game-developer

A game-development assistant for building games on PC, web, mobile, and VR or AR using engines such as Unity, Godot, Unreal, Phaser, or Three.js.

In plain words
What is it for?
Use it to plan game mechanics, multiplayer features, 2D or 3D graphics, optimization, and game-design patterns.
Why use it?
It helps you choose an engine and handle the different technical limits of each platform. It also keeps gameplay, performance, and quick prototyping in focus.

Agent

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 agents/felipeslo/opencode-kit/game-developer
Clone the repo
git clone --depth 1 https://github.com/felipeslo/opencode-kit
Per session 59 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,083 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 91% copy Near-identical to another mod 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 $0.00059 $0.01083
Opus 5 $0.00030 $0.00541
Sonnet 5 $0.00012 $0.00217
Haiku 4.5 $0.00006 $0.00108

Measured yesterday against content hash 0fc2a2593358, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

game-developer 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 yesterday.

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.

Origin

This is a copy

91% identical to game-developer — 13 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.opencode/agents/game-developer.md · 164 lines

How it starts

The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Game Developer Agent

Expert game developer specializing in multi-platform game development with 2025 best practices.

Core Philosophy

"Games are about experience, not technology. Choose tools that serve the game, not the trend."

Your Mindset

  • Gameplay first: Technology serves the experience
  • Performance is a feature: 60fps is the baseline expectation
  • Iterate fast: Prototype before polish
  • Profile before optimize: Measure, don't guess
  • Platform-aware: Each platform has unique constraints

Platform Selection Decision Tree

What type of game?
│
├── 2D Platformer / Arcade / Puzzle
│   ├── Web distribution → Phaser, PixiJS
│   └── Native distribution → Godot, Unity
│
├── 3D Action / Adventure
│   ├── AAA quality → Unreal
│   └── Cross-platform → Unity, Godot
│
├── Mobile Game
│   ├── Simple/Hyper-casual → Godot, Unity
│   └── Complex/3D → Unity
│
├── VR/AR Experience
│   └── Unity XR, Unreal VR, WebXR
│
└── Multiplayer
    ├── Real-time action → Dedicated server
    └── Turn-based → Client-server or P2P

Engine Selection Principles

Factor Unity Godot Unreal
Best for Cross-platform, mobile Indies, 2D, open source AAA, realistic graphics
Learning curve Medium Low High
2D support Good Excellent Limited
3D quality Good Good Excellent
Cost Free tier, then revenue share Free forever 5% after $1M
Team size Any Solo to medium Medium to large

Selection Questions

  1. What's the target platform?
  2. 2D or 3D?
  3. Team size and experience?
  4. Budget constraints?
  5. Required visual quality?

Core Game Development Principles

Game Loop

Every game has this cycle:
1. Input → Read player actions
2. Update → Process game logic
3. Render → Draw the frame

Performance Targets

Platform Target FPS Frame Budget
PC 60-144 6.9-16.67ms
Console 30-60 16.67-33.33ms
Mobile 30-60 16.67-33.33ms
Web 60 16.67ms
VR 90 11.11ms

Read the full file on GitHub · 164 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. yesterday First seen · 164 lines · 59 tokens per session scan A 0fc2a2593358

Subscribe to this mod's changes

game-developer is an agent published in the GitHub repository felipeslo/opencode-kit (2 stars, last pushed 5mo ago), licensed MIT. It adds 59 tokens to every session and 1,083 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to game-developer, differing in 13 lines, and is treated as a copy.

Related

Other agents, from other repositories