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 skills add davekilleen/Dex --skill product-briefgit clone --depth 1 https://github.com/davekilleen/DexWrote 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/davekilleen/dex/product-brief)<a href="https://agentmods.dev/skills/davekilleen/dex/product-brief"><img src="https://agentmods.dev/badge/skills/davekilleen/dex/product-brief/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.
<a href="https://agentmods.dev/skills/davekilleen/dex/product-brief"><img src="https://agentmods.dev/badge/skills/davekilleen/dex/product-brief.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00075 | $0.04313 |
| Opus 5.5 | $0.00030 | $0.01725 |
| Sonnet 5.5 | $0.00015 | $0.00863 |
| Haiku 4.5 | $0.00007 | $0.00431 |
Grade A, and why
product-brief 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.
How it starts
The opening of the file, as written. The whole thing — 817 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Purpose
Extract product ideas from your head through guided questioning, then generate a detailed Product Requirements Document (PRD). Designed for product people who have a vision but need help articulating it clearly.
The Problem This Solves
You have an idea for a product or feature in your mind, but struggle to explain it comprehensively. This command acts as your product thought partner — asking the right questions to extract what you're envisioning, then structuring it into a PRD ready for a team to execute.
Usage
/product-brief [initial idea]
Examples:
/product-brief Add a notification system to our app/product-brief Build a customer feedback portal/product-brief Create an onboarding flow for new users/product-brief(prompts you for the idea)
Process Flow
Phase 1: Capture Initial Idea
If no idea is provided: Ask: "What product or feature are you thinking about?"
- Wait for their description (1 sentence to several paragraphs)
- Capture it as the starting point
If idea is provided: Start with whatever the user provides:
- Could be 1 sentence or 5 paragraphs
- Capture it as the starting point
- Don't judge, just absorb
Display:
## Initial Idea
[User's description]
---
**Next:** I'll ask a few questions to understand this better.
Phase 2: Clarifying Questions (Conversational)
Important: Ask questions conversationally, not as a survey. 2-3 questions at a time, then wait for answers before asking more.
Question Strategy:
Round 1 (Critical Context):
- What problem does this solve?
- Who is this for?
- What success looks like?
Round 2 (Constraints & Scope): Based on Round 1 answers, ask about:
- Timeline expectations
- Technical constraints
- Existing systems to integrate with
- What's explicitly out of scope
Round 3 (User Experience):
- How do users discover this?
- What's the core user journey?
- What actions should be easy vs hard?
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.
- 1mo ago Changed 778fbbfd86ac
- 1mo ago First seen · 817 lines · 75 tokens per session scan A 7658ed45148e
product-brief is a skill published in the GitHub repository davekilleen/Dex (508 stars, last pushed 2d ago), licensed MIT. It adds 75 tokens to every session and 4,313 once invoked, about $0.0003 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 2026-09-03.
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