PCGEx | Assistant

AI agent integration for the PCGEx ecosystem
The PCGEx knowledge base, the live editor, PCGEx nodes in your graphs and PCGEx data as JSON, exposed to any MCP client through the engine's Model Context Protocol server.

Documentation • Discord

The plugin registers a PCGEx toolset with Unreal's experimental Toolset Registry and ships an offline, source-verified knowledge base covering every documented node of PCGEx and its sibling plugins (Valency, Cluster Sketch, ZoneGraph, Kweave): purpose, mechanism, exact pin contracts, settings semantics and known traps, matched to the installed plugin versions. Any MCP client (Claude Code, Cursor, VS Code, and others) connected to the engine's Model Context Protocol server can then search that knowledge base, inspect the installed PCGEx plugins, place PCGEx nodes in a graph, author PCGEx data as JSON, and ground its answers in what the nodes actually do instead of guessing.

Important

Authoring PCGEx data as JSON needs the PCGEx Toolset in the project. The Assistant reaches it by reflection and never links it: without it the knowledge, introspection and graph tools work and the skill reports authoring as unavailable. From PCGEx 0.80 the FAB packages carry the toolset (PCGEx Pro carries the Valency and Cluster Sketch toolsets as well); from source it is its own repository.

Requirements

• Unreal Engine 5.8.
• PCGExtendedToolkit.
• The engine's experimental Toolset Registry plugin, enabled automatically as a dependency, and its Model Context Protocol plugin for clients to connect.

Editor-only: nothing ships in cooked builds. The plugin is off by default; enable it in Edit > Plugins.

Getting it

From FAB: install PCGEx Assistant to your 5.8 engine next to PCGEx 0.80 or later, which ships the toolset inside its package.

From source: the knowledge base is the PCGExKnowledge repository, pinned as the Knowledge/ submodule. Clone with it, or the plugin loads and raises Knowledge bundle unavailable:

git clone --recurse-submodules https://github.com/PCGEx/PCGExAssistant Plugins/PCGExAssistant

As a submodule of your project, then fetch the nested one:

git submodule add https://github.com/PCGEx/PCGExAssistant Plugins/PCGExAssistant
git submodule update --init --recursive

The toolkit's 5.8 branch pairs with this plugin; the Assistant itself tracks main. The full checklist, with the toolset and its Pro siblings, is in the documentation.

Setup

1. Enable the PCGEx Assistant and Model Context Protocol plugins (both require an editor restart).
2. In Editor Preferences > Plugins > Model Context Protocol: enable Auto Start Server. For the most direct experience, disable Enable Tool Search so PCGEx tools appear as first-class tools in your client.
3. Point your MCP client at the editor, either by letting the engine write the client configuration for you, or manually:

{ "mcpServers": { "unreal": { "type": "http", "url": "http://127.0.0.1:8000/mcp" } } }

For Claude Code, save this as .mcp.json at your project root, or run claude mcp add --transport http unreal http://127.0.0.1:8000/mcp. With the editor running, ask a PCGEx question and watch it answer from the knowledge base.

Tools

The toolset ships with a skill the client fetches: static grounding rules, plus an authoring section composed at every fetch from what the editor binds right now (hosts, actions and per-domain guides from the installed toolsets).

Knowledge, from the offline bundle:

Tool	What it does
SearchKnowledge	Free-text search across every documented node and concept page of the installed PCGEx plugins.
GetNode	The full knowledge entry for one node: purpose, mechanism, pin contract, settings semantics, traps, documentation link.
GetConcept	A concept documentation page (clusters, filters, staging, tensors, ...) with its outline, link and, when the bundle carries it, its full prose.

Introspection, from the running editor:

Tool	What it does
GetInstalledPCGExPlugins	Names and versions of the PCGEx-family plugins in the project.
ListRegisteredNodeTypes	Live reflection over the node types actually registered in this editor session.
GetNodeSchema	The live, writable schema of a node class: pins as the installed version declares them and the JSON shape its params accept, annotated from the knowledge base.

Graphs, what the engine's PCG toolset cannot do for PCGEx nodes:

Tool	What it does
CreateNode	Adds a node of any settings class to a PCG graph. The engine's own PCG toolset only knows nodes from the PCG package; this covers PCGEx and everything else.
AddSubnodes	Creates a set of provider nodes (filters, heuristics, tensors, samplers) and wires them into a target node in one undoable operation.

Editing an existing node (params, connections, comments, removal) is left to the engine's PCG toolset, whose tools work on any node once it exists.

Authoring, served by PCGEx Toolset through reflection:

Tool	What it does
ListFormats	Which assets and nodes are bound, which document formats exist, which actions are registered.
DescribeFormat	The JSON Schema of a format, of an action's params, of a bound class's whole document, or of any struct by path.
DescribeTarget	What one existing instance offers: resolved properties, defaults, choices and locks.
ExportJson	A bound asset or node as a sparse document that re-imports unchanged.
ImportJson	Applies a document to a bound target as one undoable transaction; nothing applies unless the whole document decodes.
CreateAsset	Creates an asset of a class with a factory, unsaved, ready for ImportJson.
SaveAsset	Writes an asset's package to disk.
Undo	Reverts the editor's last transaction, an import being one.
RunAction	Runs a registered action on a target, undoable (align choices, build a sketch, rebuild a Bonding Rules kit, ...).
Open	Brings a target in front of the user: asset editor, graph node, level actor, or a domain's own mode.

Every target is an asset's object path or <graph path>:<node>, and also accepts @focused (what the user is looking at) and @selected (the level or Content Browser selection).

Knowledge data

The knowledge base is rendered from the same verified card store that produces the PCGEx documentation, and is also published as raw JSON at PCGEx/PCGExKnowledge for anyone who wants to build their own tooling on it.

Links

• Documentation: https://pcgex.gitbook.io/pcgex/ai
• PCGEx: https://pcgex.gitbook.io/pcgex/
• Discord: https://discord.gg/mde2vC5gbE