Agent skill

UMG Material MCP

by winyunq in winyunq/UnrealMotionGraphicsMCP

Creates, edits and compiles Unreal Engine 5.8 material assets as one HLSL Custom node through the UMG MCP bridge, instead of editing .uasset files directly.

MITAuto-check passedGame Development

Install UMG Material MCP

skills CLI
$ npx skills add winyunq/UnrealMotionGraphicsMCP --skill umg-material-mcp -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install winyunq/UnrealMotionGraphicsMCP umg-material-mcp --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/winyunq/UnrealMotionGraphicsMCP.git skills-src && mkdir -p .claude/skills && cp -r skills-src/Skills/umg-material-mcp .claude/skills/umg-material-mcp && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
umg-material-mcp
GitHub stars
210
Token cost
~913 tokens
SKILL.md length
352 words
Files
3 (incl. references)
Skills in repo
2
Repo updated
First seen
Licence
MIT

At a glance

Creates, edits and compiles Unreal Engine 5.8 material assets as one HLSL Custom node through the UMG MCP bridge, instead of editing .uasset files directly.

  • Works in 5 steps: Set or create the HLSL target with… → Read with hlsl_get. → Write with hlsl_set(hlsl?, parameters?,… → …
  • Creating a new UI material in Unreal Engine through the MCP bridge
  • SKILL.md covers Primary Workflow, Protocol Rules and Validation
  • Calls python

What it does

The skill keeps a material as a single HLSL program on a Custom node and works through five MCP tools: hlsl_set_target to create or select the material and its UI or non-UI type such as domain, blend mode and shading model, hlsl_get to read the current HLSL text, parameters and output contract as semantic state, hlsl_set to write HLSL, parameters or outputs as a union-only update that can add or change entries but never delete one, hlsl_delete to remove a named parameter or output with confirmation, and hlsl_compile to compile and surface diagnostics as the feedback loop.

It requires Unreal Editor to stay open with the UMG MCP bridge listening before any runtime call, and prefers small repair writes with hlsl_set over resetting the target when a compile fails. The output contract maps the Custom node's rgb and alpha outputs to the right material pins, for example emissive color for UI, PostProcess, LightFunction and unlit materials, and base color for a lit surface, with alpha going to opacity or an opacity mask when relevant. A reference file of demo cases gives concrete command examples and regression cases.

When your agent uses it

  • Creating a new UI material in Unreal Engine through the MCP bridge
  • Adding a custom parameter or output to an existing material's HLSL
  • Debugging a material compile error through the HLSL feedback loop

Example prompts

  • “Create a non-UI surface material and add an Intensity scalar parameter.”
  • “Add a Roughness output to this material's Custom node and recompile it.”
  • “My material failed to compile, read its current HLSL and fix the error.”

Requirements

  • Unreal Engine 5.8 with the UMG MCP bridge running

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

  1. Set or create the HLSL target with hlsl_set_target.
  2. Read with hlsl_get.
  3. Write with hlsl_set(hlsl?, parameters?, outputs?).
  4. Delete with hlsl_delete(names, confirm_delete=true, kind?).
  5. Compile with hlsl_compile.

What it can do on your machine

Read from SKILL.md and the folder at commit a0494ef. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • python

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

UMG Material MCP loads about 913 tokens when it runs, and up to ~1.6k if it reads all its reference files. Until then it costs about 90 tokens; SKILL.md has 352 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~90
When it runs · the whole SKILL.md, loaded when a task matches
~913
With references · SKILL.md plus every file in references/, read only if the agent opens them
~1.6k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from winyunq/UnrealMotionGraphicsMCP at commit a0494ef, republished under its MIT licence (© winyunq). 352 words, ~913 tokens.

Download SKILL.mdSave it as .claude/skills/umg-material-mcp/SKILL.md (or your agent's skills folder). This skill also uses 2 other files; get the full folder from GitHub.
name
umg-material-mcp
description
Use when Codex needs to create, inspect, edit, delete, or validate UE5.8 material assets through Unreal Motion Graphics MCP/FabUmgMcp HLSL material tools, especially one-HLSL Custom-node authoring, UI-default versus non-UI material type selection, union-only writes, semantic outputs, hlsl_delete recovery, or Material ToolMode protocol work.

UMG Material MCP

Use the Material HLSL MCP path for material authoring. Do not mutate .uasset files directly. Keep Unreal Editor open with the UMG MCP bridge listening before runtime tool calls.

For concrete command examples and regression cases, read demo-cases.md.

Primary Workflow

  1. Set or create the HLSL target with hlsl_set_target.

    • New targets default to UI material behavior.
    • For non-UI materials, pass type fields directly on hlsl_set_target: domain, blend_mode, shading_model, two_sided.
    • Prefer this over material_modify_type; that command is compatibility-only.
  2. Read with hlsl_get.

    • Treat the response as semantic state: HLSL text, parameter snapshot, and output_contract.
    • Do not request or reconstruct full material graphs unless the HLSL protocol cannot express the task.
  3. Write with hlsl_set(hlsl?, parameters?, outputs?).

    • hlsl_set is union-only: update existing entries and append missing entries.
    • It must not delete parameters or outputs.
    • Use parameters for Custom node inputs such as {"name":"Intensity","kind":"Scalar"}.
    • Use outputs for root material outputs such as "Roughness", "Metallic", "Normal", or objects with name, target, and type.
    • Additional outputs are UE5.8 Custom node AdditionalOutputs; assign same-name variables in HLSL, for example Roughness = 0.35;.
  4. Delete with hlsl_delete(names, confirm_delete=true, kind?).

    • Omit kind in the normal path.
    • If a name matches both parameter and output, expect failure with requires_kind: true; retry with kind="parameter" or kind="output".
    • Do not use hlsl_delete_parameter or hlsl_delete_output in primary flows; they are compatibility aliases.
  5. Compile with hlsl_compile.

    • Treat compile diagnostics as the feedback loop.
    • Prefer small repair writes with hlsl_set(hlsl=...) rather than resetting the target.
Show full SKILL.md (109 more words)Show less

Protocol Rules

  • The material is represented as one HLSL program on a single Custom node.
  • The Custom node primary return is float4.
  • output_contract describes where rgb/a and any additional outputs are wired.
  • UI, PostProcess, LightFunction, and Unlit output rgb to EmissiveColor; lit Surface output rgb usually maps to BaseColor.
  • Alpha maps only when semantically useful: UI/translucent to Opacity, masked to OpacityMask.
  • Do not fall back to legacy material_* graph editing unless the requested operation cannot be modeled by HLSL target, parameters, outputs, delete, and compile.

Validation

Use the narrowest relevant checks:

powershell
python -m py_compile Resources\Python\UmgMcpServer.py Resources\Python\Material\UMGMaterial.py Resources\Python\APITest\Material_HLSL_Type_Demo.py Resources\Python\APITest\Material_Protocol_Static_Check.py
python Resources\Python\APITest\Material_Protocol_Static_Check.py
& 'D:\UE_5.8\Engine\Build\BatchFiles\Build.bat' FabUMGMCPEditor Win64 Development -Project='D:\UE5Project\FabUMGMCP\FabUMGMCP.uproject' -NoHotReloadFromIDE -Progress
python Resources\Python\APITest\Material_HLSL_Type_Demo.py

The runtime demo requires Unreal Editor to be open and the MCP socket in Resources/Python/mcp_config.py to be reachable.

© winyunq, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 2 other files (references) in Skills/umg-material-mcp of winyunq/UnrealMotionGraphicsMCP.

  • SKILL.md
  • agents/openai.yaml
  • references/demo-cases.md

Open the folder on GitHubat commit a0494ef

Compare with similar skills

UMG Material MCP next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

UMG Material MCP compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
UMG Material MCP this skillwinyunq/UnrealMotionGraphicsMCP210—~913Automated safety check: PassMIT
Unreal Blueprint Authoringflopperam/unreal-engine-mcp1.1k—~1.6kAutomated safety check: PassNone
Unreal Material and VFX Workflowflopperam/unreal-engine-mcp1.1k—~927Automated safety check: PassNone
Unreal Engine MCPEpicGames/unreal-engine-skills-for-claude-code-plugin338—~1.8kAutomated safety check: PassMIT
Unreal Scene Buildingflopperam/unreal-engine-mcp1.1k—~1.4kAutomated safety check: PassNone
Unreal Engine MCP Overviewflopperam/unreal-engine-mcp1.1k—~1.7kAutomated safety check: PassNone

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Questions about UMG Material MCP

What does UMG Material MCP do?

Creates, edits and compiles Unreal Engine 5.8 material assets as one HLSL Custom node through the UMG MCP bridge, instead of editing .uasset files directly. The skill keeps a material as a single HLSL program on a Custom node and works through five MCP tools: hlsl_set_target to create or select the material and its UI or non-UI type such as domain, blend mode and shading model, hlsl_get to read the current HLSL text, parameters and output contract as semantic state, hlsl_set to write HLSL, parameters or outputs as a union-only update that can add or change entries but never delete one, hlsl_delete to remove a named parameter or output with confirmation, and hlsl_compile to compile and surface diagnostics as the feedback loop.

When should I use UMG Material MCP?

UMG Material MCP fits situations like: creating a new UI material in Unreal Engine through the MCP bridge; adding a custom parameter or output to an existing material's HLSL; debugging a material compile error through the HLSL feedback loop.

How do I install UMG Material MCP in Claude Code?

Run `npx skills add winyunq/UnrealMotionGraphicsMCP --skill umg-material-mcp -a claude-code`. Or copy the skill folder (Skills/umg-material-mcp in winyunq/UnrealMotionGraphicsMCP) into .claude/skills/umg-material-mcp in your project. Claude Code loads it when a task matches its description.

How do I install UMG Material MCP in Codex?

Run `npx skills add winyunq/UnrealMotionGraphicsMCP --skill umg-material-mcp -a codex`. Or copy the skill folder (Skills/umg-material-mcp in winyunq/UnrealMotionGraphicsMCP) into .agents/skills/umg-material-mcp in your project. Codex loads it when a task matches its description.

Can I use UMG Material MCP in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add winyunq/UnrealMotionGraphicsMCP --skill umg-material-mcp -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/umg-material-mcp, .gemini/skills/umg-material-mcp, .github/skills/umg-material-mcp and .opencode/skills/umg-material-mcp in your project.

What does UMG Material MCP need to run?

Going by SKILL.md and its folder, UMG Material MCP needs the command-line tools its instructions call (python). Our summary lists: Unreal Engine 5.8 with the UMG MCP bridge running.

Does UMG Material MCP access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is UMG Material MCP safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does UMG Material MCP use?

UMG Material MCP is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does UMG Material MCP use?

About 913 tokens (SKILL.md is roughly 3.7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 724 tokens, read only when the agent opens those files.

What are the alternatives to UMG Material MCP?

Skills that share tags, products or a category with UMG Material MCP: Unreal Blueprint Authoring (flopperam/unreal-engine-mcp, 1.1k stars), Unreal Material and VFX Workflow (flopperam/unreal-engine-mcp, 1.1k stars), Unreal Engine MCP (EpicGames/unreal-engine-skills-for-claude-code-plugin, 338 stars) and Unreal Scene Building (flopperam/unreal-engine-mcp, 1.1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains UMG Material MCP?

winyunq (a GitHub user) maintains it in winyunq/UnrealMotionGraphicsMCP, which has 210 GitHub stars. The repository holds 2 skills in this directory. The repository was last updated on August 2, 2026.

Source: winyunq/UnrealMotionGraphicsMCP on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.