Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/sun2443/designer-skillsnpx agentmods add skills/sun2443/designer-skills/write-specWrote 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/sun2443/designer-skills/write-spec)<a href="https://agentmods.dev/skills/sun2443/designer-skills/write-spec"><img src="https://agentmods.dev/badge/skills/sun2443/designer-skills/write-spec/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/sun2443/designer-skills/write-spec"><img src="https://agentmods.dev/badge/skills/sun2443/designer-skills/write-spec.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 | $0.00060 | $0.02732 |
| Opus 5.5 | $0.00024 | $0.01093 |
| Sonnet 5.5 | $0.00012 | $0.00546 |
| Haiku 4.5 | $0.00006 | $0.00273 |
Grade A, and why
write-spec 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 13d 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.
This is a copy
100% identical to write-spec — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 251 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Write Spec
If you see unfamiliar placeholders or need to check which tools are connected, see CONNECTORS.md.
Write a feature specification or product requirements document (PRD).
Usage
/write-spec $ARGUMENTS
Workflow
1. Understand the Feature
Ask the user what they want to spec. Accept any of:
- A feature name ("SSO support")
- A problem statement ("Enterprise customers keep asking for centralized auth")
- A user request ("Users want to export their data as CSV")
- A vague idea ("We should do something about onboarding drop-off")
2. Gather Context
Ask the user for the following. Be conversational — do not dump all questions at once. Ask the most important ones first and fill in gaps as you go:
- User problem: What problem does this solve? Who experiences it?
- Target users: Which user segment(s) does this serve?
- Success metrics: How will we know this worked?
- Constraints: Technical constraints, timeline, regulatory requirements, dependencies
- Prior art: Has this been attempted before? Are there existing solutions?
3. Pull Context from Connected Tools
If ~~project tracker is connected:
- Search for related tickets, epics, or features
- Pull in any existing requirements or acceptance criteria
- Identify dependencies on other work items
If ~~knowledge base is connected:
- Search for related research documents, prior specs, or design docs
- Pull in relevant user research findings
- Find related meeting notes or decision records
If ~~design is connected:
- Pull related mockups, wireframes, or design explorations
- Search for design system components relevant to the feature
If these tools are not connected, work entirely from what the user provides. Do not ask the user to connect tools — just proceed with available information.
4. Generate the PRD
Produce a structured PRD with these sections. See PRD Structure below for detailed guidance on what each section should contain.
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.
- 13d ago First seen · 251 lines · 60 tokens per session scan A ca6670913878
write-spec is a skill published in the GitHub repository sun2443/designer-skills (0 stars, last pushed 6mo ago), licensed Apache-2.0. It adds 60 tokens to every session and 2,732 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to write-spec, differing in 0 lines, and is treated as a copy.
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