prototype-spike

prototype-spike is a skill for Claude Code, Codex from stark-ai-de/agent-skills. It costs 56 tokens per session (590 once invoked), scanned A, original, Apache-2.0.

A process for building a small throwaway prototype to answer one design, API, user-interface, speed, or integration question before production work begins.

In plain words
What is it for?
Use it to define a hypothesis, build a bounded experiment, record its findings and limits, and either remove it or carry the proven idea into production.
Why use it?
It provides evidence for an uncertain decision while limiting the time, files, and dependencies that might otherwise become permanent.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to define a hypothesis, build a bounded experiment, record its findings and limits, and either remove it or carry the proven idea into production.

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Install with agentmods
npx agentmods add skills/stark-ai-de/agent-skills/prototype-spike
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.

Any agent
npx skills add stark-ai-de/agent-skills --skill prototype-spike
Clone the repo
git clone --depth 1 https://github.com/stark-ai-de/agent-skills

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-spike

README.md
[![agentmods](https://agentmods.dev/badge/skills/stark-ai-de/agent-skills/prototype-spike/github.svg)](https://agentmods.dev/skills/stark-ai-de/agent-skills/prototype-spike)
Your own site
<a href="https://agentmods.dev/skills/stark-ai-de/agent-skills/prototype-spike"><img src="https://agentmods.dev/badge/skills/stark-ai-de/agent-skills/prototype-spike/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for prototype-spike

Your own site · 80×15
<a href="https://agentmods.dev/skills/stark-ai-de/agent-skills/prototype-spike"><img src="https://agentmods.dev/badge/skills/stark-ai-de/agent-skills/prototype-spike.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 590 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00056 $0.00590
Opus 5 $0.00028 $0.00295
Sonnet 5 $0.00011 $0.00118
Haiku 4.5 $0.00006 $0.00059

Measured 9d ago against content hash 0cb3dca766ba, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

prototype-spike 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 9d 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.

incubator/skills/engineering-workflows/prototype-spike/SKILL.md · 84 lines

How it starts

The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prototype Spike

Goal

Answer a specific uncertainty with a deliberately bounded prototype, then either discard it or convert only the proven idea into production work.

When to use

  • The user asks for a spike, proof of concept, prototype, or throwaway experiment.
  • A design choice needs evidence before production implementation.
  • An integration, API, performance assumption, or UI interaction is uncertain.

When not to use

  • The user needs production-ready implementation now.
  • The uncertainty can be answered by reading docs or existing code.
  • The prototype would require secrets, real customer data, or irreversible operations.

Inputs to inspect

  • The exact question the prototype must answer.
  • Existing architecture, ADRs, validation commands, and domain docs.
  • Constraints on where prototype files may live and how they should be cleaned up.

Workflow

  1. State the hypothesis or design question.
  2. Define the prototype boundary, timebox, and throwaway location.
  3. Ask before adding dependencies, new services, or files outside an agreed scratch area.
  4. Build the smallest experiment that answers the question.
  5. Record findings, limitations, and production implications.
  6. Clean up throwaway files or clearly mark what should remain.
  7. Recommend whether to proceed, revise, or abandon the production approach.

Safety rules

  • Do not ship prototype code as production code without a review step.
  • Do not add persistent dependencies or config unless approved.
  • Do not use live credentials, customer data, or destructive operations in a spike.
  • Do not leave scratch files unmarked or unexplained.

References

No bundled references. Use local ADRs and domain docs when the spike tests an architectural assumption.

Scripts

No bundled scripts.

Output format

Return:

  1. Question or hypothesis
  2. Prototype boundary and files touched
  3. Evidence gathered
  4. Decision recommendation
  5. Cleanup performed or remaining
  6. Production follow-up tasks

Read the full file on GitHub · 84 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. 9d ago First seen · 84 lines · 56 tokens per session scan A 0cb3dca766ba

Subscribe to this mod's changes

prototype-spike is a skill published in the GitHub repository stark-ai-de/agent-skills (5 stars, last pushed today), licensed Apache-2.0. It adds 56 tokens to every session and 590 once invoked, about $0.0003 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.