CheatEngine.Mcp

CheatEngine.Mcp connects a local AI client to Cheat Engine 7.7 x64 through the Model Context Protocol (MCP). It combines a plugin loaded by Cheat Engine with a standalone stdio gateway. One gateway can discover several Cheat Engine processes and route each request to the instance you choose.

Using the current source? Build the distribution from this checkout. Assets on the releases page may target an earlier version or tool contract. Keep the plugin folder and gateway executable from the same build.

How it works

AI client --stdio--> CheatEngine.Mcp.Gateway.exe
                         |
                         +-- authenticated loopback HTTP --> plugin in Cheat Engine A
                         +-- authenticated loopback HTTP --> plugin in Cheat Engine B

Each enabled plugin starts a backend on 127.0.0.1 with an automatically assigned port and a fresh access token. It publishes a per-activation discovery record for the current Windows user. The gateway verifies the backend's identity and routes calls by the explicit instanceId returned by instance_list. It does not start Cheat Engine, select a process, or choose an instance for you. Documents and prompts remain available through the gateway even when Cheat Engine is closed.

The default setup needs no MCP settings file, fixed port, URL, API key, or second gateway per Cheat Engine process. Run the gateway and Cheat Engine under the same Windows user account.

Install and connect | First use | Multiple instances | Configuration | Troubleshooting | Build from source | Projects

Install and connect

1. Get the deployment files

From the repository root, build the current source distribution with .NET SDK 10.0.401, PowerShell 7, and the Windows C++ build tools required by Native AOT:

pwsh -NoProfile -File eng/Publish.ps1 -Configuration Release

The result is in artifacts/dist/release/:

Item	Purpose
CheatEngine.Mcp/	Complete plugin folder, including CheatEngine.Mcp.Plugin.dll, dependencies, the native Lua bridge, and default settings.
CheatEngine.Mcp.Gateway.exe	Standalone Windows x64 MCP server launched by your AI client.
LICENSE and THIRD-PARTY-NOTICES.md	License and dependency notices for the distribution.

Copy these items together to a stable location, for example C:\Tools\CheatEngine.Mcp. Keep the plugin folder intact and the DLL name unchanged. A normal solution build creates development outputs; eng/Publish.ps1 creates the deployable layout and smoke-tests the gateway. See Build from source for the full development commands.

2. Prepare Cheat Engine's .NET host

Use Cheat Engine 7.7 x64. The plugin runs inside Cheat Engine and requires the x64 .NET 10, ASP.NET Core 10, and Windows Desktop 10 runtimes. Check them with dotnet --list-runtimes; the output must include Microsoft.NETCore.App, Microsoft.AspNetCore.App, and Microsoft.WindowsDesktop.App at version 10.0.x. The gateway executable is self-contained and does not use Cheat Engine's runtime configuration.

Cheat Engine's ce.runtimeconfig.json, beside its executable, must select .NET 10 and all three frameworks. Close Cheat Engine and back up that file before changing it. Preserve unrelated settings; a typical runtimeOptions section is:

{
  "runtimeOptions": {
    "tfm": "net10.0",
    "rollForward": "LatestMinor",
    "frameworks": [
      { "name": "Microsoft.NETCore.App", "version": "10.0.0" },
      { "name": "Microsoft.WindowsDesktop.App", "version": "10.0.0" },
      { "name": "Microsoft.AspNetCore.App", "version": "10.0.0" }
    ]
  }
}

Restart Cheat Engine after changing this file. Installing .NET 10 alone does not change a host configuration that selects another major version.

3. Enable the plugin

In Cheat Engine, open Edit > Settings > Plugins, add CheatEngine.Mcp.Plugin.dll from the deployed CheatEngine.Mcp folder, and enable it. The menu bar shows MCP: Enabled after the backend starts and its instance is published. Click the indicator for its instance name, listening address, and log location. Enabling the plugin does not attach Cheat Engine to a target process.

Enable the plugin separately in every Cheat Engine process you want to use. Leave the port at its default 0 so each process gets a free port.

4. Connect an AI client

Register one local stdio server whose command is the absolute path to CheatEngine.Mcp.Gateway.exe. For Codex, for example:

codex mcp add cheatengine -- "C:\Tools\CheatEngine.Mcp\CheatEngine.Mcp.Gateway.exe"
codex mcp list

For a client that uses an mcpServers JSON object:

{
  "mcpServers": {
    "cheatengine": {
      "command": "C:/Tools/CheatEngine.Mcp/CheatEngine.Mcp.Gateway.exe"
    }
  }
}

Use your client's equivalent command-based stdio setting if its format differs. Restart the client session after changing MCP registration. The client launches the gateway; double-clicking the executable does not configure a client. A remote or browser-only client needs a Windows-local component capable of launching the gateway.

First use

Ask the client to list Cheat Engine instances and inspect the selected target without changing memory. The intended call sequence is:

1. instance_list() returns verified plugin instances with instanceId, display name, Cheat Engine process ID, and plugin version.
2. Choose the intended instance and pass its exact instanceId to runtime_get_info and runtime_get_overview.
3. Check whether Cheat Engine has a target process open. The instance's processId is Cheat Engine's PID; the target has its own PID.
4. Select a target in Cheat Engine or request a process attach through the tools exposed by the live MCP schema. Confirm the target before reading or changing it.

The gateway-local instance_list needs no instanceId; every routed Cheat Engine tool does. There is no default or shared selected instance. An empty list means the gateway is connected but has not found a verified, enabled plugin. An ID changes when Cheat Engine restarts or the plugin is disabled and enabled again, so refresh instance_list before reusing one.

The server also offers the attach_and_orient guided prompt and the cheatengine://docs/getting-started resource. The tool map describes tool domains and capability requirements; the live MCP schema is authoritative for this build's exact names and arguments.

Multiple Cheat Engine instances

Open more than one Cheat Engine process and enable the plugin in each. One gateway discovers them all. Display names may repeat, so select by the returned instanceId and Cheat Engine PID.

The default name includes the Cheat Engine PID. To give each process a label, set MCP_INSTANCE_NAME before launching that process:

# First PowerShell window
$env:MCP_INSTANCE_NAME = 'game-a'
& 'C:\Program Files\Cheat Engine\cheatengine-x86_64.exe'

# Second PowerShell window
$env:MCP_INSTANCE_NAME = 'game-b'
& 'C:\Program Files\Cheat Engine\cheatengine-x86_64.exe'

These are display labels, not routing keys. An instance that stops is never replaced automatically by another one, even when their labels match. Keep Mcp:Port at 0; a fixed port must be unique across running instances. The connection guide explains discovery and stale IDs in more detail.

Configuration

The defaults work without creating a file. To change plugin settings, create %APPDATA%\CheatEngine.Mcp\appsettings.json and disable/re-enable the plugin. The plugin reads, in increasing priority: built-in defaults, its shipped appsettings.json, the user file, then the dedicated MCP_* environment overrides. It reads settings once per activation. Keep personal changes out of the shipped plugin folder because updates replace it.

A small optional user file looks like this:

{
  "Mcp": {
    "EnableUnsafeLua": false,
    "Files": {
      "AllowedRoots": ["C:\\CheatEngine\\Files"]
    }
  },
  "CheatEngineClient": {
    "AllowedTableRoots": ["C:\\CheatEngine\\Tables"]
  }
}

The four capability switches EnableUnsafeLua, EnableAutoAssembler, EnableTargetCodeExecution, and EnableKernelAccess are true by default. Set a switch to false to refuse its covered tools; runtime_get_info.gates reports the effective values. The file and table allowed-root lists are empty by default, so host-file writes and table load/save need explicit local folders. Capability switches refuse covered operations when disabled; they are not a sandbox for enabled operations. See the configuration reference and safety guide for every key and its effect.

Override	Used by	When to set it
MCP_INSTANCE_NAME	Plugin	Label one Cheat Engine process before launching it.
MCP_DATA_DIRECTORY	Plugin	Use a separate absolute directory for that process's user settings and logs.
MCP_INSTANCE_DIRECTORY	Plugin and gateway	Move the discovery registry; both sides must use the same absolute directory.
MCP_HOST, MCP_PORT	Plugin	Listener overrides; keep the loopback host and automatic port for normal use.
MCP_GATEWAY_CALL_TIMEOUT_SECONDS	Gateway	Set a routed-call timeout from 5 to 3600 seconds; default 45.

The gateway also accepts --instance-directory <absolute path> and --call-timeout-seconds <5..3600>. Arguments override its environment variables. If you move the registry, set MCP_INSTANCE_DIRECTORY for both the Cheat Engine and AI-client processes, or pass the matching directory to the gateway. Do not set it to an empty value. The default registry is %LOCALAPPDATA%\CheatEngine.Mcp\instances; its records contain access tokens and should stay private to the current user.

Tools, resources, and prompts

The tools cover process selection, value scans, typed memory, pointers, AOBs, disassembly, structures, address-list records, symbols, Mono/.NET inspection, debugger operations, and more. Some operations change Cheat Engine or target state; use the tool's live annotations, capability requirements, result, and cleanup guidance. The tool map is the searchable index.

The gateway serves project knowledge as cheatengine://docs/{slug} resources and guided prompts even without a running plugin. Examples include getting started, workflows, and errors and recovery. With an instance selected, live resources expose read-only snapshots under cheatengine://instances/{instanceId}/.... Clients with resource completion support can suggest recently verified instance IDs and instance-specific names.

Resources created by MCP, such as named scans, jobs, allocations, and patches, have an activation lifetime. Cheat Engine-owned state can persist after plugin disable. Before switching targets or ending a session, inspect runtime_list_resources and use the relevant release or restore tools. The session workflows describe cleanup and recovery.

Troubleshooting

Symptom	Check
The client shows no CheatEngine.Mcp tools	Confirm the gateway path and stdio registration, then inspect the client's MCP startup log. The gateway writes diagnostics to stderr.
instance_list is empty	Enable the plugin in Cheat Engine, confirm MCP: Enabled, use the same Windows account, and check that both sides use the same instance directory.
Cheat Engine cannot load the plugin	Check Cheat Engine 7.7 x64, the intact plugin folder, all three x64 .NET 10 runtimes, and ce.runtimeconfig.json.
One of several instances fails to start	Leave the port at 0, or give each process a distinct fixed port.
A previously working ID is unavailable	Refresh instance_list; restart and re-enable create new IDs. Do not redirect a failed call to another instance.
A tool reports no target	Select the intended target in Cheat Engine or attach through the chosen instance's process tools.
A setting prevents enable	Correct the named Mcp key or MCP_* variable, then re-enable the plugin.
A routed call times out	Inspect the instance and the target before repeating a mutation; its host effect may be unknown.

Plugin logs are written per Cheat Engine PID to %APPDATA%\CheatEngine.Mcp\CheatEngine.Mcp.<pid>.log, or to MCP_DATA_DIRECTORY when set. A load failure can occur before that log exists. See connection troubleshooting for status details and recovery steps.

Updating or removing the installation

To update, finish task cleanup, close Cheat Engine, stop the client's MCP connection, and replace the plugin folder and gateway together from one build. Restart Cheat Engine, enable the plugin, reconnect the client, and refresh instance_list. User settings survive because they are outside the distribution.

To remove the integration, release or manually restore task-owned state, disable the plugin, remove the gateway registration from the AI client, and then delete the deployment files. Disabling the plugin does not automatically undo every Cheat Engine-owned change.

Build from source

The repository pins .NET SDK 10.0.401 in global.json. PowerShell 7 and the Windows C++ build tools are needed for the Native AOT distribution. From the repository root:

dotnet restore CheatEngine.Mcp.slnx --locked-mode
dotnet build CheatEngine.Mcp.slnx --no-restore
dotnet test --solution CheatEngine.Mcp.slnx --no-restore --no-build --filter-not-trait Category=LiveQualification --filter-not-trait Category=NativeLua --fail-skips on
pwsh -NoProfile -File eng/Publish.ps1 -Configuration Release

Project dependencies are centrally versioned in Directory.Packages.props and locked per project. The plugin is framework-dependent inside Cheat Engine; the gateway is published as a self-contained Windows x64 Native AOT executable. The contributor guide covers CI checks, formatting, contract snapshots, and packaging.

Verification

The portable xUnit v3 suite uses Client doubles and real local HTTP/stdio hosts; it does not require Cheat Engine. The optional NativeLua suite needs a Lua 5.3 x64 DLL. The live two-instance qualification starts private Cheat Engine copies and requires an explicit maintainer-requested opt-in. See the test project guide and live qualification instructions. The publish script smoke-tests the gateway executable. A passing portable suite does not by itself qualify the native Cheat Engine host.

Repository layout

Project	Responsibility
Core	Shared composition, contracts, target state, and tool execution.
Tools	MCP tools grouped by Cheat Engine operation.
Resources	Embedded knowledge and live MCP resources.
Prompts	Guided workflows and server instructions.
Hosting	Backend hosting, discovery, and gateway routing.
Plugin	Cheat Engine entry point, activation lifecycle, Lua bridge, and logging.
Gateway	Stdio executable and composition root.
Tests	Contracts, offline integration, NativeLua, and live qualification.
LiveTarget	Disposable process used by live qualification.

Each linked README documents its own project's layout, dependencies, and contribution boundaries.

Migration, contributing, and license

This branch is a breaking redesign of CeMCP 1.x. The plugin is deployed as a folder rather than a single DLL, tool names and result contracts have changed, and instance routing is explicit. Consult the live tool schema when migrating scripts or prompts.

Use CheatEngine.Mcp only on software you own or are authorized to modify. Read SECURITY.md for the trust boundary and private vulnerability reporting, and CONTRIBUTING.md before submitting changes. The project is licensed under MIT; dependency licenses and attribution are in THIRD-PARTY-NOTICES.md.