prototype-guide

A guide for creating self-contained HTML prototypes to test product ideas. It uses project design rules, user descriptions, the specific hypothesis being tested, and the product vision, while keeping the prototype openable directly in a browser.

In plain words
What is it for?
Use it to create single-file prototypes, test usability or value hypotheses, and make proposed product flows tangible for evaluation.
Why use it?
It gives a prototype enough context to test the intended user flow without building the full product. Using mock data keeps the test focused on usability and value rather than real integrations.

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/shinpr/claude-code-discover/prototype-guide
Any agent
npx skills add shinpr/claude-code-discover --skill prototype-guide
Clone the repo
git clone --depth 1 https://github.com/shinpr/claude-code-discover

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 801 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 $0.00801
Opus 5 $0.00024 $0.00400
Sonnet 5 $0.00010 $0.00160
Haiku 4.5 $0.00005 $0.00080

Measured 2d ago against content hash 9f4bc1d33207, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prototype-guide 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 2d 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/prototype-guide/SKILL.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prototype Generation Guide

Purpose

Prototypes are hypothesis validation tools, not final implementations. They test Usability and Value risks by making ideas tangible enough for evaluation.

Output Format

Generate a single self-contained HTML file in docs/discovery/prototypes/. The file must:

  • Open directly in a browser (double-click) with no build step
  • Include all CSS and JavaScript inline
  • Use mock data instead of real APIs

Choose the smallest browser-native implementation that makes the validation boundary observable. Use an external CSS or font resource only when a supplied design decision requires it and the prototype remains directly openable; a library choice is not part of the validation outcome.

Design Context Injection

Before generating, read the target hypothesis and the source artifacts whose decisions can change the tested flow:

  1. Design Principles — read docs/product/design-principles.md
  2. Persona — read relevant file from docs/product/personas/
  3. Hypothesis Under Test — read the target hypothesis file from docs/discovery/hypotheses/
  4. Vision — read docs/product/vision.md for tone and value proposition

Prefer these canonical paths but accept equivalent supplied evidence. Use their content directly, represent missing decision-relevant evidence as unknown, and inspect another artifact only when it can change the tested interaction.

Blueprint Context (include when docs/product/design/ exists)

Read only artifacts from docs/product/design/ that can change the tested navigation, entities, flow, interaction, or visual direction. When present and relevant, an approved brand decision overrides ad-hoc aesthetic inference.

Additional Context (include when available)

  1. State Design — which states to demonstrate (Loading / Empty / Error / Partial / Success)
  2. Accessibility Requirements — WCAG 2.2 AA baseline
  3. Existing Components — use codebase-analyzer to identify reusable components if a codebase exists
  4. Journey Position — where in the user journey this interaction occurs

Read the full file on GitHub · 65 lines

Files

What ships with it

1 file 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. 2d ago First seen · 65 lines · 49 tokens per session scan A 9f4bc1d33207

Subscribe to this mod's changes

prototype-guide is a skill published in the GitHub repository shinpr/claude-code-discover (10 stars, last pushed 4d ago), licensed MIT. It adds 49 tokens to every session and 801 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.

Related

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