prototype

A method for making temporary prototypes to answer questions about a user interface, application state, or business logic before building production code.

In plain words
What is it for?
Use it to explore layouts, interaction flows, navigation, state changes, validation, data transformations, edge cases, or algorithms.
Why use it?
It lets a team test an idea, compare options, and clarify uncertain behavior without committing experimental code to the finished product.

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/setrathexx/codex-engineering-workflow-pack/prototype
Any agent
npx skills add SetraTheXX/Codex-Engineering-Workflow-Pack --skill prototype
Clone the repo
git clone --depth 1 https://github.com/SetraTheXX/Codex-Engineering-Workflow-Pack

Made for: Claude Code, Codex.

Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 881 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 $0.00049 $0.00881
Opus 5 $0.00024 $0.00441
Sonnet 5 $0.00010 $0.00176
Haiku 4.5 $0.00005 $0.00088

Measured yesterday against content hash 579c03438ce6, 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.

.agents/skills/prototype/SKILL.md · 176 lines

How it starts

The opening of the file, as written. The whole thing — 176 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prototype

Use a prototype to answer a question quickly before changing production behavior.

A prototype is temporary. It should have a clear question, success criteria, and exit decision.

Read First

Inspect relevant context:

  • docs/agents/domain.md
  • docs/agents/test-commands.md
  • CONTEXT.md
  • relevant ADRs under docs/adr/
  • existing UI routes, components, modules, tests, or scripts near the idea

If setup docs are missing, infer local conventions from the repo and say what is unknown.

Choose Prototype Type

Pick one:

Logic Prototype

Use when the question is about:

  • state transitions,
  • business rules,
  • validation behavior,
  • data transformations,
  • edge cases,
  • algorithm shape.

Typical shape: a small local script, REPL-friendly module, or isolated route through existing public functions.

UI Prototype

Use when the question is about:

  • layout,
  • interaction flow,
  • component composition,
  • navigation,
  • visual variants,
  • user feedback states.

Typical shape: a temporary route, page, story, or local-only component variant.

If the type is ambiguous, recommend one and explain why.

Workflow

1. Define The Experiment

State:

  • question being answered,
  • prototype type,
  • audience or actor,
  • success criteria,
  • constraints,
  • what will not be tested.

If success criteria are unclear, ask the user before creating files.

2. Inspect Local Conventions

Find where a temporary prototype would fit without confusing production code.

Look for:

  • existing scripts,
  • playground routes,
  • storybook stories,
  • examples directories,
  • test fixtures,
  • local-only dev pages.

Do not invent a new convention when the repo already has one.

3. Propose Path And Command

Before writing, propose:

  • files to create,
  • files to touch,
  • how to run it,
  • how it will be marked temporary,
  • how it will be removed or promoted.

Ask for approval before creating files.

4. Build Small

When approved:

  • keep state local unless persistence is the experiment,
  • avoid production integration by default,
  • mark temporary files clearly,
  • expose relevant state in the UI or console,
  • skip polish that does not answer the question,
  • avoid new dependencies unless approved.

Read the full file on GitHub · 176 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 176 lines · 49 tokens per session scan A 579c03438ce6

Subscribe to this mod's changes

prototype is a skill published in the GitHub repository SetraTheXX/Codex-Engineering-Workflow-Pack (1 stars, last pushed yesterday), licensed MIT. It adds 49 tokens to every session and 881 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 2026-08-31.

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