authoring-prd

authoring-prd is a skill for Claude Code, Codex from HECer/yoke. It costs 27 tokens per session (577 once invoked), scanned A, original, MIT.

A guide for turning a product idea or change into a small, continuous backlog of implementable stories. Each story includes observable acceptance criteria and commands that verify the result.

In plain words
What is it for?
Use it to write or check a PRD, break work into dependent stories, define behavioural evidence, and set priorities.
Why use it?
It replaces vague requirements with buildable, testable work items and exposes unresolved planning decisions early.

Skill for Claude CodeCodex

Part of the yoke plugin — 34 skills, 1 hook shipped together

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/hecer/yoke/authoring-prd
Any agent
npx skills add HECer/yoke --skill authoring-prd
Clone the repo
git clone --depth 1 https://github.com/HECer/yoke

Made for: Claude Code, Codex.

Or install yoke, the plugin that ships this one along with the rest of its 34 skills, 1 hook.

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 authoring-prd

README.md
[![agentmods](https://agentmods.dev/badge/skills/hecer/yoke/authoring-prd.svg)](https://agentmods.dev/skills/hecer/yoke/authoring-prd)
Your own site
<a href="https://agentmods.dev/skills/hecer/yoke/authoring-prd"><img src="https://agentmods.dev/badge/skills/hecer/yoke/authoring-prd.svg" alt="Measured on agentmods" height="20"></a>
Per session 27 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 577 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 5.1 $0.00027 $0.00577
Opus 5 $0.00014 $0.00289
Sonnet 5 $0.00005 $0.00115
Haiku 4.5 $0.00003 $0.00058

Measured 5d ago against content hash 3366ff9edeab, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

authoring-prd 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 5d 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.

canon/skills/authoring-prd/SKILL.md · 59 lines

How it starts

The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Authoring a PRD

The Yoke loop is only as good as its stories. Keep the backlog continuous: new requests become new stories; they do not require a release object.

Story rules

  1. One iteration per story. Prefer 5–12 small stories over a few epics.
  2. Each story leaves the project buildable and testable.
  3. Acceptance describes observable behavior, never implementation. Give each of 2–5 criteria a stable id, behavioral text, and verify list with one or more real commands proving that exact outcome.
  4. Use dense priorities from 1; order by dependency, then risk.
  5. Greenfield STORY-1 creates the skeleton, runnable suite, and verify.command.
  6. Express performance with numbers and executable benchmarks, not words such as “fast”.
  7. Resolve planning questions before unattended execution. yoke prd check rejects unresolved placeholders; critical irreversible choices use the structured decision channel.
  8. Use needs only for hard prerequisites, area for collision domains, and agent only as a Claude/Codex/Gemini affinity hint.

Format (.yoke/prd.yaml)

- id: STORY-1
  title: scaffold a TypeScript CLI with vitest
  priority: 1
  acceptance:
    - id: cli-help-runs
      text: the CLI help command exits 0 and prints usage
      verify: [npm run test:cli-help-runs]
    - id: test-runner-starts
      text: the project test runner starts and reports at least one passing test
      verify: [npm run test:test-runner-starts]
  passes: false
- id: STORY-2
  title: add the sum command
  priority: 2
  needs: [STORY-1]
  area: cli
  agent: codex
  acceptance:
    - id: sum-valid
      text: cli sum 1 2 prints 3
      verify: [npm run test:sum-valid]
    - id: sum-invalid
      text: non-numeric input exits 1 with an error message
      verify: [npm run test:sum-invalid]
  passes: false

Every story has 2–5 structured criteria. Each verify entry is one approved test command whose normalized text contains its criterion ID; never use shell operators or a broad unrelated suite. passes is owned by the loop and always starts false. Validate with yoke prd check.

Read the full file on GitHub · 59 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. 5d ago First seen · 59 lines · 27 tokens per session scan A 3366ff9edeab

Subscribe to this mod's changes

authoring-prd is a skill published in the GitHub repository HECer/yoke (2 stars, last pushed 3d ago), licensed MIT. It adds 27 tokens to every session and 577 once invoked, about $0.0001 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 2026-08-31.