CET MCP — Cyberpunk 2077 AI Bridge

MCP server that connects Claude Code to Cyber Engine Tweaks (CET) in Cyberpunk 2077. Execute Lua code, query game state, manipulate TweakDB, manage inventory, and observe game events — all from your terminal while the game is running.

How it works

Claude Code → stdio/JSON-RPC → MCP Server → TCP (RedSocket) → CET Bridge Mod → Game Engine

The MCP server runs as a Claude Code subprocess. It opens a TCP server on localhost:27010. The CET Bridge Mod (Lua) connects to it via RedSocket and executes commands in the game's Lua VM. Falls back to file-based IPC automatically if RedSocket is not installed or if the TCP port is already in use (multiple sessions supported).

Pairs with WolvenKit MCP for a complete AI-assisted modding pipeline.

Requirements

• Node.js >= 18
• Cyberpunk 2077 with Cyber Engine Tweaks >= 1.32
• RED4ext >= 1.25
• RedSocket (recommended — enables TCP transport, ~1ms latency vs ~16-33ms with file IPC)

Setup

# 1. Clone and build
git clone https://github.com/y4rd13/cyber-engine-tweak-mcp.git
cd cyber-engine-tweak-mcp
npm install
npm run build

# 2. Copy CET mod to game directory
cp -r cet-mod/CETBridge "/path/to/Cyberpunk 2077/bin/x64/plugins/cyber_engine_tweaks/mods/CETBridge"

# 3. Add to Claude Code globally
claude mcp add cet-bridge -s user \
  -e "CET_BRIDGE_DIR=/path/to/cyber_engine_tweaks/mods/CETBridge" \
  -e "CET_TRANSPORT=tcp" \
  -- node /path/to/cyber-engine-tweak-mcp/build/index.js

Tools (37)

Execution

Tool	Description
execute_lua	Run Lua code in the CET console
evaluate_expression	Evaluate a Lua expression and return the result
batch_execute	Execute multiple Lua statements in one round-trip

Game State

Tool	Description
get_player_info	Player level, health, street cred, position
get_game_state	In-game time, scene tier, weather, zone type
add_item	Add item to inventory by TweakDB ID
teleport	Teleport player to world coordinates
set_time	Change in-game time of day
set_weather	Change weather (Sunny, Rain, Fog, Sandstorm, etc.)

Inventory

Tool	Description
get_inventory	List player inventory with type filtering
remove_item	Remove items from inventory
get_equipped	Show currently equipped weapons, clothing, cyberware

Player

Tool	Description
set_stat	Modify player stats (Health, Armor, Level, etc.)
apply_status_effect	Apply buffs/debuffs to the player
remove_status_effect	Remove status effects
get_active_effects	List all active status effects on the player
toggle_god_mode	Toggle invulnerability on/off
set_level	Set player level and/or street cred directly
get_appearance_info	Get player's current visual appearance
get_vehicle_list	List all vehicles in the player's garage

World

Tool	Description
spawn_vehicle	Spawn a vehicle near the player
get_nearby_entities	Scan for nearby NPCs, vehicles, items
kill_nearby_npcs	Kill hostile (or all) NPCs in radius
show_notification	Show in-game UI notification
play_sound	Play a sound event in-game
get_scanner_info	Get info about the entity you're looking at

Quest

Tool	Description
get_quest_fact	Read a quest progression flag
set_quest_fact	Set a quest progression flag

TweakDB

Tool	Description
get_tweakdb_value	Read a TweakDB flat or record
set_tweakdb_value	Write a TweakDB flat value
search_tweakdb	Search TweakDB records by pattern
dump_type	Introspect a game RTTI type (methods, properties)

Observation

Tool	Description
observe_events	Subscribe to game events via CET Observe
get_observations	Read buffered event observations

Dev Tools

Tool	Description
get_connection_status	Check bridge connectivity and transport type
read_log	Read CET scripting.log
list_mods	List installed CET mods

Configuration

Variable	Default	Description
CET_BRIDGE_DIR	(see .mcp.json)	Path to CETBridge mod directory
CET_TRANSPORT	tcp	Transport: tcp (RedSocket) or file (fallback)
CET_TCP_PORT	27010	TCP server port

Multi-Session Support

Multiple Claude Code sessions can use cet-bridge simultaneously:

• First session: binds TCP port 27010 (fast, ~1ms)
• Additional sessions: automatically fall back to file-based IPC (~16-33ms)
• No session crashes — the fallback is seamless

Architecture

See docs/architecture.md for detailed diagrams.

Component	Language	Role
MCP Server	TypeScript	stdio transport for Claude Code, TCP server for game bridge
CET Bridge Mod	Lua	Runs in-game, dispatches commands to CET Lua VM

Development

npm run build    # Compile TypeScript
npm run dev      # Watch mode
npm run inspect  # Test with MCP Inspector

After changing Lua files, copy them to the game directory:

cp cet-mod/CETBridge/*.lua "/path/to/cyber_engine_tweaks/mods/CETBridge/"

Safety

• TCP binds to localhost only — no network exposure
• All user code runs in pcall() — errors are caught, never crash the game
• This is a development tool — not intended for multiplayer or production use
• Infinite loops in executed Lua will freeze the game (no mitigation possible without native code)

License

MIT