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 liqiongyu/lenny_skills_plus --skill writing-prds-executablegit clone --depth 1 https://github.com/liqiongyu/lenny_skills_plusWrote 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/liqiongyu/lenny_skills_plus/writing-prds-executable)<a href="https://agentmods.dev/skills/liqiongyu/lenny_skills_plus/writing-prds-executable"><img src="https://agentmods.dev/badge/skills/liqiongyu/lenny_skills_plus/writing-prds-executable/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/liqiongyu/lenny_skills_plus/writing-prds-executable"><img src="https://agentmods.dev/badge/skills/liqiongyu/lenny_skills_plus/writing-prds-executable.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 | $0.00105 | $0.01222 |
| Opus 5 | $0.00053 | $0.00611 |
| Sonnet 5 | $0.00021 | $0.00244 |
| Haiku 4.5 | $0.00011 | $0.00122 |
Grade A, and why
writing-prds-executable 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 11d 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 — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing PRDs (Executable)
This skill turns messy ideas into shippable artifacts:
- PR/FAQ (customer-first narrative)
- PRD (scope + requirements + success metrics)
- AI Eval Spec (requirements as executable evals) — AI only
- Prompt Set / Prototype plan — AI only
Keep outputs crisp, concrete, and copy‑pasteable. Prefer bullets, tables, and numbered requirements over long prose.
When to use
Use this skill when the user requests:
- a PRD / product requirements / product spec / requirements doc
- a PR/FAQ or “working backwards” narrative
- acceptance criteria, rollout plan, risks, dependencies
- AI/LLM behavior requirements, evals, judge rubric, prompt sets
When NOT to use (redirect)
Do NOT use this skill as a substitute for:
- Company strategy / vision (use a vision/strategy skill)
- Roadmap prioritization across many initiatives (use prioritization/roadmap skill)
- Pure UX copywriting or marketing launch copy (use messaging/launch skills)
If legal/privacy/security constraints are material but unknown, first ask for constraints and the approval process.
Quick decision: which artifact(s) to produce
If the user doesn’t specify, choose the minimal artifact that unlocks the next decision:
- Early / unclear idea → PR/FAQ first, then a lightweight PRD outline.
- Clear direction, need alignment / build plan → PRD.
- AI/LLM feature → PRD + Eval Spec + Prompt Set (required).
- “Improve this existing PRD/spec” → rewrite + gaps + open questions.
Templates:
- PRD:
assets/PRD_TEMPLATE.md - PR/FAQ:
assets/PRFAQ_TEMPLATE.md - Eval Spec:
assets/EVAL_SPEC_TEMPLATE.md - Prompt Set:
assets/PROMPT_SET_TEMPLATE.md
Quality checks:
- Checklist:
references/QUALITY_CHECKLIST.md - Rubric:
references/QUALITY_RUBRIC.md - Question bank:
references/QUESTION_BANK.md
Intake: ask only what you must
Ask at most 5 high-leverage questions at a time (use references/QUESTION_BANK.md).
If the user can’t answer, proceed with explicit assumptions.
What ships with it
11 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.
- assets/EVAL_SPEC_TEMPLATE.md 1.5 KB
- assets/PRD_TEMPLATE.md 1.7 KB
- assets/PRFAQ_TEMPLATE.md 1.4 KB
- assets/PROMPT_SET_TEMPLATE.md 842 B
- README.md 539 B
- references/EXAMPLES.md 1.6 KB
- references/LENNY_SOURCE_NOTES.md 522 B
- references/QUALITY_CHECKLIST.md 1.6 KB
- references/QUALITY_RUBRIC.md 1.4 KB
- references/QUESTION_BANK.md 1.1 KB
- scripts/lint_prd.py 1.5 KB runs code
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.
- 11d ago First seen · 132 lines · 105 tokens per session scan A 10272e024635
writing-prds-executable is a skill published in the GitHub repository liqiongyu/lenny_skills_plus (52 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 105 tokens to every session and 1,222 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 2026-08-30.
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