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 ericrisco/rsc-harness --skill gamedev-physicsgit clone --depth 1 https://github.com/ericrisco/rsc-harnessWrote 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/ericrisco/rsc-harness/gamedev-physics)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/gamedev-physics"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/gamedev-physics/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/ericrisco/rsc-harness/gamedev-physics"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/gamedev-physics.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00102 | $0.03739 |
| Opus 5 | $0.00051 | $0.01869 |
| Sonnet 5 | $0.00020 | $0.00748 |
| Haiku 4.5 | $0.00010 | $0.00374 |
Grade A, and why
gamedev-physics 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 5d 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 — 226 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Game physics & collision
Make bodies collide, move, and stay stable across Godot, Unity, and Unreal. This skill owns the mental model (body types, colliders, layers/masks, character controllers, joints, queries, determinism) and maps every concept onto each engine's real API. When physics "feels broken" — jitter, tunneling, sinking, ghost collisions — the cause is almost always one of: wrong body type, a layer/mask mismatch, or moving/integrating outside the fixed physics tick. Check those first.
Version contract — read first (never emit these)
| Engine | Target | Banned / deprecated | Use instead |
|---|---|---|---|
| Godot | 4.x | move_and_slide(velocity, up, ...) with arguments (that is Godot 3) |
Godot 4 move_and_slide() takes no args; set the velocity property first |
| Godot | 4.x | KinematicBody2D/3D, RayShape, WorldMarginShape, linear_velocity *= delta before move_and_slide() |
CharacterBody2D/3D, SeparationRayShape2D/3D, WorldBoundaryShape2D/3D; move_and_slide() is already delta-scaled |
| Unity | Unity 6 (6000.x) | Rigidbody.velocity / Rigidbody2D.velocity, rb.drag, rb.angularDrag |
linearVelocity (+ linearVelocityX/Y), linearDamping, angularDamping; new AddForceX/Y |
| Unity | Unity 6 | moving a dynamic Rigidbody from Update; transform.position = on a physics body |
move in FixedUpdate; use MovePosition/AddForce, never write transform on a simulated body |
| Unreal | UE5 (Chaos) | any PhysX/APEX API, bUseAsyncScene, NvCloth |
Chaos is the only physics backend in UE5; use UPrimitiveComponent physics + PhysicsConstraintComponent |
If you are unsure a symbol exists in the user's exact version, say so instead of inventing it.
When to use / When NOT to use
Use when: designing which body type a thing should be; something falls through, sinks into, or passes through geometry; a rigid body jitters, drifts, or launches; setting up collision layers/masks/channels; building or fixing a character/player controller; adding joints; casting rays/shapes or overlap tests; or physics behaves differently at different frame rates.
What ships with it
5 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.
- 5d ago First seen · 226 lines · 102 tokens per session scan A 85164aabe41f
gamedev-physics is a skill published in the GitHub repository ericrisco/rsc-harness (70 stars, last pushed yesterday), licensed MIT. It adds 102 tokens to every session and 3,739 once invoked, about $0.0005 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 2026-09-03.
Other skills, from other repositories
codegraph
Analyze indexed codebases via graph database (neug) and vector index (zvec). Covers call graphs, dependencies, dead code, hotspots, module coupling, architecture reports, semantic search, impact analysis, bug root cause from GitHub issues, class diagrams (UML), and PR review (risk scoring, conflict detection…
stuck
Diagnose frozen, stuck, or slow Qwen Code sessions on this machine. Scans for problematic processes, high CPU/memory usage, hung subprocesses, and debug logs. Use /stuck or /stuck to focus on a specific process.
structured-debugging
Hypothesis-driven debugging methodology for hard bugs. Use this skill whenever you're investigating non-trivial bugs, unexpected behavior, flaky tests, or tracing issues through complex systems. Activate proactively when debugging requires more than a quick glance — especially when the first attempt at a fix didn't…
autofix
Review and repair current local changes until they converge, or run Qwen Code Autofix issue and review workflows from GitHub Actions.
diagnosing-bgs-problems
A symptom-first guide for investigating crashes, frame-rate drops, stuttering, freezes, and startup failures in Bethesda Game Studios games with mods.
roam
Codebase comprehension via roam-code CLI. Use when exploring codebases, planning modifications, debugging failures, assessing PR risk, or checking architecture health. Triggers on: understanding project structure, pre-change safety checks, finding symbols/files, blast radius analysis, affected tests, health scoring…