prp-spike

prp-spike is a skill for Claude Code, Codex from Wirasm/prp. It costs 141 tokens per session (3,419 once invoked), scanned A, original, MIT.

A proof-of-concept workflow for answering one testable question with a small throwaway build in a separate worktree. It ends with a PROVEN, DISPROVEN, or CONDITIONAL verdict based on evidence, not production code.

In plain words
What is it for?
Use it to test feasibility, compare approaches, or investigate what would be needed to make an idea possible.
Why use it?
It prevents teams from spending time planning or building an idea before checking whether it is feasible, suitable, or worth the required trade-offs.

Skill for Claude CodeCodex

About the project

PRP is a collection of prompts and workflows for AI-assisted software development with Claude Code. Its Product Requirement Prompts combine product requirements, selected codebase context, and an execution runbook so a coding agent can implement a vertical slice of software. The catalogue entries are the project’s own skills, agents, instructions, hook, and plugin workflows.

Wirasm/prp · 2,241 stars · on GitHub

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/wirasm/prp/prp-spike
Any agent
npx skills add Wirasm/prp --skill prp-spike
Clone the repo
git clone --depth 1 https://github.com/Wirasm/prp

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 prp-spike

README.md
[![agentmods](https://agentmods.dev/badge/skills/wirasm/prp/prp-spike.svg)](https://agentmods.dev/skills/wirasm/prp/prp-spike)
Your own site
<a href="https://agentmods.dev/skills/wirasm/prp/prp-spike"><img src="https://agentmods.dev/badge/skills/wirasm/prp/prp-spike.svg" alt="Measured on agentmods" height="20"></a>
Per session 141 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,419 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 $0.00141 $0.03419
Opus 5 $0.00071 $0.01709
Sonnet 5 $0.00028 $0.00684
Haiku 4.5 $0.00014 $0.00342

Measured 5d ago against content hash 7bab7d9841a2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prp-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 5d 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.

.agents/skills/prp-spike/SKILL.md · 166 lines

How it starts

The opening of the file, as written. The whole thing — 166 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Arguments: $ARGUMENTS (and $1, $2, ...) refer to the arguments given when this skill was invoked. Take them from the user's request; if absent, infer them from the conversation.

PRP Spike — Prove or Disprove

Settle an open question by building the smallest thing that could prove it wrong. The deliverable is a verdict backed by evidence, not shippable code.

Input: $ARGUMENTS (if absent, take the question from the conversation).

When to use

  • Feasibility — can this be built at all, here, with what we have?
  • Fit — does this sit naturally in our stack, or fight it the whole way?
  • Cost of admission — what would have to change (a primitive, an abstraction, a product constraint) to make it possible, and is that trade worth it?
  • Choice — which of several approaches survives contact with the real constraints?

Not for work whose feasibility is already settled — that is prp-plan then prp-implement. Not for something already broken — that is prp-debug.

The contract

  1. A spike answers one falsifiable question — or several sub-claims that share a single falsifier. No falsifiable question, no spike.
  2. Kill criteria are written before the build. Deciding what counts as failure after seeing results turns a spike into a rationalization.
  3. DISPROVEN is a success. It bought a decision with evidence and closed a path that would otherwise have cost weeks.
  4. Spike code is throwaway by construction and never opens a PR.

Phase 1 — Frame

Convert the request into a claim that can fail, and fix the kill criteria before touching code.

Reconnaissance before framing is allowed, and usually required. A hypothesis that names a version, a field, a threshold, or a mechanism cannot be written cold — read the issue, the source, and the environment until the claim can be stated precisely. The line is the falsifier: never let findings produced by the thing built to test the claim reshape the claim. Recon sharpens the question; results must only answer it.

Read the full file on GitHub · 166 lines

Files

What ships with it

4 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. 5d ago First seen · 166 lines · 141 tokens per session scan A 7bab7d9841a2

Subscribe to this mod's changes

prp-spike is a skill published in the GitHub repository Wirasm/prp (2,241 stars, last pushed 3d ago), licensed MIT. It adds 141 tokens to every session and 3,419 once invoked, about $0.0007 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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