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-specs-designsgit 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-specs-designs)<a href="https://agentmods.dev/skills/liqiongyu/lenny_skills_plus/writing-specs-designs"><img src="https://agentmods.dev/badge/skills/liqiongyu/lenny_skills_plus/writing-specs-designs/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-specs-designs"><img src="https://agentmods.dev/badge/skills/liqiongyu/lenny_skills_plus/writing-specs-designs.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 | $0.00036 | $0.01971 |
| Opus 5 | $0.00018 | $0.00986 |
| Sonnet 5 | $0.00007 | $0.00394 |
| Haiku 4.5 | $0.00004 | $0.00197 |
Grade A, and why
writing-specs-designs 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 9d 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 — 137 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing Specs & Designs
Scope
Covers
- Producing a Spec & Design Doc Pack that helps product, design, and engineering quickly reach shared clarity
- Converting “insights” into concrete artifacts: a low‑fidelity diagram, flows/states, prototype plan, and testable acceptance criteria
- Mobile-specific tap economy (when relevant): explicitly optimizing taps and interaction cost
When to use
- “Write a spec / feature spec / technical spec for this feature.”
- “Turn these notes into a design doc that engineering can build from.”
- “Create a shaping-style doc with a diagram of the moving pieces.”
- “We need a prototype plan to evaluate the feel of this interaction.”
When NOT to use
- You’re still validating what problem to solve (do discovery / problem definition first).
- You need a high-level strategy/vision document (do product vision / north star work first).
- You need a deep engineering architecture design (APIs, schemas, scaling, reliability) rather than product interaction clarity.
- You only need pixel-perfect UI mocks (this produces specs and structured guidance, not final visuals).
- You need a decision-level PRD with requirements and success metrics but not build-ready flows -> use
writing-prds - You need expert design critique on an existing prototype -> use
running-design-reviews - You need to validate designs with real users -> use
usability-testing - You need to establish design-engineering handoff processes or design system standards -> use
design-engineering
Inputs
Minimum required
- Feature/change: 1–2 sentence description
- Target users + primary use case (happy path)
- Platform(s): web / iOS / Android / desktop (call out mobile explicitly)
- Goals + non-goals (v1 boundaries)
- Constraints: timeline, dependencies, policy/legal/privacy, technical constraints
- Success metrics (1–3) + guardrails (2–5)
Missing-info strategy
- Ask up to 5 questions from references/INTAKE.md, then proceed.
- If key info remains missing, state assumptions explicitly and provide 2–3 options (scope/flows/prototype approach).
What ships with it
13 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.
- eval/eval_config.json 611 B
- eval/SHOWCASE.md 5.5 KB
- eval/with_skill.md 30 KB
- eval/without_skill.md 16 KB
- README.md 1.6 KB
- references/CHECKLISTS.md 2.2 KB
- references/EXAMPLES.md 1.6 KB
- references/INTAKE.md 2.3 KB
- references/RUBRIC.md 3.0 KB
- references/SOURCE_SUMMARY.md 1005 B
- references/TEMPLATES.md 2.9 KB
- references/WORKFLOW.md 3.3 KB
- skillpack.json 387 B
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.
- 9d ago First seen · 137 lines · 36 tokens per session scan A 5b968abbad80
writing-specs-designs is a skill published in the GitHub repository liqiongyu/lenny_skills_plus (52 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 36 tokens to every session and 1,971 once invoked, about $0.0002 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.
Other skills, from other repositories
plan
Use when a request needs shaping before any code is written — a rough or vague prompt to sharpen, an ambiguous idea to design, or a clear-enough task to decompose. One chain-starter that amplifies the prompt, designs the approach, and decomposes it into a batched task file, skipping whichever phases the request…
decision-heuristics
A set of heuristics for making difficult personal decisions such as changing jobs, buying a home, moving, forming a partnership, or getting married. It is intended for major choices, not everyday decisions.
screen-detox
A habit-change framework for reducing non-work screen use such as social media, short videos, games, and endless scrolling.
monkey-mind-meditation
A meditation and reflection guide for a busy or anxious mind. It treats recurring thoughts as something to observe and examine, while noting that acute serious mental-health problems need professional care.
happiness-skill
A Chinese-language guide to happiness based on reducing unmet wants, focusing on the present, and treating happiness as a trainable skill.
peer-selection
A guide for thinking about which friends, partners, and social circles to keep close, based on shared values and their influence on your life.