Extensions

Extensions are optional NuGet packages that teach Godot MCP about more parts of Godot and about popular Godot addons. Install only the ones your project needs. This page lists them, explains how they work, and shows the three ways to install one. Descriptions and examples for each extension are on the site's Godot extensions page.

How extensions work#

Each extension is an RQL module. It adds no MCP tools of its own. Instead, it extends the core rql-query, rql-mutate and rql-schema tools with new sources, validated properties and calls, and adds a guide to the agent's godot-rql skill. Your agent's tool list stays the same size, and the agent learns the new area through rql-schema:

rql-schema "Particles"

The packages contain C# source and build settings, compiled against your project's own GodotSharp. Each extension has its own version and release.

Available extensions#

Every extension also needs a core addon that has the RQL tools (any release after 0.28.0).

Install with godot-cli#

godot-cli install-extension com.IvanMurzak.Godot.MCP.CSG ./MyGodotProject
godot-cli build ./MyGodotProject

install-extension looks the id up in the extension catalog, by package id first and then by name, case-insensitive (so "CSG Tools" also works). It then adds or updates a <PackageReference> in your project's .csproj:

• not referenced yet: the reference is added;
• an older version is referenced: it is updated;
• already up to date: nothing changes.

Without --version, the reference floats to the latest stable release on NuGet (Version="*"). Use --version <x.y.z> to request an exact version. After installing, build the project so Godot restores and compiles the package; Godot has no automatic restore step.

Install from the dock#

The Extensions section of the AI Game Developer dock lists the same catalog with Install and Update buttons. It edits the .csproj the same way as the CLI. Rebuild afterwards. If the dock says no .csproj was found, the addon is not inside a Godot C# project.

Install from the AI Game Dev app#

For Godot projects, the AI Game Dev app shows an Extensions button in the sidebar that opens the same catalog and installs through the same code as godot-cli. Its slash command /install-extension does the same from the app's chat: without arguments it lists the catalog, with an id it installs into the current project. Engine extensions are not the same as the app's own packages.

The extension catalog#

The list of extensions lives in addons/godot_mcp/extensions.catalog.json, shipped with the addon. The dock, godot-cli and the app all read this one file. The dock reads it from your compiled project, which is why your .csproj must embed it:

<ItemGroup>
  <EmbeddedResource Include="addons/godot_mcp/extensions.catalog.json" LogicalName="Godot-MCP.extensions.catalog.json" />
</ItemGroup>

godot-cli install-plugin and the app add this line for you. If you installed by hand and the Extensions list is empty, this line is missing; add it and rebuild. See Installation.

Using an extension#

After the build, just ask. For example, with CSG Tools installed:

• "Build a CSG combiner with a 3x3x3 box and subtract a sphere of radius 1.8 from it."
• "List every CSG shape in the scene with its operation and size."

The agent creates the nodes with rql-mutate (one undoable step per call) and checks the result with rql-query. Invalid values, such as a negative radius, fail the whole change and leave the scene untouched.

Write your own extension#

The Godot-MCP repository contains an extension template (templates/extension/) and a monorepo guide for building, testing and releasing modules. For one-off project tools, plain custom tools are simpler.