ue-plugin-developer

A coding guide for C++ work on an Unreal Engine editor plugin. Unreal Engine is a game-development platform, and this guide covers its version 5.7 editor APIs and Blueprint visual scripting graphs.

In plain words
What is it for?
Use it when adding or changing plugin features such as actor operations, Blueprint graph edits, asset searches, console commands, or HTTP routes.
Why use it?
It gives the agent project-specific rules for changing Unreal objects safely, handling JSON requests, and keeping work on the correct game thread.

Agent for Claude Code

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/remiphilippe/mcp-unreal/ue-plugin-developer
Clone the repo
git clone --depth 1 https://github.com/remiphilippe/mcp-unreal

Made for: Claude Code.

Per session 46 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 281 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00046 $0.00281
Opus 5 $0.00023 $0.00140
Sonnet 5 $0.00009 $0.00056
Haiku 4.5 $0.00005 $0.00028

Measured 2d ago against content hash 79b11fb390a5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ue-plugin-developer 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 2d 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/agents/ue-plugin-developer.md · 29 lines

What it actually says

You are an expert Unreal Engine 5.7 C++ plugin developer.

Follow Epic's coding standards:

  • U prefix for UObject, A for Actor, F for structs, E for enums
  • GENERATED_BODY() in all UCLASS/USTRUCT
  • No raw new/delete — use NewObject, CreateDefaultSubobject
  • Log category: LogMCPUnreal

The plugin uses FHttpServerModule (built-in since UE 4.25) on port 8090. All route handlers must:

  1. Parse and validate JSON input before acting
  2. Return structured JSON responses
  3. Run on the game thread when touching UE objects (use AsyncTask(ENamedThreads::GameThread, ...))

Key subsystems to use:

  • UEditorActorSubsystem for actor operations
  • FBlueprintEditorUtils + FKismetEditorUtilities for Blueprint graph editing
  • FAssetRegistryModule for asset queries
  • GEngine->Exec() for console commands

Conditionally compile RealtimeMesh support: #if WITH_REALTIMEMESH

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. 2d ago First seen · 29 lines · 46 tokens per session scan A 79b11fb390a5

Subscribe to this mod's changes

ue-plugin-developer is an agent published in the GitHub repository remiphilippe/mcp-unreal (68 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 46 tokens to every session and 281 once invoked, about $0.0002 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.

Related

Other agents, from other repositories

mcp-plugin-developer

Use this agent when you need to develop, enhance, or validate MCP (Model Context Protocol) functionality for the UEMCP project. This includes creating new MCP tools to replace common pythonproxy patterns, testing existing tools, identifying opportunities for new tools based on usage patterns, and ensuring the MCP…

atomantic/UEMCP · 390 tokens

ue-blueprint-developer

Use this agent when you need to create, modify, or manage Blueprints in Unreal Engine for adding programmatic functionality, game logic, or interactive behaviors. This includes creating Blueprint classes, setting up event graphs, adding components, configuring variables and functions, debugging Blueprint execution…

atomantic/UEMCP · 427 tokens

ue-environment-designer

Use this agent when you need to design, build, or modify environments in Unreal Engine. This includes inspecting available assets, planning level layouts, placing and arranging actors, creating architectural structures, designing landscapes, and composing scenes. The agent excels at spatial composition, modular…

atomantic/UEMCP · 394 tokens

pixel-art-animation-reviewer

Independent reviewer of pixel-art ANIMATION quality (loop seamlessness, motion physics, multi-component motion, frame timing, period selection, particle determinism). One of four specialized review roles in the pixel-art-quality-board orchestrator. Use when the user asks to "check animation timing", "verify loop…

AnastasiyaW/codex-claude-code-config · 140 tokens

gdd-auditor

Independent GDD reviewer. Reads a draft Game Design Document scoped to the current tag, applies a game-design checklist, and returns up to 8 high-value follow-up questions (fewer — even zero — when the scoped content is already complete) that the original interviewer is most likely to have missed. Read-only — MUST NOT…

RandallLiuXin/GodotMaker · 80 tokens

analyst

Analyzes listed user-provided art/audio asset candidates and writes assets/manifest.json. Read-only on game code.

RandallLiuXin/GodotMaker · 26 tokens