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.
npx skills add LichAmnesia/unreal-engine-agent-skills --skill ue5-authoritative-vs-cosmeticgit clone --depth 1 https://github.com/LichAmnesia/unreal-engine-agent-skillsWrote 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.
[](https://agentmods.dev/skills/lichamnesia/unreal-engine-agent-skills/ue5-authoritative-vs-cosmetic)<a href="https://agentmods.dev/skills/lichamnesia/unreal-engine-agent-skills/ue5-authoritative-vs-cosmetic"><img src="https://agentmods.dev/badge/skills/lichamnesia/unreal-engine-agent-skills/ue5-authoritative-vs-cosmetic/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.
<a href="https://agentmods.dev/skills/lichamnesia/unreal-engine-agent-skills/ue5-authoritative-vs-cosmetic"><img src="https://agentmods.dev/badge/skills/lichamnesia/unreal-engine-agent-skills/ue5-authoritative-vs-cosmetic.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00113 | $0.01512 |
| Opus 5 | $0.00056 | $0.00756 |
| Sonnet 5 | $0.00023 | $0.00302 |
| Haiku 4.5 | $0.00011 | $0.00151 |
Grade A, and why
ue5-authoritative-vs-cosmetic 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.
How it starts
The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Authoritative vs. Cosmetic
Presentation in UE5 is allowed to lie. That is its job: animation moves bones, suspension tilts a body, camera shake displaces a view, interpolation smooths a position, and a simulated visual mesh drifts from the logical one. All of that is correct, and all of it happens after the values gameplay should have used.
The failure is reading gameplay truth out of that layer. It produces bugs with a characteristic signature: the error is proportional to how much the decoration is moving, it is invisible when the scene is still, and it cannot be found by debugging the system that appears wrong. A fraction of a degree of cosmetic tilt at the origin becomes a large error at the target, and every hour spent tuning the system that reports the error is wasted, because the error was injected upstream.
The fix is not a code change. It is deciding, per quantity, which representation is authoritative — and then never letting the other one reach a decision.
Settle the authority contract first
- List the quantities gameplay decides on — origin and direction of anything spawned or traced, positions used by AI, distances used by rules, velocities used by prediction.
- For each, name one authoritative source, and write it down. If two sources exist and neither is named, code will pick the convenient one, which is almost always the cosmetic one because it is what the visuals already use.
- Classify every transform in the actor as authoritative or cosmetic. Anything an
animation, IK solver, spring, smoothing component, physics visual body, or camera modifier
can touch is cosmetic — even when it is currently equal to the authoritative value. See
references/authority-map.md. - Give gameplay its own attachment points when it needs a location on a moving actor, rather than reusing the visual ones. Two sockets that agree today is not the same thing as one socket; the second one is free and it cannot drift.
- Let presentation read simulation, never the reverse. One-way dependency. A cosmetic value that feeds back into a gameplay value creates an error that grows with visual intensity.
What ships with it
4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 12d ago First seen · 111 lines · 113 tokens per session scan A 5b9d2e57e449
ue5-authoritative-vs-cosmetic is a skill published in the GitHub repository LichAmnesia/unreal-engine-agent-skills (5 stars, last pushed 28d ago), licensed MIT. It adds 113 tokens to every session and 1,512 once invoked, about $0.0006 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 2026-08-31.
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