idea-validator

idea-validator is a skill for Claude Code, Codex from BuildGreatProducts/builder-os. It costs 128 tokens per session (3,513 once invoked), scanned A, original, MIT.

A product-idea review that checks whether a proposed product solves a real problem before work begins. It examines flaws, alternatives people already use, potential early customers, and a small test.

In plain words
What is it for?
Use it to assess an idea, understand current competition and customer behavior, plan outreach to the first 10 customers, and define a two-week MVP test. An MVP is the smallest version used to learn whether the idea works.
Why use it?
It helps founders avoid spending time and money on ideas that people may not need. It replaces assumptions with a quick test and a clear strong, weak, or change-direction verdict.

Skill for Claude CodeCodex

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

not rated 231repo +1 3mo ago A scan Socket: passSnyk: passSkillSpector: pass 128 tokens original MIT

Good fit Use it to assess an idea, understand current competition and customer behavior, plan outreach to the first 10 customers, and define a two-week MVP test. An MVP is the smallest version used to learn whether the idea works.

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Install with agentmods
npx agentmods add skills/buildgreatproducts/builder-os/idea-validator
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 BuildGreatProducts/builder-os --skill idea-validator
Clone the repo
git clone --depth 1 https://github.com/BuildGreatProducts/builder-os

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 idea-validator

README.md
[![agentmods](https://agentmods.dev/badge/skills/buildgreatproducts/builder-os/idea-validator/github.svg)](https://agentmods.dev/skills/buildgreatproducts/builder-os/idea-validator)
Your own site
<a href="https://agentmods.dev/skills/buildgreatproducts/builder-os/idea-validator"><img src="https://agentmods.dev/badge/skills/buildgreatproducts/builder-os/idea-validator/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 idea-validator

Your own site · 80×15
<a href="https://agentmods.dev/skills/buildgreatproducts/builder-os/idea-validator"><img src="https://agentmods.dev/badge/skills/buildgreatproducts/builder-os/idea-validator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,513 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. Third-party audits
  • Socket pass 16 Jun 2026
  • Snyk pass 16 Jun 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00128 $0.03513
Opus 5.5 $0.00051 $0.01405
Sonnet 5.5 $0.00026 $0.00703
Haiku 4.5 $0.00013 $0.00351

Measured 1mo ago against content hash 95d876b7ed70, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

idea-validator 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 1mo 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/idea-validator/SKILL.md · 322 lines

How it starts

The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Validate — Pressure-Test the Idea

This skill pressure-tests a product idea before the founder invests in planning, building, or launching. It surfaces fatal flaws, tests whether the problem is real, maps actual competition (including current behavior), defines the smallest 2-week MVP test, and returns a direct strong / weak / pivot verdict.

The Idea Validator sits between the Idea Generator and Product Planner skills in the BuilderOS pipeline. It also runs fully standalone — if no docs/product-idea.md exists, it gathers the minimum input itself and writes a fresh docs/product-idea.md after a strong or pivot verdict.

Shared Context

You are a product development advisor. You are warm, direct, and opinionated. You treat the founder as capable and smart — you're here to help them articulate what's already in their head, not to lecture them.

Resumability: This skill is designed to be interrupted and resumed. Always check the current project state before starting work — does docs/validation-report.md already exist? Has docs/product-idea.md been edited since the last run? Pick up from where things left off rather than restarting.

Modes

Validate runs one mode: a full diagnosis. Every run produces the complete report (verdict, scorecard, core assumption, fatal flaws, problem reality, competition, first 10 customers, MVP). No mode flag, no mode selection.

Entry Paths

docs/product-idea.md exists (the common path after Idea):

  1. Read the file.
  2. Acknowledge what's being validated in one or two sentences — the chosen direction, target user, and proposed solution.
  3. Ask one confirmation: "Anything you want to refine before I pressure-test this?" Make any edits the founder requests, then run validation.
  4. Skip to Step 1 below.

No docs/product-idea.md (standalone use): Open with:

"Send me the startup idea, target customer, and what you want them to do or pay for."

Wait for the response. If any of the three are missing or vague, ask once for the missing piece. Do not run a full intake — Validate is not Idea. Three sentences of context is enough to begin. Then run Step 1.

Read the full file on GitHub · 322 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. 1mo ago First seen · 322 lines · 128 tokens per session scan A 95d876b7ed70

Subscribe to this mod's changes

idea-validator is a skill published in the GitHub repository BuildGreatProducts/builder-os (231 stars, last pushed 3mo ago), licensed MIT. It adds 128 tokens to every session and 3,513 once invoked, about $0.0005 per session on Opus 5.5. 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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