A distilled, English-language playbook for designing SaaS & startup products that convert, retain, and monetize — packaged as an Agent Skill for Claude Code, Cursor, Codex, Copilot, Gemini, and any skills.sh-compatible agent.

101 principles distilled from the X/Twitter writing of Richard (@richardrx) — a product designer specializing in conversion-rate optimization, churn reduction, and applied behavioral science (ex-Volkswagen, ex-PayPal, ex-IBM). The throughline is his coined philosophy, Revenue-Centric Design (RCD): design should serve the user and the business — value and revenue, not one or the other.

Last updated: 1 July 2026 Coverage: @richardrx's curated posts from 14 Jan 2026 → 1 Jul 2026 (101 posts). Anything posted after this date is not yet included — see Updating.

npx skills add heliocosta-dev/revenue-centric-design

This pulls the skill into your agent's skills directory (.claude/skills/, .agents/skills/, …) and works with any Agent Skills–compatible agent.

Already installed it? Pull the latest version with npx skills update revenue-centric-design (or a bare npx skills update to refresh every installed skill). The command re-fetches from GitHub; your agent picks up the new content on its next session.

Or install it manually:

git clone https://github.com/heliocosta-dev/revenue-centric-design.git ~/.claude/skills/revenue-centric-design

🚫 Not for betting, casino, or gambling products. The author granted permission to reuse this material on the explicit condition that it is never used for gambling/betting/casino work (including loot-box / real-money-gaming mechanics). The skill instructs agents to decline such requests. See LICENSE.

The skill loads only the theme relevant to your question (progressive disclosure). Each principle follows a fixed shape — Principle → Apply when → The move → Evidence → Visual → Source — so your agent gets the named lever (decoy effect, Swiss Knife Index, GBB, Eugene Schwartz's awareness levels, loss aversion, peak-end rule…), the concrete action, and the proof.

The agent entry point is SKILL.md; informational diagrams referenced by the principles live in assets/.

1. Neutrality is omission — an interface that doesn't direct hurts conversion.
2. Who talks to everyone convinces no one — no ICP → generic value → worse retention.
3. Value first, ask later — proof must arrive before the user questions their choice.
4. Your promise is the size of your proof — the market believes what you demonstrate, not what you claim.
5. Same competes on price, different on category — no contrast, no margin.
6. Default is the decision you made for the user — the initial state defines mass behavior.
7. Retention is built, not requested — perceived loss retains more than promised benefit.
8. Expansion is born of usage — upgrade at the moment of the limit, never by interruption.
9. Price is a filter — pricing defines who enters, who stays, and who expands.

This is a point-in-time snapshot. The Coverage date above marks the latest included post (1 Jul 2026); anything newer from @richardrx isn't here yet. To extend it: gather the newer posts, distill each into the same principle shape, file it under the right references/ theme, then bump the dates in this README and in CHANGELOG.md.

All ideas, frameworks, examples, and the coined term Revenue-Centric Design belong to Richard (@richardrx). This repository is a curated, distilled, English-translated index of 101 of his public X posts, created with his permission for educational reference. Every principle links back to its original post, and it reproduces distilled principles rather than his full posts verbatim.

Source-available under custom terms — attribution required, no gambling/betting/casino use. See LICENSE. The underlying ideas remain the author's.