usability-tester

Installation
SKILL.md

Usability Tester

Overview

Validates that users can successfully complete core tasks through systematic observation and expert evaluation. Covers moderated and unmoderated testing, heuristic evaluation, accessibility checks, and issue severity scoring. Not a substitute for analytics or A/B testing -- those measure what happens, usability testing reveals why.

When to use: Testing user flows, validating designs, identifying friction points, running heuristic evaluations, ensuring users can complete core tasks, planning and executing usability test sessions.

When NOT to use: Analytics or A/B test setup, visual design critique without task-based evaluation, automated UI testing (use a testing framework), performance benchmarking.

Quick Reference

Method Best For Participants When to Use
Moderated testing Deep insights, complex flows 5-8 per persona Design and prototyping stage
Unmoderated testing Scale, quantitative data 20-50+ Pre-launch and post-launch
Guerrilla testing Quick validation, early concepts 5-10 random Early concept stage
First-click testing Navigation, information architecture 20-50 Any stage, especially IA redesigns
Heuristic evaluation Expert review against principles 3-5 evaluators Before user testing, design audits
Related skills
Installs
37
GitHub Stars
11
First Seen
Feb 23, 2026