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-collision-and-trace-contractgit 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-collision-and-trace-contract)<a href="https://agentmods.dev/skills/lichamnesia/unreal-engine-agent-skills/ue5-collision-and-trace-contract"><img src="https://agentmods.dev/badge/skills/lichamnesia/unreal-engine-agent-skills/ue5-collision-and-trace-contract/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-collision-and-trace-contract"><img src="https://agentmods.dev/badge/skills/lichamnesia/unreal-engine-agent-skills/ue5-collision-and-trace-contract.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 | $0.00117 | $0.01525 |
| Opus 5 | $0.00059 | $0.00763 |
| Sonnet 5 | $0.00023 | $0.00305 |
| Haiku 4.5 | $0.00012 | $0.00153 |
Grade A, and why
ue5-collision-and-trace-contract 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 11d 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 — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Collision and Trace Contract
Collision configuration in UE5 has a property that makes it unusually easy to get wrong: it is global, shared, and mostly invisible from the code that depends on it. A query in one file behaves the way it does because of a channel definition in project settings and a response set on a component in a different asset. None of the three references the others, and all three have to agree.
The consequences are the two complaints that dominate hit-detection debugging — "the trace returns nothing" and "the trace hits things it should not" — and both are usually correct code running against a configuration nobody wrote down.
The second failure is worse and quieter: a fast object passing through thin geometry, which is not a configuration problem at all but a query-type problem, and which reproduces only at speed.
Settle the hit contract first
- Define what a hit means for each interaction before choosing an API. What is being asked, what may answer, and what the answer authorizes. A trace is a question; most trace bugs are a well-formed answer to the wrong question.
- Write down the channel semantics. Two different kinds of channel exist and they
answer different questions — an object channel says what a thing is, a trace channel
says what a query is looking for. Confusing them is the single most common
configuration error. See
references/channel-semantics.md. - Never reuse a general-purpose channel for a gameplay decision. Visibility and camera channels exist, are always available, and mean something else. Borrowing one couples your hit logic to rendering and camera concerns permanently.
- Treat the response matrix as shared state with an owner. Every channel added is a column every existing object must have an opinion about. Changing one response can alter behavior in systems that never mention it.
- Choose the query type from speed and size, not from convenience. A line has zero
thickness and objects move in discrete steps; both facts produce misses that look like
configuration bugs. See
references/query-selection.md. - Name one system as the hit authority for each interaction. Two systems independently
querying will eventually disagree, and the disagreement surfaces as an intermittent
gameplay inconsistency. See
references/hit-authority.md.
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.
- 11d ago First seen · 117 lines · 117 tokens per session scan A 3afab8410b7f
ue5-collision-and-trace-contract is a skill published in the GitHub repository LichAmnesia/unreal-engine-agent-skills (5 stars, last pushed 27d ago), licensed MIT. It adds 117 tokens to every session and 1,525 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.
Other skills, from other repositories
gameobject-component-destroy
Destroy one or more Components from a target GameObject. Missing (null) components are skipped — they cannot be destroyed. Use 'gameobject-find' and 'gameobject-component-get' to identify the components first.
unity-version-split
Split a C# file into Unity 6.5+ and pre-Unity 6.5 variants. Use when a file needs different implementations for different Unity versions due to API changes (e.g., EntityId vs int, GetEntityId vs GetInstanceID).
godot-signals-groups
Build event-driven, decoupled Godot 4.7 gameplay with signals and node groups: declare and emit custom signals, connect with Callables (incl. bind/one-shot), and broadcast to many nodes via groups and callgroup. Use when wiring node communication in a Godot project, replacing tight references with signals…
unity-addressables
Manage Addressables groups, entries, profiles and content builds (com.unity.addressables, reflection-based).
motion
How an agent turns a character mesh into a usable animated FBX — and how to judge whether the result is shippable.
threejs-exposure-color-grading
Build a measured exposure and grading path in Three.js. Use for a 64x36 encoded luminance meter, asynchronous readback, weighted log-average exposure, asymmetric adaptation, single tone-map ownership, and a generated 32-cube post-tone-map LUT.