Immediate result: User stories in INVEST shape with Given/When/Then acceptance criteria and edge cases.
Problem it solvesUser stories lack acceptance criteria, so engineering and QA interpret them differently.
Users can reset their password by email
As a user who forgot my password, I want a reset link by email so that I can get back in.
Given a registered email, when I request a reset, then a link valid for 30 minutes is sent.
Edge: unregistered email shows the same message (no account enumeration).
User stories without acceptance criteria get interpreted differently by engineering and QA, and the difference shows up in production. This skill splits a feature into small, independent stories, writes each in the 'As a… I want… so that…' form, and adds Given/When/Then acceptance criteria covering edge and error cases. It flags stories too big for one sprint and lists what's out of scope. The stories are ready to paste into Jira or Linear, and testers can write test cases straight from the criteria. To use it, paste the skill into your assistant and send a feature or requirement description; the reply is laid out as “Story list”, “Acceptance criteria per story” and “Edge cases”.
# Skill: User story writer
You are running the "User story writer" skill for me. I work as: Product owner / PM. What I need from you: user stories in INVEST shape with Given/When/Then acceptance criteria and edge cases.
## When I send you a feature or requirement description
1. Split the feature into small, independent stories.
2. Write each as 'As a… I want… so that…'.
3. Add Given/When/Then acceptance criteria including edge and error cases.
4. Flag stories too big for one sprint.
## Reply in this format
- Story list
- Acceptance criteria per story
- Edge cases
- Out of scope
## Rules
- Use only the facts I give you; mark anything you had to assume with [ASSUMPTION].
- If something essential is missing, ask me one short question, then continue.
- No preamble or filler: start with the result.
Confirm you're ready in one line, then wait for me to send a feature or requirement description.Then sendA feature or requirement description. For example: Users can reset their password by email
Upload it to Claude, add it to ChatGPT's Codex app, clone it into Claude Code, or download the SKILL.md for any agent. Full guide with screenshots →
Download the ZIP and upload it in Claude. Claude then uses the skill on its own whenever a request matches.
Download ZIP
OpenAI's Codex app reads the same SKILL.md format. Copy the skill into your Codex skills folder:
$ git -c http.version=HTTP/1.1 clone https://scienceofapps.com/skills/ai-skills.git
$ cp -r ai-skills/user-story-writer ~/.codex/skills/
Clone the library and copy this skill into your Claude Code skills folder.
$ git -c http.version=HTTP/1.1 clone https://scienceofapps.com/skills/ai-skills.git
$ cp -r ai-skills/user-story-writer ~/.claude/skills/~/.claude/skills/ for all projects, or .claude/skills/ inside one project.Download the skill file and put it in a folder named after the skill.
Download SKILL.md~/.claude/skills/user-story-writer/SKILL.md.Repositoryscienceofapps.com/skills/ai-skills.git · all 200 skills, one folder each, plain git over HTTPS
User stories lack acceptance criteria, so engineering and QA interpret them differently. The skill fixes that: user stories in INVEST shape with Given/When/Then acceptance criteria and edge cases.
Copy the skill and paste it as the first message of a new chat, then send your input. To keep it, paste it into a ChatGPT Project or custom GPT, a Claude Project or a Gemini Gem, or upload the SKILL.md file as a Claude Skill.
Send a feature or requirement description. If something essential is missing, the skill asks you one short question and then continues.
Yes. It's free to copy, use and adapt, with no sign-up, and works in the free versions of ChatGPT, Claude, Gemini and Copilot.
ProblemThe backlog is prioritised by whoever shouts loudest.
1) Saved carts 2) Hindi UI 3) Dark mode — 40k MAU
Saved carts: 8,000 × 2 × 80% ÷ 3 = 4,267
Hindi UI: 12,000 × 2 × 50% ÷ 8 = 1,500 (confidence low — test demand first)
Dark mode: 10,000 × 0.5 × 80% ÷ 2 = 2,000
Immediate resultA ranked backlog with RICE scores, the maths shown and the assumptions to challenge.
ProblemCustomer interview notes pile up and the insights never reach the roadmap.
Notes from 8 interviews with small restaurant owners about online ordering
Theme: commission anger — 7/8 · 'Swiggy takes 25%, I make nothing on a biryani.'
Job: 'Get repeat customers to order direct without losing them.'
HMW: help owners move regulars to direct ordering without an app?
Immediate resultThemes, jobs to be done, pains and opportunities from your interviews, each backed by quotes.
ProblemExperiments launch without a hypothesis or success criteria, so results get argued about.
Test a one-page checkout vs three steps · baseline conversion 3% · 8,000 checkouts/week
Hypothesis: because 40% drop at the address step, one page will raise conversion for mobile users.
To detect +15% relative (3.0 → 3.45%) at 80% power: ~24,000 per arm ≈ 6 weeks.
Decision rule: ship if p < 0.05 and refund rate is unchanged.
Immediate resultAn experiment plan with hypothesis, variants, metric, sample size, duration and decision rule.
All 14 product management skillsAll 200 skillsRead it in the articleProve it: AI for Product Managers Certification (free test)
60 research-backed principles in 6 categories — what each one means, why it works on the human brain and how to use it on your own screens. Written by Sushant Singh, founder of Science of Apps, who has scaled consumer apps to lacs of users and spent 10+ years leading product across startups and digital businesses in the US, EU & India.
110 real paywalls from top apps, taken apart, rated out of 5 and decoded with the Laws of UX — plus the frameworks, copy and checklists to ship your own. By Sushant Singh, founder of Science of Apps.