c31-validate

c31-validate is a skill for Claude Code, Codex from ChianW/C31. It costs 70 tokens per session (927 once invoked), scanned A, a copy of validate-idea, MIT.

A guided method for testing whether a business idea is worth pursuing before building it. It uses a minimalist entrepreneur approach, including defining a specific problem and trying to sell a manual version first.

In plain words
What is it for?
Clarifying who has a problem, narrowing an idea to one audience, testing willingness to pay, and deciding whether to build.
Why use it?
It helps avoid spending months building a product that nobody wants by checking demand with real potential customers first.

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/chianw/c31/c31-validate
Any agent
npx skills add ChianW/C31 --skill c31-validate
Clone the repo
git clone --depth 1 https://github.com/ChianW/C31

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 c31-validate

README.md
[![agentmods](https://agentmods.dev/badge/skills/chianw/c31/c31-validate.svg)](https://agentmods.dev/skills/chianw/c31/c31-validate)
Your own site
<a href="https://agentmods.dev/skills/chianw/c31/c31-validate"><img src="https://agentmods.dev/badge/skills/chianw/c31/c31-validate.svg" alt="Measured on agentmods" height="20"></a>
Per session 70 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 927 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 86% copy Near-identical to another mod 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 $0.00070 $0.00927
Opus 5 $0.00035 $0.00464
Sonnet 5 $0.00014 $0.00185
Haiku 4.5 $0.00007 $0.00093

Measured 4d ago against content hash a2d3045ccb66, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

c31-validate 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 4d 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.

Origin

This is a copy

86% identical to validate-idea — 31 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/product/c31-validate/SKILL.md · 90 lines

How it starts

The opening of the file, as written. The whole thing — 90 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Multilingual Triggers

Language Trigger phrases
EN c31-validate
ZH 验证想法, 这个想法可行吗
JA アイデアを検証する, 実現可能か

Output language: Respond automatically in the user's conversation language.

Minimalist Entrepreneur — Idea Validator

Channel the philosophy of The Minimalist Entrepreneur by Sahil Lavingia. Help the user validate their business idea before they write a single line of code or spend a dollar.

Core Principle

Validation happens through selling, not building. Most founders spend months building a product nobody wants. Instead, validate by selling a manual version of your solution first.

Real-World Example: chian.io

Chian's ideas often emerge at the intersection of multiple projects (investment OS, podcast, mastermind). When validating, check whether the idea serves ONE community clearly, or if it's a "portfolio project" that needs to be scoped down to a single monetizable unit.

The Minimalist Validation Process

Step 1: Define the Problem (not the solution)

Ask the user:

  • Who specifically has this problem? (Be precise — not "businesses" but "freelance graphic designers who struggle with invoicing")
  • How are they solving it today? (The current workaround is your real competition)
  • How painful is this problem? (Mild annoyance vs. hair-on-fire)
  • Would they pay to make this problem go away?

Step 2: Can You Solve It Manually First?

Before building anything, can you solve this problem for people by hand?

  • Sahil calls this "processizing" — creating a manual valuable process
  • Do it yourself first. Hire yourself. Write down every step on a piece of paper
  • If you can solve it manually for a few people, you can eventually automate it
  • Example: Gumroad started as Sahil manually collecting PayPal info and paying creators one by one

Step 3: Will People Pay?

The ultimate validation is a transaction. Ask:

  • Can you charge for this manual service right now?
  • Have you talked to at least 10 potential customers?
  • Have at least 3 of them said they'd pay (or actually paid)?
  • What price point feels natural?

Read the full file on GitHub · 90 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. 4d ago First seen · 90 lines · 70 tokens per session scan A a2d3045ccb66

Subscribe to this mod's changes

c31-validate is a skill published in the GitHub repository ChianW/C31 (1 stars, last pushed 9d ago), licensed MIT. It adds 70 tokens to every session and 927 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 86% identical to validate-idea, differing in 31 lines, and is treated as a copy.

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