gameskill

gameskill is a command for coding agents from SummerEngine/summer-engine-agent. It costs 0 tokens per session (2,094 once invoked), scanned A, original, MIT.

A command for recording lessons from a game-development session in Summer Engine’s shared skill library. Summer Engine is a game-development system with an engine, command-line tools, and related web services.

In plain words
What is it for?
Use it after a development session to capture reusable knowledge about Summer Engine projects, its command-line tools, or its connected repositories.
Why use it?
It preserves useful fixes and discoveries so later agents and users can reuse them instead of starting from the same problem again.

Command

Part of the summer plugin — 51 skills, 2 commands, 2 hooks, 1 MCP server shipped together

Install

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.

agentmods
npx agentmods add commands/summerengine/summer-engine-agent/gameskill
Clone the repo
git clone --depth 1 https://github.com/SummerEngine/summer-engine-agent

Or install summer, the plugin that ships this one along with the rest of its 51 skills, 2 commands, 2 hooks, 1 MCP server.

Wrote 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.

agentmods badge for gameskill

README.md
[![agentmods](https://agentmods.dev/badge/commands/summerengine/summer-engine-agent/gameskill.svg)](https://agentmods.dev/commands/summerengine/summer-engine-agent/gameskill)
Your own site
<a href="https://agentmods.dev/commands/summerengine/summer-engine-agent/gameskill"><img src="https://agentmods.dev/badge/commands/summerengine/summer-engine-agent/gameskill.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,094 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.02094
Opus 5 $0.00000 $0.01047
Sonnet 5 $0.00000 $0.00419
Haiku 4.5 $0.00000 $0.00209

Measured 4d ago against content hash 5434c71dd43a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 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.

commands/gameskill.md · 113 lines

How it starts

The opening of the file, as written. The whole thing — 113 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are capturing what we just learned in this game-development session into Summer Engine's skill library, so the next agent (and every Summer user) gets to start where we ended.

This is the meta-skill: the loop that turns ad-hoc fixes into durable, reusable expertise.

What "Summer Engine" is, so you're grounded

Three repos, one ecosystem:

  1. ~/development/SummerEngine — the Summer Engine desktop source and the canonical CLI. The C++ engine is maintained against the upstream Godot Engine codebase; the Summer-owned module lives at modules/1summer_engine/. The Summer CLI lives at tools/summer-cli/ and is normally invoked with npx -y summer-engine@latest. It installs, signs in, creates, and runs Summer projects and can install the current Summer skill bundle for supported agents.
  2. ~/development/PublicSummerEngine — the web app at summerengine.com. Has its own AI skill stores at src/lib/ai/skills/bundled/ and public/knowledge/summer/skills/ for the in-browser chat agent. ALSO has its own MCP-style consumers of the engine API (src/lib/bridge/direct-executor.ts, src/lib/ai/tools/run-and-verify.ts) which call the same engine endpoints the CLI does.
  3. The active Summer game project — usually ~/development/<game-name> or whatever game we 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 we ship teaches lessons → the lessons become skills → the next user (or AI) starts smarter. Your job here is to close that loop for what we just did.

Cross-repo change awareness — read this 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
                       ↓
[summer-cli MCP server (TypeScript)] → calls /api/ops + /api/state/* on the engine
                       ↓
[Summer Engine binary (C++ in SummerEngine repo)] — source of truth for what the API can return

[PublicSummerEngine web app (TypeScript)] → also calls the same engine endpoints via direct-executor or Redis bridge

Read the full file on GitHub · 113 lines

Changes

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.

  1. 4d ago First seen · 113 lines · 0 tokens per session scan A 5434c71dd43a

Subscribe to this mod's changes

gameskill is a command published in the GitHub repository SummerEngine/summer-engine-agent (57 stars, last pushed today), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,094 tokens. 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 2026-08-30.