Tool Groups

MCP for Unity ships 43 tools, but exposing all of them to the LLM at once balloons the prompt and dilutes routing decisions. So tools are sorted into groups, and only core is enabled by default.

The groups

Group	Default	Description
core	enabled	Essential scene, script, asset, and editor tools — always on.
animation	off	Animator control, AnimationClip creation.
ui	off	UI Toolkit — UXML, USS, UIDocument.
vfx	off	VFX Graph, shaders, procedural textures.
scripting_ext	off	ScriptableObject management.
testing	off	Test runner and async test jobs.
probuilder	off	ProBuilder 3D modeling. Requires com.unity.probuilder package.
profiling	off	Profiler session control, counters, memory snapshots, Frame Debugger.
docs	off	Unity API reflection and documentation lookup.

Enabling a group

Use the manage_tools meta-tool from your prompt:

Activate the vfx group so we can author shaders.

The assistant calls:

manage_tools(action="activate", group="vfx")

After activation, the group's tools appear in the next tool listing and are usable for the remainder of the session.

Listing what's available

manage_tools(action="list_groups")

Returns every group with its current activation state and tool names.

Deactivating

manage_tools(action="deactivate", group="vfx")

Useful when a group's tools are confusing the assistant — e.g., manage_shader and manage_material both apply to materials in different ways. Disabling the one you're not using keeps the assistant focused.

Other actions

• sync — refreshes visibility from the Unity Editor's per-tool toggle UI. Use after toggling tools in Window > MCP for Unity > Tools.
• reset — restores defaults (only core enabled).

Why this exists

Three reasons:

1. Prompt economy: each visible tool adds tokens to every assistant call. Hiding what you're not using is real money saved at scale.
2. Routing clarity: when the LLM picks between 43 tools versus 30, the wrong-tool rate drops measurably.
3. Package hygiene: tools in probuilder only work if com.unity.probuilder is installed; hiding them by default avoids confusing errors.

Server vs. session state

• The Unity Editor maintains a per-tool toggle UI (Window > MCP for Unity > Tools) that controls server-side visibility.
• The manage_tools meta-tool controls per-session visibility — different MCP sessions can see different groups even against the same server.

sync reconciles the two: it pulls the Editor's toggle states into the current session.

Related reference

• manage_tools — full tool reference
• tool_groups resource — discoverable group catalog