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 SummerEngine/summer-engine-agent --skill gameskillgit clone --depth 1 https://github.com/SummerEngine/summer-engine-agentWrote 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/summerengine/summer-engine-agent/gameskill)<a href="https://agentmods.dev/skills/summerengine/summer-engine-agent/gameskill"><img src="https://agentmods.dev/badge/skills/summerengine/summer-engine-agent/gameskill/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/summerengine/summer-engine-agent/gameskill"><img src="https://agentmods.dev/badge/skills/summerengine/summer-engine-agent/gameskill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 7 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
- medium MCP Rug Pull · line 24 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
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 | $0.00056 | $0.02183 |
| Opus 5 | $0.00028 | $0.01092 |
| Sonnet 5 | $0.00011 | $0.00437 |
| Haiku 4.5 | $0.00006 | $0.00218 |
Grade A, and why
gameskill 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 6d 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 — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
/gameskill — Capture Session Learnings into the Skill Library
You're being invoked at the end (or middle) of a game-development session. Your job is to turn what you just figured out into a durable skill update so future agents and Summer users get to start where you ended.
This is the meta-skill: the loop that turns ad-hoc fixes into reusable expertise.
What "Summer Engine" is, so you're grounded
Three repos, one ecosystem:
- SummerEngine repo — the Summer Engine desktop source plus the canonical
CLI. The C++ engine is maintained against the upstream Godot Engine codebase;
the Summer-owned module lives at
modules/1summer_engine/. CLI source lives attools/summer-cli/and is normally invoked withnpx -y summer-engine@latest. It installs, signs in, creates, and runs Summer projects and can install the current Summer skill bundle for supported agents. - PublicSummerEngine repo — the web app at summerengine.com. Has its own AI skill stores at
src/lib/ai/skills/bundled/andpublic/knowledge/summer/skills/for the in-browser chat agent. Also has its own consumers of the engine API insrc/lib/bridge/direct-executor.tsandsrc/lib/ai/tools/run-and-verify.tswhich call the same engine endpoints the CLI does. - The active Summer game project — usually
~/development/<game-name>or whatever game you were just working on. The live compatibility line comes from Summer Engine, not this prompt. Real working code in this repo is the gold standard for examples.
The skill system is the value flywheel. Every game shipped teaches lessons. Lessons become skills. Next user starts smarter. Your job here is to close that loop for what you just did.
Cross-repo change awareness — read before any non-trivial fix
When the lesson is "the engine should expose more / behave differently," the change usually crosses repo boundaries. Map the layers before you edit:
[active game] -> calls MCP / web app
v
[summer-cli MCP server (TypeScript)] -> calls /api/ops + /api/state/* on the engine
v
[Summer Engine binary (C++ in SummerEngine repo)] - source of truth for what the API returns
[PublicSummerEngine web app (TypeScript)] -> also calls the same engine endpoints via direct-executor or Redis bridge
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.
- 6d ago First seen · 121 lines · 56 tokens per session scan A afc06bd229e9
gameskill is a skill published in the GitHub repository SummerEngine/summer-engine-agent (59 stars, last pushed yesterday), licensed MIT. It adds 56 tokens to every session and 2,183 once invoked, about $0.0003 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
self-evolve
Capture reusable patterns from a finished project and lift them into framework-level priors (contracts, modules, skeletons) that future projects inherit. Run only when the user explicitly requests self-evolution; the orchestrator executes the workflow.
artist-self-evolve
Distill stable art-generation patterns from a completed project, so future projects produce comparable assets without re-discovering the prompts. Lead-dispatched only — orchestrator invokes this skill from its self-evolve flow with a game-slug message; do not self-trigger.
vibegame-build
Run VibeGame's standard end-to-end game development workflow with reviewer gates. Use when the user wants to create a game from zero or evolve an existing game across multiple stages.
vibegame-start
Resume a VibeGame orchestrator session after vibegame start. Use at the beginning of a Claude or Codex session to inspect team runtime state, repair missing persistent members, load goal and GDD context, inspect tasks, and ask the user what to do next.
vibegame-edit
Iterate broadly on an existing game, on top of vibegame-build. Use when the user asks to change an existing game's art style, genre, or core rules. Not for local tuning such as numbers or game feel. Orchestrator only.
hearth-feel
Make a Hearth game feel good, not just run — the juice stack (hit-stop, screen shake, flash, particle bursts, layered sound), tween easing, camera effects, anticipation/recovery animation idioms, game-UX conventions (menus, pause, onboarding, difficulty, save etiquette), effect-asserting playtests, and the quality bar…