prototype

A disposable, runnable piece of code used to answer an unclear logic, state, workflow, or interface question quickly.

In plain words
What is it for?
Use it to try interface directions, explore state machines, test workflows, or validate a design question with a small local example.
Why use it?
It makes uncertain designs easier to test and compare without committing to production code before the idea is understood.

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/drvoss/everything-copilot-cli/prototype
Any agent
npx skills add drvoss/everything-copilot-cli --skill prototype
Clone the repo
git clone --depth 1 https://github.com/drvoss/everything-copilot-cli

Made for: Claude Code, Codex.

Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,023 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 $0.00039 $0.01023
Opus 5 $0.00019 $0.00511
Sonnet 5 $0.00008 $0.00205
Haiku 4.5 $0.00004 $0.00102

Measured 3d ago against content hash fe732815d8a3, 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 3d 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.

skills/development/prototype/SKILL.md · 128 lines

How it starts

The opening of the file, as written. The whole thing — 128 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prototype

A prototype is disposable code that answers a question faster than debate. Keep it close to the real area, make it easy to run, and optimize for learning rather than polish.

When to Use

  • The user says "prototype this", "try a few designs", or "let me play with it"
  • A state model or workflow is hard to reason about on paper
  • You need several UI directions before picking one
  • The fastest way to answer the question is to build a small runnable artifact

When NOT to Use

Instead of prototype Use
You are building production-ready functionality spec-driven-development
The main problem is root-cause analysis of broken code diagnose
You already know the design and need safe cleanup refactor-clean

Prerequisites

  • A concrete question the prototype should answer
  • A place near the target code where throwaway work can live temporarily
  • One obvious command the user can run locally

Workflow

1. Choose the branch

Decide which question you are answering:

  • Logic / state question — build a tiny runnable terminal or script-based prototype that pushes the state machine through the tricky cases
  • UI question — build several clearly different visual variants that can be switched from one route, page, or entry point

If the question is ambiguous and the user is unavailable, match the surrounding code and state the assumption clearly at the top.

2. Mark it as throwaway from day one

Put the prototype near the feature it informs, but name it so nobody confuses it with production code. Follow the project's existing routing or directory conventions instead of inventing a brand-new top-level structure.

3. Make it runnable with one command

Use the project's existing runtime:

  • npm run prototype:checkout
  • python src\feature\prototype.py
  • go run .\cmd\prototype

The user should not need a multi-step setup just to learn from the prototype.

Read the full file on GitHub · 128 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. 3d ago First seen · 128 lines · 39 tokens per session scan A fe732815d8a3

Subscribe to this mod's changes

prototype is a skill published in the GitHub repository drvoss/everything-copilot-cli (45 stars, last pushed 6d ago), licensed MIT. It adds 39 tokens to every session and 1,023 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.

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