# Lean UX > Collaborative, experiment-driven UX design — an AI agent skill based on *Lean UX* by Jeff Gothelf & Josh Seiden. Published 2026-02-23 · Updated 2026-08-17 · Design & UX · Free and MIT-licensed Canonical: https://skills.wondel.ai/skills/lean-ux/ Source: https://github.com/wondelai/skills/tree/main/lean-ux **Install:** `npx skills add wondelai/skills/lean-ux --global` ## What is the Lean UX skill? Lean UX moves design from deliverables to experiments, applying Jeff Gothelf and Josh Seiden’s book of the same name. The skill has your agent restate a feature request as a testable hypothesis — we believe this change produces that outcome, and we will know when this metric moves — then design the smallest thing that could disprove it. ## Key concepts from Lean UX your agent applies - **Hypothesis-Driven Design** — Frame design decisions as hypotheses: "We believe [this change] will result in [this outcome]. We'll know we're right when [this metric changes]." - **Outcomes over Outputs** — Focus on changing customer behavior (outcomes), not shipping features (outputs). Measure success by impact, not delivery. - **Cross-Functional Collaboration** — Break down silos between design, engineering, and product. Co-create solutions with shared understanding. - **Design Studio Method** — Run collaborative sketching sessions where the whole team generates and critiques ideas together. - **Minimum Viable Product** — Design the smallest experiment that tests your riskiest assumption — a landing page, Wizard of Oz test, or concierge MVP. ## When to use Lean UX — and when not to Reach for it when: - Your roadmap is a list of features with no statement of what any should change. - Design hands over comps, engineering builds them, and nobody checks whether the outcome arrived. - Stakeholders argue about the solution because the assumption underneath it was never written down. - You want to test a redesign before committing a quarter to building it. Reach for something else when: - You need interview technique that stops users being polite — The Mom Test is the sharper tool. - You want a weekly discovery rhythm and opportunity solution trees — Continuous Discovery goes deeper. - The business model is unproven, not just this screen — Lean Startup operates at that altitude. - You want a tested prototype by Friday — Design Sprint is the packaged five-day version. ## About Jeff Gothelf & Josh Seiden Lean UX pioneers, bestselling authors and product coaches. Jeff Gothelf is an organizational designer and author who helps teams build better products through Lean and Agile principles. Josh Seiden is a designer and product leader who co-created the Lean UX methodology and pioneered outcome-based design practices. The book: https://openlibrary.org/books/OL27219926M/Lean_UX ## Example prompts - Frame this feature idea as a Lean UX hypothesis with measurable outcomes using lean-ux skill _(Product design)_ - Plan a design studio session for our cross-functional team using lean-ux skill _(Collaboration)_ - Design a minimum viable experiment to test our onboarding redesign using lean-ux skill _(Experimentation)_ - Shift our team from output-based to outcome-based success metrics using lean-ux skill _(Team process)_ ## Frequently asked questions ### How do I install the Lean UX skill? Run `npx skills add wondelai/skills/lean-ux --global`. It takes about 30 seconds and needs no account. The Lean UX skill then works in Claude, Claude Code, Claude Cowork, Codex, Cursor, OpenClaw and Hermes Agent — anything that reads the open agentskills.io format — and your agent loads it on its own when a task calls for it. It is free and MIT-licensed, and the source is at https://github.com/wondelai/skills. ### Which book is the Lean UX skill based on? It packages *Lean UX* by Jeff Gothelf & Josh Seiden — lean UX pioneers, bestselling authors and product coaches. The skill distils the book's method into instructions your agent follows while it works, covering hypothesis-driven design, outcomes over outputs and cross-functional collaboration. It sits in the Design & UX part of the library. ### How is it different from the Lean Startup skill? Same loop, different altitude. Ries is testing whether the business should exist — the unit of learning is a pivot or a persevere, and the experiment might be a fake landing page for a product with no code behind it. Lean UX runs inside a team that already has a product, testing design decisions: this flow, this onboarding step, this navigation model. If you are questioning the company, use Lean Startup. If you are questioning the screen, use this. ### Half the book is about cross-functional teams. Does it help a solo builder? The collaboration chapters are largely moot when you are one person and an agent — there are no silos to break and design studio with a single participant is just sketching. What survives is most of the value: writing the assumption down before you build, framing it as a hypothesis with a named metric, and picking the smallest test that could kill it. Solo founders skip this discipline most, so it pays off disproportionately. ### Do I need experiment infrastructure to run this? No, and assuming you do is what stops teams starting. Most of the MVPs here are qualitative and cheap: a landing page that measures intent, a Wizard of Oz test where a human does the work the feature will eventually do, a concierge version for five customers. Statistical testing only earns its place once you have the traffic for it. Until then, five users watching a prototype answers the question faster. ### Isn’t “outcomes over outputs” just a slogan? It becomes one the moment you cannot name the metric. The skill is deliberately strict here — if the hypothesis ends in “users will be more engaged” with nothing instrumented behind it, you have written a wish, not an experiment. Being forced to specify what would change, by how much, and where you would see it is most of the value; a fair number of feature ideas do not survive that sentence. ## Related - All Design & UX skills: https://skills.wondel.ai/skills/design/ - Refactoring UI: https://skills.wondel.ai/skills/refactoring-ui/ - iOS HIG Design: https://skills.wondel.ai/skills/ios-hig-design/ - UX Heuristics: https://skills.wondel.ai/skills/ux-heuristics/ - Web Typography: https://skills.wondel.ai/skills/web-typography/ - Design of Everyday Things: https://skills.wondel.ai/skills/design-everyday-things/ - Top Design: https://skills.wondel.ai/skills/top-design/ - Microinteractions: https://skills.wondel.ai/skills/microinteractions/ - Steve Jobs Design Review: https://skills.wondel.ai/skills/steve-jobs-design-review/