Codex Startup User Simulator Skill

A Codex skill that tests a startup, SaaS, app, or landing page through five evidence-based simulated customer personas and explains why each would convert, hesitate, or leave.

It inspects the actual page, builds plausible decision-makers from the product's positioning, traces their conversion journeys, and returns prioritized fixes a founder can implement.

What It Does

• Tests live URLs, localhost apps, screenshots, prototypes, or pasted copy
• Simulates five distinct customer decision journeys
• Finds clarity, relevance, trust, friction, and CTA problems
• Separates observed evidence from inference and unknowns
• Produces a comparable persona scorecard
• Ranks five improvements by impact, effort, and confidence
• Creates a polished standalone HTML report with a clickable Codex file link
• Supports quick, deep, mobile, before/after, and copy modes
• Clearly labels simulation instead of presenting it as real user research

Installation

npx --yes codex-startup-user-simulator-skill@latest

This installs the skill into:

~/.codex/skills/startup-user-simulator

Restart Codex after installation so it can discover the skill.

Usage

Test a landing page:

Use $startup-user-simulator to test https://example.com with five simulated customer personas.

Deep desktop and mobile evaluation:

Use $startup-user-simulator in deep mode to test https://example.com. The target customer is an indie founder and the main conversion goal is starting a free trial.

Compare a redesign:

Use $startup-user-simulator in before-after mode to compare these two landing-page versions with the same five personas: [old URL] and [new URL].

Focus on copy:

Use $startup-user-simulator in copy mode to explain why customers may not understand this landing page and rewrite the highest-impact sections: [URL].

Output

The default report includes:

1. One-sentence verdict
2. Biggest conversion leak
3. Five-persona scorecard
4. Evidence-backed decision journeys
5. Five prioritized fixes
6. Fastest measurable experiment
7. Simulation limitations

Codex also creates a responsive HTML report in the workspace outputs/ directory and returns a clickable local link. The report includes expandable persona journeys, score visualizations, prioritized fixes, a printable layout, and a one-click “Save PDF” action.

Scores are structured heuristics, not predicted conversion rates or analytics.

Modes

• quick: primary-page verdict, scorecard, and top fixes
• deep: desktop, mobile, pricing, interactions, and CTA destinations
• mobile: small-screen conversion journey
• before-after: consistent comparison between two versions
• copy: positioning, objections, hero, and CTA language

Manual Installation

git clone https://github.com/Kappaemme-git/codex-startup-user-simulator-skill.git
mkdir -p ~/.codex/skills
cp -R codex-startup-user-simulator-skill/startup-user-simulator ~/.codex/skills/startup-user-simulator

Restart Codex after installation.

License

MIT