What is yes-ue-mcp AGENTS.md?

Repository instructions for yes-ue-mcp, a C++ plugin for Unreal Engine that lets AI assistants inspect and change projects through a standard tool protocol. They cover its two-part design, build commands, and tests.

Use them when building the Unreal Engine plugin, regenerating project files, or running its integration tests with the editor.

They explain how to compile the plugin and verify its HTTP-based tool interface without guessing at Unreal Engine commands.

How softdaddy-o/yes-ue-mcp configures Codex and OpenCode

Reuse

Borrowing it

Nothing to install: this file belongs to softdaddy-o/yes-ue-mcp. 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/softdaddy-o/yes-ue-mcp/main/AGENTS.md

Clone the repo

git clone --depth 1 https://github.com/softdaddy-o/yes-ue-mcp

Made for: Codex, OpenCode.

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/instructions/softdaddy-o/yes-ue-mcp/agents-md.svg)](https://agentmods.dev/instructions/softdaddy-o/yes-ue-mcp/agents-md)

Your own site

<a href="https://agentmods.dev/instructions/softdaddy-o/yes-ue-mcp/agents-md"><img src="https://agentmods.dev/badge/instructions/softdaddy-o/yes-ue-mcp/agents-md.svg" alt="Measured on agentmods" height="20"></a>

Per session 2,529 This file is loaded in full into every session.

When invoked 2,529 The same file — it is already loaded in full.

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	$0.02529	$0.02529
Opus 5	$0.01264	$0.01264
Sonnet 5	$0.00506	$0.00506
Haiku 4.5	$0.00253	$0.00253

Measured 8d ago against content hash ddadcfd5cde3, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

yes-ue-mcp AGENTS.md 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 8d 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.

AGENTS.md · 301 lines

How it starts

The opening of the file, as written. The whole thing — 301 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md - Development Guide for yes-ue-mcp

This guide provides agentic coding agents with the essential information to work effectively in the yes-ue-mcp codebase.

Project Overview

yes-ue-mcp is a native C++ Unreal Engine plugin implementing the Model Context Protocol (MCP) over HTTP. It enables AI assistants to inspect, analyze, and modify UE projects through a standardized JSON-RPC API.

Type: Unreal Engine 5.6+ C++ plugin
Architecture: Two-module system (Runtime + Editor)
Protocol: MCP 2025-03-26 (Streamable HTTP) with JSON-RPC 2.0
Transport: HTTP server on localhost:8080/mcp

Build System & Commands

Build Commands

# Build plugin with UnrealBuildTool
<UE>/Engine/Build/BatchFiles/Build.bat YourProjectEditor Win64 Development

# Regenerate project files after adding files
<UE>/Engine/Binaries/DotNET/UnrealBuildTool/UnrealBuildTool.exe -projectfiles -project="YourProjectPath/YourProject.uproject" -game -rocket -progress

Test Commands

# Run Python integration tests (requires UE Editor running with plugin)
cd Tests
python -m pytest test_mcp_tools.py -v
python -m unittest test_mcp_tools -v
python test_mcp_tools.py

# Run single test
python -m pytest test_mcp_tools.py::TestConnection::test_server_responds -v

Environment Variables for Testing

MCP_HOST: MCP server host (default: 127.0.0.1)
MCP_PORT: MCP server port (default: 8080)

Development Workflow

# Deploy plugin to test projects
.\copy_plugin.ps1                    # Copy to both projects
.\copy_plugin.ps1 -Target Elpis      # Copy to Elpis only
.\copy_plugin.ps1 -Target GameAnim   # Copy to GameAnimationSample56 only

Code Style Guidelines

General Conventions

Follow Epic Games C++ coding standards
Use YESUEMCP_API / YESUEMCPEDITOR_API for exported symbols
Use TEXT() macro for string literals
Use TEXT() for log messages and UE API calls

Read the full file on GitHub · 301 lines

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.

8d ago First seen · 301 lines · 2,529 tokens per session scan A ddadcfd5cde3

Subscribe to this mod's changes

yes-ue-mcp AGENTS.md is an instructions file published in the GitHub repository softdaddy-o/yes-ue-mcp (88 stars, last pushed 5mo ago), licensed MIT. It adds 2,529 tokens to every session, about $0.0126 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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