What is prd-writing-guide?

A guide for writing complete product requirements documents (PRDs), which describe what a product must do so a development team can build it without repeated clarification. It provides discovery methods, documentation structure, completeness checks, and advice on common gaps.

Use it to write a new PRD, review an existing draft, check whether requirements are complete, and prepare documentation for a later engineering-specification process.

It turns vague product ideas into requirements that developers can implement and verify. This reduces missing decisions, conflicting interpretations, and rework during development.

prd-writing-guide — Skill for Claude Code and Codex by okwinds

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 okwinds/miscellany --skill prd-writing-guide

Clone the repo

git clone --depth 1 https://github.com/okwinds/miscellany

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/okwinds/miscellany/prd-writing-guide/github.svg)](https://agentmods.dev/skills/okwinds/miscellany/prd-writing-guide)

Your own site

<a href="https://agentmods.dev/skills/okwinds/miscellany/prd-writing-guide"><img src="https://agentmods.dev/badge/skills/okwinds/miscellany/prd-writing-guide/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/okwinds/miscellany/prd-writing-guide"><img src="https://agentmods.dev/badge/skills/okwinds/miscellany/prd-writing-guide.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 155 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,320 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.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00155	$0.04320
Opus 5.5	$0.00062	$0.01728
Sonnet 5.5	$0.00031	$0.00864
Haiku 4.5	$0.00015	$0.00432

Measured 2mo ago against content hash c34b873549e5, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

prd-writing-guide 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 2mo ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/generate_prd_skeleton.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

agent/skills/prd-writing-guide/SKILL.md · 535 lines

How it starts

The opening of the file, as written. The whole thing — 535 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PRD Writing Guide

Overview

Write PRDs so complete that development teams can implement the entire product without asking a single clarifying question.

Skill Workflow Context

This skill is part of a 3-skill pipeline:

┌─────────────────┐     ┌─────────────────┐     ┌─────────────────┐
│ prd-writing-    │────►│ prd-to-         │     │ reverse-        │
│ guide           │     │ engineering-    │     │ engineering-    │
│                 │     │ spec            │     │ spec            │
│ [THIS SKILL]    │     │ PRD→Eng Spec   │     │ Code→Spec       │
└─────────────────┘     └─────────────────┘     └─────────────────┘

For AI Agent products, use `ai-agent-prd` instead (which extends this skill).

Handoff contract: The PRD this skill produces must be complete enough to pass prd-to-engineering-spec's Phase 0 validation without any ❌ items.

The PRD Quality Test

┌─────────────────────────────────────────────────────────────────┐
│                     The Developer Test                          │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  Give your PRD to a developer who knows nothing about the      │
│  project. Can they:                                            │
│                                                                 │
│  □ Understand WHY we're building this?                         │
│  □ Know exactly WHAT to build (and what NOT to)?               │
│  □ Handle EVERY edge case without guessing?                    │
│  □ Write test cases for EVERY requirement?                     │
│  □ Estimate the work with confidence?                          │
│                                                                 │
│  If any answer is "no", your PRD is incomplete.                │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

Core Principle: Eliminate Ambiguity

Read the full file on GitHub · 535 lines

Files

What ships with it

12 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.

2mo ago First seen · 535 lines · 155 tokens per session scan A c34b873549e5

Subscribe to this mod's changes

prd-writing-guide is a skill published in the GitHub repository okwinds/miscellany (50 stars, last pushed 5mo ago), licensed MIT. It adds 155 tokens to every session and 4,320 once invoked, about $0.0006 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.

Planning Writing and docs

prd-writing-guide next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
prd-writing-guideokwinds/miscellany	Skill	50	5mo ago	MIT	A	155	Claude Code, Codex
imagegenopenai/codex	Skill	133k	yesterday	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	yesterday	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	4d ago	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	313k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	103	Claude Code