mcp-unreal: Skill for Claude Code

.claude/skills/go-mcp-tool/SKILL.md

go-mcp-tool is a skill for Claude Code from remiphilippe/mcp-unreal. It costs 17 tokens per session (205 once invoked), scanned A, original, Apache-2.0.

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.

In plain words
What is it for?
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.
Why use it?
It gives new tools a consistent shape and helps prevent missing tests, registrations, documentation, or validation steps.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is remiphilippe/mcp-unreal's own configuration. It tells Claude Code how to work on mcp-unreal itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything mcp-unreal configures →

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.

agentmods badge for go-mcp-tool

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.

agentmods 80×15 button for go-mcp-tool

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00017 $0.00205
Opus 5 $0.00009 $0.00102
Sonnet 5 $0.00003 $0.00041
Haiku 4.5 $0.00002 $0.00020

Measured 12d ago against content hash 6a1f5b3876b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, 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 12d 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

  1. Create input/output types in the appropriate internal/ package
  2. Implement the handler method on the package's Handler struct
  3. Register in cmd/mcp-unreal/main.go with descriptive tool name + description
  4. Add tests with table-driven patterns
  5. Update README.md tool table
  6. 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.

  1. 12d 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 (69 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 17 tokens to every session and 205 once invoked, about $0.0001 per session on Opus 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.

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