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-multiplayergit 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-multiplayer)<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/gamedev-multiplayer"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/gamedev-multiplayer.svg" alt="Measured on agentmods" 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 | $0.00086 | $0.03808 |
| Opus 5 | $0.00043 | $0.01904 |
| Sonnet 5 | $0.00017 | $0.00762 |
| Haiku 4.5 | $0.00009 | $0.00381 |
Grade A, and why
gamedev-multiplayer 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 4d 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 — 238 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Game multiplayer & netcode
Design and wire the network layer of a game across Godot 4.x, Unity, and Unreal: choose a topology, put authority in the right place, replicate the right state, and hide latency without opening the door to cheaters. This skill owns the networking decisions; the engine skills own the local gameplay those decisions sit on top of.
Route elsewhere when the ask is not netcode:
| The ask | Route to | Why not here |
|---|---|---|
| Single-player movement, AI, input, animation, save files | godot / unity / unreal |
The engine skill owns local gameplay; no network dimension. |
| Physics determinism, collision, character controllers | gamedev-physics |
Netcode consumes determinism; it does not own the physics fix. |
| Matchmaking, lobby backend, dedicated-server hosting, relays, DB, game-server CI | deployment |
Running the fleet, not designing the in-game net layer. |
| Web realtime — chat, presence, a generic WebSocket app | webhooks |
Not a game world/simulation. |
| General threat modeling, authz review | secure-coding |
This skill keeps only the game-specific anti-cheat controls. |
Version contract — read first
Target the current APIs. Never emit these deprecated / removed APIs:
| Engine | Target | Banned (removed/legacy) | Emit instead |
|---|---|---|---|
| Godot | 4.x | master/puppet/remote/sync keywords, rpc_config() as a func, rset, NetworkedMultiplayerENet |
@rpc(...) annotation, set_multiplayer_authority(), ENetMultiplayerPeer, MultiplayerSynchronizer |
| Unity | Netcode for GameObjects (NGO) 1.x/2.x | UNet / HLAPI: NetworkIdentity, [Command], [SyncVar], NetworkServer, UnityEngine.Networking |
NGO NetworkObject, NetworkBehaviour, NetworkVariable<T>, [Rpc(SendTo.X)] |
| Unreal | 5.x | replicating by polling in Tick, skipping WithValidation on gameplay RPCs |
UPROPERTY(Replicated / ReplicatedUsing=...) + GetLifetimeReplicatedProps, Server/Client/NetMulticast UFUNCTIONs |
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.
- 4d ago First seen · 238 lines · 86 tokens per session scan A f6a3ecedbaa4
gamedev-multiplayer is a skill published in the GitHub repository ericrisco/rsc-harness (70 stars, last pushed today), licensed MIT. It adds 86 tokens to every session and 3,808 once invoked, about $0.0004 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.
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