prototype

A small throwaway program, called a spike, built to answer one design or technical question before committing to production code.

In plain words
What is it for?
Use it to test state logic, API behavior, difficult edge cases, or alternative user-interface directions.
Why use it?
It lets you test whether an approach works without spending time building the entire feature or treating experimental code as the final solution.

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/aethrox/doctrine/prototype
Any agent
npx skills add aethrox/doctrine --skill prototype
Clone the repo
git clone --depth 1 https://github.com/aethrox/doctrine

Made for: Claude Code, Codex.

Per session 59 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,054 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 $0.00059 $0.01054
Opus 5 $0.00030 $0.00527
Sonnet 5 $0.00012 $0.00211
Haiku 4.5 $0.00006 $0.00105

Measured 2d ago against content hash 09aa52a37e24, 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 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/SKILL.md · 50 lines

How it starts

The opening of the file, as written. The whole thing — 50 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Prototype

A spike solution (Kent Beck and Ward Cunningham's term from Extreme Programming) is a quick, throwaway program written to answer one specific technical question, ignoring every other concern. The code is not the deliverable; the answer is. Most spikes aren't good enough to keep, and that's by design: keeping one is a sign it wasn't actually a spike.

Phase 1: Name the question

Before writing anything, state the single question this spike exists to answer; "does this state machine handle the cancel-mid-submit case correctly?", "can this API return the shape we need without an extra round-trip?", "what should this settings panel look like?" A spike with more than one question attached is really two spikes; split it.

Identify which kind of question it is, since it decides the artifact:

  • "Does this logic / state model hold up?" → build a single shareable file (or minimal script) that drives the logic through the cases that are hard to reason about on paper, printing the resulting state after each step so the answer is visible, not inferred.
  • "What should this look like / feel like?" → build the UI variation(s) directly in the app's existing routing/component conventions, switchable without rebuilding, so it can be looked at rather than described.
  • "Will this technical approach even work?" → build the smallest possible harness that exercises the risky part end-to-end (the actual API call, the actual library, the actual integration point) and nothing else.

If the question is genuinely ambiguous and the user isn't reachable, default to whichever reading matches the surrounding code, and say so at the top of the spike rather than guessing silently.

Phase 2: Timebox it

A spike is a thin, deep drive at one unknown (the "spike through a log" the name comes from), not a general exploration. Set an explicit bound before starting (Beck's own spikes ran half a day to two days; cap at what the question actually needs) and stop when the question is answered, even if the code is ugly. A spike that's still running past its bound has usually stopped being a spike and turned into unplanned production work; surface that instead of continuing silently.

Read the full file on GitHub · 50 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 · 50 lines · 59 tokens per session scan A 09aa52a37e24

Subscribe to this mod's changes

prototype is a skill published in the GitHub repository aethrox/doctrine (18 stars, last pushed 20d ago), licensed MIT. It adds 59 tokens to every session and 1,054 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 2026-08-30.

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