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.
npx agentmods add skills/buildgreatproducts/builder-os/idea-validatornpx skills add BuildGreatProducts/builder-os --skill idea-validatorgit clone --depth 1 https://github.com/BuildGreatProducts/builder-osWrote 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.
[](https://agentmods.dev/skills/buildgreatproducts/builder-os/idea-validator)<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="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00128 | $0.03513 |
| Opus 5 | $0.00064 | $0.01757 |
| Sonnet 5 | $0.00026 | $0.00703 |
| Haiku 4.5 | $0.00013 | $0.00351 |
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 6d 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.
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):
- Read the file.
- Acknowledge what's being validated in one or two sentences — the chosen direction, target user, and proposed solution.
- Ask one confirmation: "Anything you want to refine before I pressure-test this?" Make any edits the founder requests, then run validation.
- 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.
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.
- 6d ago First seen · 322 lines · 128 tokens per session scan A 95d876b7ed70
idea-validator is a skill published in the GitHub repository BuildGreatProducts/builder-os (217 stars, last pushed 2mo ago), licensed MIT. It adds 128 tokens to every session and 3,513 once invoked, about $0.0006 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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