# Build Gtk

Builds node-based Editor tools with Unity Graph Toolkit (GTK) on Unity 6.6+: graphs...

- Repository: https://github.com/Unity-Technologies/skills (1197 stars)
- Category: Engineering
- License: see repository
- Last updated: 2026-10-30
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add Unity-Technologies/skills --skill build-gtk -g -a claude-code -y`
Codex: `npx skills add Unity-Technologies/skills --skill build-gtk -g -a codex -y`
Cursor: `npx skills add Unity-Technologies/skills --skill build-gtk -g -a cursor -y`
Gemini CLI: `npx skills add Unity-Technologies/skills --skill build-gtk -g -a gemini-cli -y`

## Description

Builds node-based Editor tools with Unity Graph Toolkit (GTK) on Unity 6.6+: graphs, nodes, ports and validation, State Machine API tools on 6.7+, and runtime assets via a scripted importer. Use for custom graph, node or state machine editors, or migrating a GraphView tool. Not for Shader Graph, VFX Graph or Animator Controllers.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# Unity Graph Toolkit (GTK)

Build Editor graph tools and state machine tools on Unity's Graph Toolkit module, using only its
public API in the `Unity.GraphToolkit.Editor` namespace.

## Important

- Create a restore point you can roll back to if your changes fail.
- Do only what's asked. Don't change unrelated assets or files. Avoid long explanations.
- Before you go forward with a workflow or diagnosis, open and read the reference file(s) named in
  that workflow and the [Topic map](#topic-map) page(s) that cover the thing you intend to do. Name
  the file(s) you read in your response. This is because your training knowledge about Unity might be
  out of date, incorrect, or for the wrong Unity version, and Graph Toolkit changed between 6000.4,
  6000.6 and 6000.7.

## References

Read these as needed. Paths are relative to this skill's folder.

- `references/graph-api.md`, the Graph API surface: Graph, Node, port and option builders, context
  and block nodes, subgraphs, variables, validation, toolbar and context menus. Read before writing any
  graph-tool code.
- `references/state-machine-api.md`, the State Machine API (Unity 6.7+): StateMachine, State,
  Condition, transitions and rules, self transitions, custom views. Read whenever states, transitions
  or conditions are involved.
- `references/runtime-and-visualization.md`, compiling a graph or state machine into a runtime asset
  with a ScriptedImporter, and showing live execution in the graph editor. Read when the user wants the
  authored data used in the game or debugged at runtime.
- `references/pitfalls.md`, the mistakes that survive compilation. Read before handing off, and
  whenever the user reports a compile error, an empty Add menu, a missing node, or an exception.

## Step 1: Check the Editor version and pick the API

The rest: https://github.com/Unity-Technologies/skills/blob/HEAD/skills/build-gtk/SKILL.md