design-rationale

design-rationale is a skill for Claude Code from Owl-Listener/designer-skills. It costs 39 tokens per session (384 once invoked), scanned A, original, MIT.

A writing guide for explaining why a decision was made, linking it to user needs, goals, evidence, alternatives, and trade-offs.

In plain words
What is it for?
Use it to document product or design decisions, especially when alternatives were considered or the choice may be questioned later.
Why use it?
It makes important choices easier to review and defend instead of presenting them as unexplained preferences.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the designer-toolkit plugin — 7 skills, 4 commands shipped together

Good fit Use it to document product or design decisions, especially when alternatives were considered or the choice may be questioned later.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/owl-listener/designer-skills/design-rationale
About the project

Owl-Listener/designer-skills is a collection of AI-agent skills, commands, and plugins for design work, covering research, design systems, interfaces, interaction, and delivery. Designers and developers use it inside coding assistants to guide design tasks, and the catalogue entries represent selected parts of that larger collection.

Owl-Listener/designer-skills · 2,609 stars · on GitHub

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.

Any agent
npx skills add Owl-Listener/designer-skills --skill design-rationale
Clone the repo
git clone --depth 1 https://github.com/Owl-Listener/designer-skills

Made for: Claude Code.

Or install designer-toolkit, the plugin that ships this one along with the rest of its 7 skills, 4 commands.

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 design-rationale

README.md
[![agentmods](https://agentmods.dev/badge/skills/owl-listener/designer-skills/design-rationale/github.svg)](https://agentmods.dev/skills/owl-listener/designer-skills/design-rationale)
Your own site
<a href="https://agentmods.dev/skills/owl-listener/designer-skills/design-rationale"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/design-rationale/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.

agentmods 80×15 button for design-rationale

Your own site · 80×15
<a href="https://agentmods.dev/skills/owl-listener/designer-skills/design-rationale"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/design-rationale.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 384 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 18 Mar 2026
  • Snyk pass 9 Mar 2026
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00039 $0.00384
Opus 5 $0.00019 $0.00192
Sonnet 5 $0.00008 $0.00077
Haiku 4.5 $0.00004 $0.00038

Measured 11d ago against content hash d451c85c3868, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

design-rationale 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

designer-toolkit/skills/design-rationale/SKILL.md · 42 lines

What it actually says

Design Rationale

You are an expert in articulating the reasoning behind design decisions.

What You Do

You write clear design rationale that connects decisions to evidence, principles, and goals.

Rationale Structure

1. Decision

What design decision was made? Be specific about what was chosen.

2. Context

What problem or need prompted this decision? What constraints exist?

3. Options Considered

What alternatives were explored? Brief description of each.

4. Evidence

What informed the decision? User research, data, best practices, competitive analysis, usability testing.

5. Reasoning

Why this option over the alternatives? Connect to user needs, business goals, design principles, and technical feasibility.

6. Trade-offs

What are the known compromises? What was deprioritized and why?

7. Validation Plan

How will you know if this decision was right? What metrics or feedback will confirm?

When to Write Rationale

  • Major design direction decisions
  • Departures from established patterns
  • Controversial or debated choices
  • Decisions that will be questioned later
  • Changes from previous approaches

Rationale Quality Checklist

  • Connects to user needs (not just designer preference)
  • References evidence or principles
  • Acknowledges alternatives and trade-offs
  • Is specific enough to be useful months later
  • Written for the audience who will read it

Best Practices

  • Write rationale during the decision, not after
  • Keep it concise but complete
  • Store rationale alongside the design files
  • Reference in handoff documentation
  • Use rationale in design reviews to explain choices
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. 11d ago First seen · 42 lines · 39 tokens per session scan A d451c85c3868

Subscribe to this mod's changes

design-rationale is a skill published in the GitHub repository Owl-Listener/designer-skills (2,609 stars, last pushed 5d ago), licensed MIT. It adds 39 tokens to every session and 384 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 2026-08-30.

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