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.
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 Owl-Listener/designer-skills --skill heuristic-evaluationgit clone --depth 1 https://github.com/Owl-Listener/designer-skillsWrote 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/owl-listener/designer-skills/heuristic-evaluation)<a href="https://agentmods.dev/skills/owl-listener/designer-skills/heuristic-evaluation"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/heuristic-evaluation/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/owl-listener/designer-skills/heuristic-evaluation"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/heuristic-evaluation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector pass
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 | $0.00050 | $0.00430 |
| Opus 5.5 | $0.00020 | $0.00172 |
| Sonnet 5.5 | $0.00010 | $0.00086 |
| Haiku 4.5 | $0.00005 | $0.00043 |
Grade A, and why
heuristic-evaluation 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 1mo 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.
What it actually says
Heuristic Evaluation
You are an expert in conducting systematic heuristic evaluations of digital interfaces.
What You Do
You evaluate interfaces against established usability heuristics to identify problems before user testing.
Nielsen's 10 Usability Heuristics
- Visibility of system status — Users know what is happening
- Match real world — System speaks users' language
- User control and freedom — Easy undo and exit
- Consistency and standards — Follow conventions
- Error prevention — Prevent problems before they occur
- Recognition over recall — Make options visible
- Flexibility and efficiency — Shortcuts for experts
- Aesthetic and minimalist design — No irrelevant information
- Error recovery — Help users recognize and recover from errors
- Help and documentation — Provide assistance when needed
Evaluation Process
- Define scope (which screens/flows to evaluate)
- Walk through as a new user
- Walk through as an experienced user
- Walk through each task flow
- Document each issue found
- Rate severity
- Compile and prioritize findings
Issue Documentation
For each issue: heuristic violated, description, location, severity (0-4), screenshot/reference, recommendation.
Severity Scale
- 0: Not a usability problem
- 1: Cosmetic only
- 2: Minor problem
- 3: Major problem (important to fix)
- 4: Catastrophe (must fix before release)
Best Practices
- Multiple evaluators find more issues (3-5 ideal)
- Evaluate independently before comparing
- Focus on real user tasks, not edge cases
- Don't just find problems — suggest solutions
- Combine with real user testing for complete picture
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.
- 1mo ago First seen · 42 lines · 50 tokens per session scan A 6bdacce0f15d
heuristic-evaluation is a skill published in the GitHub repository Owl-Listener/designer-skills (3,079 stars, last pushed 1mo ago), licensed MIT. It adds 50 tokens to every session and 430 once invoked, about $0.0002 per session on Opus 5.5. 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
ui-review
Review UI code for StyleSeed design-system compliance, accessibility, mobile ergonomics, spacing discipline, and implementation quality.
design-craft
Design or substantially improve user-facing interfaces with a product-specific visual direction, content hierarchy, and rendered critique. Use for new screens, landing pages, redesigns, typography/layout work, or UI that feels generic or AI-generated. For small fixes, preserve the existing design without starting a…
design-critique
Use this skill to audit an interface that already exists and say precisely why it looks generated, templated, or unfinished — a scored rubric across composition, typography, color, states, accessibility and copy, ending in a ranked fix list. Triggers: user says "review the design", "critique this UI", "why does this…
design-reference-read
Read a reference website or screenshot the way a designer does — by measuring it. Produces a dated "design DNA" record (color roles, type scale and ratio, spacing unit, radii, elevation, motion, section rhythm per viewport, component geometry, declared tokens) with measured and inferred values kept apart, names the…
anti-slop-frontend
A mechanical, countable anti-slop checklist for AI-generated frontend. Catches the specific signatures an undirected model defaults to: AI-purple glows, Inter-everywhere, em-dashes, div-based fake screenshots, eyebrow-on-every-section, beige+brass "premium" palettes, generic Jane Doe / Acme data. Advisory layer that…
design-to-code
Implement a supplied Figma design, screenshot, live reference site or design specification as a working interface, and prove the match with measured fidelity scores per axis (color, type, space, shape, layout, motion) instead of eyeballing. Use when matching a reference or handling design handoff; preserve its layout…