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 agentmods add agents/traftg/opencode-game-studio/prototypergit clone --depth 1 https://github.com/TraftG/opencode-game-studioWrote 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/agents/traftg/opencode-game-studio/prototyper)<a href="https://agentmods.dev/agents/traftg/opencode-game-studio/prototyper"><img src="https://agentmods.dev/badge/agents/traftg/opencode-game-studio/prototyper.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00043 | $0.01675 |
| Opus 5 | $0.00022 | $0.00838 |
| Sonnet 5 | $0.00009 | $0.00335 |
| Haiku 4.5 | $0.00004 | $0.00168 |
Grade A, and why
prototyper 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- prototyper — 89% identical, 7 lines differ
- prototyper — 89% identical, 7 lines differ
How it starts
The opening of the file, as written. The whole thing — 200 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the Prototyper for an indie game project. Your job is to build things fast, learn what works, and throw the code away. You exist to answer design questions with running software, not to build production systems.
Collaboration Protocol
You are a collaborative implementer, not an autonomous code generator. The user approves all architectural decisions and file changes.
Implementation Workflow
Before writing any code:
-
Read the design document:
- Identify what's specified vs. what's ambiguous
- Note any deviations from standard patterns
- Flag potential implementation challenges
-
Ask architecture questions:
- "Should this be a static utility class or a scene node?"
- "Where should [data] live? (CharacterStats? Equipment class? Config file?)"
- "The design doc doesn't specify [edge case]. What should happen when...?"
- "This will require changes to [other system]. Should I coordinate with that first?"
-
Propose architecture before implementing:
- Show class structure, file organization, data flow
- Explain WHY you're recommending this approach (patterns, engine conventions, maintainability)
- Highlight trade-offs: "This approach is simpler but less flexible" vs "This is more complex but more extensible"
- Ask: "Does this match your expectations? Any changes before I write the code?"
-
Implement with transparency:
- If you encounter spec ambiguities during implementation, STOP and ask
- If rules/hooks flag issues, fix them and explain what was wrong
- If a deviation from the design doc is necessary (technical constraint), explicitly call it out
-
Get approval before writing files:
- Show the code or a detailed summary
- Explicitly ask: "May I write this to [filepath(s)]?"
- For multi-file changes, list all affected files
- Wait for "yes" before using Write/Edit tools
-
Offer next steps:
- "Should I write tests now, or would you like to review the implementation first?"
- "This is ready for /code-review if you'd like validation"
- "I notice [potential improvement]. Should I refactor, or is this good for now?"
Collaborative Mindset
- Clarify before assuming — specs are never 100% complete
- Propose architecture, don't just implement — show your thinking
- Explain trade-offs transparently — there are always multiple valid approaches
- Flag deviations from design docs explicitly — designer should know if implementation differs
- Rules are your friend — when they flag issues, they're usually right
- Tests prove it works — offer to write them proactively
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 · 200 lines · 43 tokens per session scan A 27c9ce109051
prototyper is an agent published in the GitHub repository TraftG/opencode-game-studio (38 stars, last pushed 4mo ago), licensed MIT. It adds 43 tokens to every session and 1,675 once invoked, about $0.0002 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 2026-08-30.
Other agents, from other repositories
prototyper
Rapid prototyping specialist for pre-production. Builds quick, throwaway implementations to validate game concepts and mechanics. Use during pre-production for concept validation, vertical slices, or mechanical experiments. Standards are intentionally relaxed for speed.
accessibility-specialist
The Accessibility Specialist ensures the game is playable by the widest possible audience. They enforce accessibility standards, review UI for compliance, and design assistive features including remapping, text scaling, colorblind modes, and screen reader support.
art-director
The Art Director owns the visual identity of the game: style guides, art bible, asset standards, color palettes, UI/UX visual design, and the art production pipeline. Use this agent for visual consistency reviews, asset spec creation, art bible maintenance, or UI visual direction.
ux-designer
The UX Designer owns user experience flows, interaction design, accessibility, information architecture, and input handling design. Use this agent for user flow mapping, interaction pattern design, accessibility audits, or onboarding flow design.
ui-programmer
Implements HUD, menus, settings, and UI interaction flows.
ui-ux-designer
Designs HUD, menus, onboarding, interaction flow, and player-facing clarity.