AnkleBreaker Unity MCP

AnkleBreaker Unity MCP

Build worlds. Coordinate agents. See every action. Connect your AI assistants to scene authoring, running games, multiplayer scenarios, tests, builds and profiling through Model Context Protocol. Built by AnkleBreaker Studio for workflows that span more than one editor and one assistant.

Get started · Watch the demos · Measured improvements · Multiple projects · Tool catalog · Changelog

Counts reflect the checked-in definitions; optional tools require their corresponding Unity packages. The advanced proxy also discovers routes advertised by newer plugins.

Watch it build a playable prototype

Neon brick breaker: scene construction, materials, gameplay scripts and visual iteration, with the assistant and Unity visible together.

▶ Open video · 25 seconds · Download MP4 · Village and castle demos

Recorded, accelerated excerpts. The silent videos export the same recordings as the GIFs; their duration is not a build-time benchmark. Media details and example prompts.

Built for demanding Unity workflows

The combination is the strength: routing, scheduling, multiplayer controls and observable results in one workflow. See choosing a Unity integration for a sourced comparison.

Why choose AnkleBreaker? Each agent keeps its project identity, each editor has its own queue, and supported actions leave a history you can inspect and undo. Advanced tools extend that workflow into multiplayer iteration, Unity Hub and project-specific integrations. Those behaviors have dedicated regression checks and real-editor evidence, not just a feature list.

Get started

Install from source: the commands below install main in both repositories, including the improvements documented here. Published npm packages and version tags may lag behind main.

1. Add the Unity plugin

In Unity, open Window → Package Manager → Add package from git URL:

https://github.com/AnkleBreaker-Studio/unity-mcp-plugin.git#main

The MCP status dropdown appears automatically in Unity's main toolbar. Open the Dashboard from it, Window → AB Unity MCP, or Tools → AnkleBreaker → Unity MCP. Verify the bridge is running there. If you previously hid the indicator, choose Show Toolbar Status. Toolbar and menu access.

2. Install the server

Use Node.js 18 or newer; a maintained Node.js LTS is recommended.

git clone --branch main https://github.com/AnkleBreaker-Studio/unity-mcp-server.git
cd unity-mcp-server
npm ci

3. Connect your assistant

For clients that accept an mcpServers JSON configuration:

{
  "mcpServers": {
    "unity": {
      "command": "node",
      "args": ["C:/path/to/unity-mcp-server/src/index.js"]
    }
  }
}

Use the absolute path to your checkout. On macOS and Linux, use its Unix path. Clients with another configuration format need the same command and arguments. Restart or reconnect the client's MCP session after editing the configuration.

Editor discovery is automatic. Unity Hub is only needed for Hub commands; set UNITY_HUB_PATH if it is installed elsewhere. See all configuration options.

4. Try a complete workflow

List my running Unity projects. Select my prototype, inspect its scene and compilation errors, create a platform, then capture the scene so I can review it.

Find the multiplayer tools. List my MPPM scenarios and the players configured in the selected project.

Inspect the scene's memory use and largest objects, then show me the actions performed by each agent.

From environments to playable levels

A village, built and refined in Unity

Terrain, houses, materials, trees, fences and paths: the assistant constructs a scene and inspects the result as it goes.

▶ Open video · 25 seconds · Download MP4

A castle you can walk through

Multi-room construction, lighting adjustment and a first-person walkthrough in the recorded project.

▶ Open video · 18 seconds · Download MP4

All demonstrations, prompts and media formats →

Multiple projects, multiple agents

Keep an agent on your game, another on a package test project, and use the multiplayer tools to inspect Host/Client scenarios. Project routing and per-agent scheduling are separate responsibilities, so requests retain their destination while waiting for Unity.

1. Call unity_list_instances and identify the project by name and path.
2. Call unity_select_instance with projectName or a discovered port.
3. Include that port on editor calls when coordinating simultaneous tasks.
4. Discover again after an editor restart: ports are dynamic.

Discovery checks the live Unity identity before adopting a port, including registry and default-port fallbacks. Named selection keeps that identity through verification, and stale discovery cannot overwrite a newer project choice. Identity, concurrent selection and compatibility.

{"name":"unity_editor_state","arguments":{"port":7891}}

7891 is an example; use the port returned by discovery. MCP callers can pass _meta.agentId (or the compatible _meta.agent_id) to keep agent selections and queue attribution separate. Each stdio process has its own default identity.

Within an editor, the plugin serializes writes and batches up to five reads per update. Different editor processes have independent queues. Simultaneous agents can still make conflicting edits to the same object, so assign clear ownership for shared scene work.

Explore the editor

Discover advanced capabilities with unity_list_advanced_tools. Filter by category or search, retrieve the schema for the tool you need, then call it through unity_advanced_tool. Full category guide and examples →

Workflows to try next

These are example prompts, not automatic scripts. Select the intended project first and let the assistant discover the current tool schemas and available packages.

Measured improvements

Measurements use separate before/after fixtures and historical baselines on Unity 6000.6.2f1 / Windows. Each linked report states its scope. These results do not measure whole-editor FPS or establish a speed ranking against other MCP products.

Compatibility and validation

The plugin declares Unity 2021.3.18f1+ support. Server and plugin versions advance independently and do not need matching version numbers. Current live validation uses Unity 6000.6.2f1 on Windows; minimum-version C# compilation also passes. Actual older-editor execution is deferred.

263 server tests pass across eight CI configurations (Node 18/20/22/24 on Windows/Linux), and the plugin's registry check covers 338 routes. Real-editor workflows include mixed released/current components, two editors, MPPM Host/Client, ParrelSync and actual script reloads. These checks have different recorded source checkpoints; the delivery summary identifies them and the remaining coverage limits.