ring:writing-prds

ring:writing-prds is a skill for Claude Code, Codex from LerianStudio/ring. It costs 102 tokens per session (1,092 once invoked), scanned A, original, Apache-2.0.

A Product Requirements Document, or PRD, that states what a product change should do, why it matters, what is included, and how to tell when it is complete.

In plain words
What is it for?
Use it to define a new product or major feature with clear scope, requirements, and testable acceptance criteria.
Why use it?
It separates user and product requirements from technical implementation choices, so the team agrees on the goal before deciding how to build it.

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/lerianstudio/ring/writing-prds
Any agent
npx skills add LerianStudio/ring --skill writing-prds
Clone the repo
git clone --depth 1 https://github.com/LerianStudio/ring

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 ring:writing-prds

README.md
[![agentmods](https://agentmods.dev/badge/skills/lerianstudio/ring/writing-prds.svg)](https://agentmods.dev/skills/lerianstudio/ring/writing-prds)
Your own site
<a href="https://agentmods.dev/skills/lerianstudio/ring/writing-prds"><img src="https://agentmods.dev/badge/skills/lerianstudio/ring/writing-prds.svg" alt="Measured on agentmods" height="20"></a>
Per session 102 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,092 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00102 $0.01092
Opus 5 $0.00051 $0.00546
Sonnet 5 $0.00020 $0.00218
Haiku 4.5 $0.00010 $0.00109

Measured 2d ago against content hash 23ea8c64de97, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ring:writing-prds 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 2d 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.

pm-team/skills/writing-prds/SKILL.md · 103 lines

How it starts

The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PRD Creation — WHAT and WHY Before HOW

When to use

  • Starting new product or major feature
  • User asks to "plan", "design", or "architect"
  • About to write code without documented requirements
  • Asked to create PRD or requirements document

Skip when

  • PRD already exists and validated → proceed to next gate
  • Pure technical task without product impact → TRD directly
  • Bug fix → systematic-debugging

Sequence

Runs after: ring:researching-features (Gate 0) Runs before: ring:mapping-feature-relationships (Gate 2, Large track) or ring:writing-trds (Gate 2, Small track)

The PRD is a squad-facing explanation of the product/feature being built: what it does, why it exists, what is in and out of scope, and how the squad knows it's done. It never answers HOW to build it (that's TRD) or WHERE components will live.

Mandatory Workflow

Phase Activities
0. Load Research Check docs/pre-dev/{feature}/research.md; reference codebase patterns and findings with file:line notation
1. Problem Definition State the problem without solution bias; explain why it matters now; cite evidence from research.md
2. Requirements Executive summary (3 sentences); functional requirements (WHAT the feature does); testable acceptance criteria per requirement; explicit scope boundaries (in/out)
3. Gate 1 Validation Problem articulated; requirements address problem; acceptance criteria testable; scope explicit; zero technology content

Include in PRD

  • Problem definition and why it matters
  • Feature description: what it does, observable behavior
  • Functional requirements (WHAT not HOW)
  • Acceptance criteria (testable, per requirement)
  • Scope boundaries (in/out explicitly)

Never Include in PRD

  • Architecture diagrams or component design
  • Technology choices (languages, frameworks, databases)
  • Implementation approaches or algorithms
  • Database schemas or API specifications
  • Code examples or package dependencies
  • Infrastructure needs or deployment strategies
  • Personas, demographics, market analysis, go-to-market plans
  • Adoption/satisfaction KPIs or business metric targets

Read the full file on GitHub · 103 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. 2d ago First seen · 103 lines · 102 tokens per session scan A 23ea8c64de97

Subscribe to this mod's changes

ring:writing-prds is a skill published in the GitHub repository LerianStudio/ring (211 stars, last pushed 16d ago), licensed Apache-2.0. It adds 102 tokens to every session and 1,092 once invoked, about $0.0005 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 2026-09-03.