prototype

prototype is a skill for Claude Code, Codex from TraftG/opencode-game-studio. It costs 31 tokens per session (774 once invoked), scanned A, original, MIT.

A rapid prototyping workflow for testing whether a game concept or mechanic is worth pursuing. A prototype is a small, temporary implementation made to answer one focused question.

In plain words
What is it for?
Use it to define a prototype question, build an isolated test with compatible tools, run it, and produce a structured prototype report.
Why use it?
It lets a team test the central idea quickly without requiring production-quality code or complete game content.

Skill for Claude CodeCodex

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 skills/traftg/opencode-game-studio/prototype
Any agent
npx skills add TraftG/opencode-game-studio --skill prototype
Clone the repo
git clone --depth 1 https://github.com/TraftG/opencode-game-studio

Made for: Claude Code, Codex.

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 prototype

README.md
[![agentmods](https://agentmods.dev/badge/skills/traftg/opencode-game-studio/prototype.svg)](https://agentmods.dev/skills/traftg/opencode-game-studio/prototype)
Your own site
<a href="https://agentmods.dev/skills/traftg/opencode-game-studio/prototype"><img src="https://agentmods.dev/badge/skills/traftg/opencode-game-studio/prototype.svg" alt="Measured on agentmods" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 774 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 $0.00031 $0.00774
Opus 5 $0.00015 $0.00387
Sonnet 5 $0.00006 $0.00155
Haiku 4.5 $0.00003 $0.00077

Measured yesterday against content hash 71dc38c108bc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prototype 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

Copies of this mod

2 near-identical copies found in the catalogue:

.opencode/skills/prototype/SKILL.md · 100 lines

What it actually says

When this skill is invoked:

  1. Read the concept description from the argument. Identify the core question this prototype must answer. If the concept is vague, state the question explicitly before proceeding.

  2. Read OPENCODE.md for project context and the current tech stack. Understand what engine, language, and frameworks are in use so the prototype is built with compatible tooling.

  3. Create a prototype plan: Define in 3-5 bullet points what the minimum viable prototype looks like. What is the core question? What is the absolute minimum code needed to answer it? What can be skipped?

  4. Create the prototype directory: prototypes/[concept-name]/ where [concept-name] is a short, kebab-case identifier derived from the concept.

  5. Implement the prototype in the isolated directory. Every file must begin with:

    // PROTOTYPE - NOT FOR PRODUCTION
    // Question: [Core question being tested]
    // Date: [Current date]
    

    Standards are intentionally relaxed:

    • Hardcode values freely
    • Use placeholder assets
    • Skip error handling
    • Use the simplest approach that works
    • Copy code rather than importing from production
  6. Test the concept: Run the prototype. Observe behavior. Collect any measurable data (frame times, interaction counts, feel assessments).

  7. Generate the Prototype Report and save it to prototypes/[concept-name]/REPORT.md:

## Prototype Report: [Concept Name]

### Hypothesis
[What we expected to be true -- the question we set out to answer]

### Approach
[What we built, how long it took, what shortcuts we took]

### Result
[What actually happened -- specific observations, not opinions]

### Metrics
[Any measurable data collected during testing]
- Frame time: [if relevant]
- Feel assessment: [subjective but specific -- "response felt sluggish at
  200ms delay" not "felt bad"]
- Player action counts: [if relevant]
- Iteration count: [how many attempts to get it working]

### Recommendation: [PROCEED / PIVOT / KILL]

[One paragraph explaining the recommendation with evidence]

### If Proceeding
[What needs to change for a production-quality implementation]
- Architecture requirements
- Performance targets
- Scope adjustments from the original design
- Estimated production effort

### If Pivoting
[What alternative direction the results suggest]

### If Killing
[Why this concept does not work and what we should do instead]

### Lessons Learned
[Discoveries that affect other systems or future work]
  1. Output a summary to the user with: the core question, the result, and the recommendation. Link to the full report at prototypes/[concept-name]/REPORT.md.

Important Constraints

  • Prototype code must NEVER import from production source files
  • Production code must NEVER import from prototype directories
  • If the recommendation is PROCEED, the production implementation must be written from scratch -- prototype code is not refactored into production
  • Total prototype effort should be timeboxed to 1-3 days equivalent of work
  • If the prototype scope starts growing, stop and reassess whether the question can be simplified
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 · 100 lines · 31 tokens per session scan A 71dc38c108bc

Subscribe to this mod's changes

prototype is a skill published in the GitHub repository TraftG/opencode-game-studio (38 stars, last pushed 4mo ago), licensed MIT. It adds 31 tokens to every session and 774 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 2026-09-03.

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