# create_material_function

Create a reusable material function.

Agent View of the PolicyLayer registry record for `create_material_function`. HTML page: https://policylayer.com/tools/jjpxdev-unreal-mcp/create-material-function

## Facts

- Tool: `create_material_function`
- Server: Unreal (`@jjpxdev/unreal-mcp`) — https://policylayer.com/tools/jjpxdev-unreal-mcp.md
- Install: `npx -y @jjpxdev/unreal-mcp`
- Homepage: https://www.npmjs.com/package/@jjpxdev/unreal-mcp
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 2 (1 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `name` | string | yes | Material function name |
| `path` | string | no | Content directory |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create_material_function",
    "arguments": {
      "name": "<name>"
    }
  }
}
```

## Why create_material_function is rated Medium

This tool creates new material functions, which are reversible asset modifications in Unreal Engine. It does not execute arbitrary code, delete assets, move money, or trigger external operations with unpredictable effects.

From the tool's own definition: "Tool name is 'create_material_function' and description states 'Create a reusable material function.' The verb 'create' indicates data creation/modification within Unreal Engine's material system."

Risk signals: Accepts file system path (path)

## Use case

AI agents use create_material_function to create or update resources in Unreal, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Unreal environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Unreal:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_material_function": {
      "limits": [
        {
          "counter": "create_material_function_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Unreal (126)

- `delete_actor` — Destructive — https://policylayer.com/tools/jjpxdev-unreal-mcp/delete-actor.md
- `delete_asset` — Destructive — https://policylayer.com/tools/jjpxdev-unreal-mcp/delete-asset.md
- `delete_material_expression` — Destructive — https://policylayer.com/tools/jjpxdev-unreal-mcp/delete-material-expression.md
- `remove_graph_node` — Destructive — https://policylayer.com/tools/jjpxdev-unreal-mcp/remove-graph-node.md
- `build_cook_run` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/build-cook-run.md
- `build_graph` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/build-graph.md
- `build_plugin` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/build-plugin.md
- `build_target` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/build-target.md
- `call_preset_function` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/call-preset-function.md
- `clean_project` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/clean-project.md
- `compile_blueprint` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/compile-blueprint.md
- `content_audit` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/content-audit.md
- `cook_content` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/cook-content.md
- `execute_console_command` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/execute-console-command.md
- `execute_python` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/execute-python.md
- `generate_lods` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/generate-lods.md
- `package_project` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/package-project.md
- `recompile_material` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/recompile-material.md
- `reinit_niagara_system` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/reinit-niagara-system.md
- `render_sequence` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/render-sequence.md
- `reset_niagara_system` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/reset-niagara-system.md
- `run_all_automation_tests` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-all-automation-tests.md
- `run_automation_test` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-automation-test.md
- `run_automation_tests_by_category` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-automation-tests-by-category.md
- `run_editor_utility_blueprint` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-editor-utility-blueprint.md
- `run_editor_utility_widget` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-editor-utility-widget.md
- `run_gauntlet` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-gauntlet.md
- `run_map_check` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-map-check.md
- `run_stat_command` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/run-stat-command.md
- `spawn_niagara_at_location` — Execute — https://policylayer.com/tools/jjpxdev-unreal-mcp/spawn-niagara-at-location.md
- …and 96 more: https://policylayer.com/tools/jjpxdev-unreal-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=jjpxdev-unreal-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/jjpxdev-unreal-mcp