A project-specific guide for adding MCP tools to mcp-unreal, an Unreal Engine plugin that exposes tools to an AI agent. It describes the code structure, registration process, tests, documentation, and checks to run.

Use it when creating a tool input and output type, implementing its handler, registering it in the server, updating the README, and running tests and linting.

It gives new tools a consistent shape and helps prevent missing tests, registrations, documentation, or validation steps.

How remiphilippe/mcp-unreal configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to remiphilippe/mcp-unreal. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/remiphilippe/mcp-unreal/main/.claude/skills/go-mcp-tool/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/remiphilippe/mcp-unreal

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/remiphilippe/mcp-unreal/go-mcp-tool/github.svg)](https://agentmods.dev/skills/remiphilippe/mcp-unreal/go-mcp-tool)

Your own site

<a href="https://agentmods.dev/skills/remiphilippe/mcp-unreal/go-mcp-tool"><img src="https://agentmods.dev/badge/skills/remiphilippe/mcp-unreal/go-mcp-tool/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/remiphilippe/mcp-unreal/go-mcp-tool"><img src="https://agentmods.dev/badge/skills/remiphilippe/mcp-unreal/go-mcp-tool.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 205 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00017	$0.00205
Opus 5.5	$0.00007	$0.00082
Sonnet 5.5	$0.00003	$0.00041
Haiku 4.5	$0.00002	$0.00020

Measured 2mo ago against content hash 6a1f5b3876b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

go-mcp-tool scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/go-mcp-tool/SKILL.md · 26 lines

What it actually says

Adding a New Tool

Create input/output types in the appropriate internal/ package
Implement the handler method on the package's Handler struct
Register in cmd/mcp-unreal/main.go with descriptive tool name + description
Add tests with table-driven patterns
Update README.md tool table
Run go test ./... && golangci-lint run

Template

type MyToolInput struct {
    Param string `json:"param" jsonschema:"required,Description here"`
}
type MyToolOutput struct {
    Result string `json:"result"`
}
func (h *Handler) MyTool(ctx context.Context, req *mcp.CallToolRequest, input MyToolInput) (*mcp.CallToolResult, MyToolOutput, error) {
    // validate, execute, return
}

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 26 lines · 17 tokens per session scan A 6a1f5b3876b9

Subscribe to this mod's changes

go-mcp-tool is a skill published in the GitHub repository remiphilippe/mcp-unreal (81 stars, last pushed 8mo ago), licensed Apache-2.0. It adds 17 tokens to every session and 205 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Building agents Game development mcp-server unreal-engine unreal-engine-5

go-mcp-tool next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
go-mcp-toolremiphilippe/mcp-unreal	Skill	81	8mo ago	Apache-2.0	A	17	Claude Code
asset-managementkevinpbuckley/VibeUE	Skill	812	2d ago	MIT	A	130	Claude Code, Codex
level-actorskevinpbuckley/VibeUE	Skill	812	2d ago	MIT	A	64	Claude Code, Codex
vibeuekevinpbuckley/VibeUE	Skill	812	2d ago	MIT	A	82	Claude Code, Codex
materialskevinpbuckley/VibeUE	Skill	812	2d ago	MIT	A	95	Claude Code, Codex
project-settingskevinpbuckley/VibeUE	Skill	812	2d ago	MIT	A	61	Claude Code, Codex
enhanced-inputkevinpbuckley/VibeUE	Skill	812	2d ago	MIT	A	66	Claude Code, Codex

mcp-unreal: Skill for Claude Code