Create a new multiplayer session"
}

Reference in code:

string message = LocalizationManager.Get("ui.player.joined", playerName);

Performance Optimization

Reduce Bandwidth Usage

{
  "network": {
    "compression": "lz4",
    "delta_encoding": true,
    "sync_radius_meters": 500,  // Only sync entities within 500m
    "inventory_batch_updates": true
  }
}

Optimize for Low-End Systems

{
  "performance": {
    "reduce_sync_precision": true,  // Reduce float precision for position sync
    "skip_inactive_entities": true,  // Don't sync entities outside render distance
    "lazy_merkle_updates": true      // Update inventory tree only on change
  }
}

Security Considerations

Never hardcode API keys - always use environment variables
Session codes are single-use - regenerate for each session
Inventory Merkle trees prevent duping - tampering detected automatically
Host migration is automatic - session survives host disconnection
No executable code transmission - only JSON state data synchronized

FAQ

What does the subnautica-2-deep-synergy-coop-mod skill do?

BepInEx-based cooperative multiplayer mod for Subnautica 2 with synchronized sessions, shared inventory, and AI-enhanced narrative generation

How do I install subnautica-2-deep-synergy-coop-mod?

Run npx skills add https://github.com/reason-machines/devtools-skills --skill subnautica-2-deep-synergy-coop-mod in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/subnautica-2-deep-synergy-coop-mod/ (personal) or .claude/skills/subnautica-2-deep-synergy-coop-mod/ (project).

Which AI agents can use subnautica-2-deep-synergy-coop-mod?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is subnautica-2-deep-synergy-coop-mod safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains subnautica-2-deep-synergy-coop-mod?

It is published by reason-machines in reason-machines/devtools-skills. It has 227 recorded installs.

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subnautica-2-deep-synergy-coop-mod

Install

Install

Describe the task

Review the result

SKILL.md

Subnautica 2 Deep Synergy Coop Mod

Overview

Installation

Prerequisites

Directory Structure

First Launch

Configuration

Session Profile (BepInEx/config/synergy_profile.json)

XML Configuration (BepInEx/config/session_config.xml)

In-Game Console Commands

Session Management

Gameplay Scaling

AI Narrative Integration

Debugging

Plugin Development & Extension

BepInEx Plugin Structure

Harmony Patch Example

Custom API Integration

Common Usage Patterns

Two-Player Resource Gathering Session

Four-Player Base Building

AI-Enhanced Exploration

Troubleshooting

Issue: "Session code invalid or expired"

Issue: "Inventory desync detected"

Issue: "BepInEx mod not loading"

Issue: "OpenAI/Claude API calls failing"

Issue: "High latency/lag in multiplayer"

Issue: "Creatures not syncing properly"

Advanced Configuration

Custom Biome Multipliers

Session Persistence

Localization Customization

Performance Optimization

Reduce Bandwidth Usage

Optimize for Low-End Systems

Security Considerations

FAQ

More from reason-machines/devtools-skills

Popular other skills

Session Profile (`BepInEx/config/synergy_profile.json`)

XML Configuration (`BepInEx/config/session_config.xml`)