replica-diff
Compares an app clone against the original: a feature parity score from the feature matrix (weighted by must, should, could) with the missing list in build order, plus a screenshot layout diff that ignores colour so a rebrand does not count against you. Two standard-library Python tools. Use when the user says "how close is my clone", "compare it to the original", "what's missing", "parity check", "diff the screens", "is it ready", or after /replica-test.
- Installs
- 669
- Last 24h
- +41
- Trending rank
- #3800
- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/jakeschincariol/replica-skill --skill replica-diff- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads replica-diff automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
replica-diff
Two tools in this folder, both standard-library Python, no installs:
python3 parity.py replica/features.csv # feature parity + missing list
python3 imgdiff.py replica/screens/S07.png replica/clone-screens/S07.png --out diff-S07.png
python3 imgdiff.py a.png b.png --json > replica/diffs/S07.json # for parity.py --visual
python3 parity.py replica/features.csv --visual replica/diffs/*.json --markdown > replica/parity.md
What parity means here
Parity means it does the same job, not that it looks the same. The feature score is the number that matters: can a user do everything they could do in the original. The layout score checks structure (is the information in the same places, in the same hierarchy), because that is what makes a switcher feel at home. It deliberately ignores colour, because replica-brand changes every colour on purpose. Do not chase pixel parity with the original. Its exact look is its trade dress, and it changes before launch.
Step 1: feature parity
Make sure replica/features.csv is current: every row's clone column is
yes, partial (with a note), no, or skip (with a reason). Then:
python3 parity.py replica/features.csv
It weights must 3, should 2, could 1, counts partial as half, leaves out
skip rows and rows you added that the original does not have, and prints:
the score, must-haves done of total, each area weakest first, and the missing
list in build order. Must-haves not done means not shippable, and it says so.
Step 2: layout diff
For each key screen, take two screenshots at the same viewport (1440x900
desktop, 390x844 mobile) in the same state (same data shape, same tab
open, logged in the same way). The original's come from public pages or the
user's own account, saved in replica/screens/. The clone's go in
replica/clone-screens/.
python3 imgdiff.py replica/screens/S07.png replica/clone-screens/S07.png --out replica/diffs/S07.png
Layout mode (default) turns both into edge maps, cuts them into a grid, and compares where things are, scoring only cells with something in them. It reports the score (matches 90+, close 75+, partly 50+, different), the regions that differ (in the original's pixel coordinates, biggest first), and a height difference if the clone's page is much longer or shorter. Retina and non-retina screenshots compare fine: both are scaled to the same width.
--mode pixel is exact comparison. Use it for your own regressions (clone
today against clone last week), not against the original.
Step 3: behaviour diff
Walk each flow in both apps and compare what the scores cannot see: clicks to finish the core flow, what happens on errors, what is remembered between visits, what emails arrive. Fewer clicks than the original is a win. Write each difference as: flow, original does, clone does, fix or keep.
Step 4: the report
replica/parity.md: overall score, feature score, layout score per screen,
missing features in build order, behaviour differences, and a verdict:
- not shippable: any must-have missing, or any open S1 bug
- shippable: all must-haves done, feature score 80+, no open S1 or S2
- better than the original: shippable, plus fixes from replica-entrepreneur. This is the goal. A straight copy has no reason to exist.
Give honest numbers. A clone at 62% is at 62%.
Output
replica/parity.md, the diff images, and the top five things to build next.
Then /replica-build for the gaps, or /replica-entrepreneur if parity is
there.
FAQ
What does the replica-diff skill do?
Compares an app clone against the original: a feature parity score from the feature matrix (weighted by must, should, could) with the missing list in build order, plus a screenshot layout diff that ignores colour so a rebrand does not count against you. Two standard-library Python tools. Use when the user says "how close is my clone", "compare it to the original", "what's missing", "parity check", "diff the screens", "is it ready", or after /replica-test.
How do I install replica-diff?
Run npx skills add https://github.com/jakeschincariol/replica-skill --skill replica-diff in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/replica-diff/ (personal) or .claude/skills/replica-diff/ (project).
Which AI agents can use replica-diff?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is replica-diff safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains replica-diff?
It is published by jakeschincariol in jakeschincariol/replica-skill. It has 669 recorded installs.
More from jakeschincariol/replica-skill
replica-recon
jakeschincariol/replica-skill
Reverse-engineers any app into a recon map: screen inventory, user flows, component list, inferred data model and a feature matrix, from public pages, screenshots, app store listings, help docs and the user's own account. The first step of the Replica pack. Use when the user says "clone this app", "reverse engineer X", "how does X work", "map out X", "what screens does X have", "I want to build my own version of X", "copy this app", or pastes an app's URL or App Store link and wants to rebuild it.
replica-entrepreneur
jakeschincariol/replica-skill
Researches the app being cloned and reads what its real users say in public reviews (App Store, Google Play, G2, Capterra, Trustpilot, Reddit, Hacker News, its own feature-request board), then ranks what they hate, what is missing and what is unsolved, turns it into a fix plan for the clone and a positioning angle you can sell. Every quote is real, verbatim and linked. Use when the user says "what do people hate about X", "read the reviews", "how do I make mine better", "find the gap", "what features are missing", "how do I position this", "make it sellable", or after /replica-diff.
replica-test
jakeschincariol/replica-skill
Clicks through every flow of an app clone and tests it for bugs: a test plan generated from the recon flows with happy paths and edge cases, Playwright end-to-end tests where possible, a browser click-through where not, and bug reports in a fixed format with severity, steps and evidence. Use when the user says "test my clone", "find bugs", "QA this", "click through everything", "write e2e tests", "does it work", or after /replica-build or /replica-backend.
replica-design
jakeschincariol/replica-skill
Rebuilds an app's design system for a clone: colour roles, type scale, spacing, radius, shadows and every component with its states, as design tokens plus component specs, with original assets instead of the target's logos, icons, illustrations or licensed fonts. Includes a WCAG contrast checker. Use when the user says "match the design", "rebuild the design system", "get the colours and fonts", "make it look like X", "design tokens for my clone", or after /replica-architect.
replica-build
jakeschincariol/replica-skill
Rebuilds an app screen by screen from the recon map: app shell first, then the core flow as a vertical slice, then every screen with all its states, ticking off the feature matrix as it goes. Writes every line fresh, never the original's code, assets or copy. Use when the user says "build the clone", "build screen S07", "start building", "rebuild this screen", "implement the booking page", or after /replica-design.
replica-launch
jakeschincariol/replica-skill
Writes the launch for an app clone: the landing page built on the positioning angle, pricing set against the original's public pricing and its users' complaints, and the App Store and Google Play listing linted against the stores' limits and copycat rules. Use when the user says "landing page", "pricing", "how much should I charge", "App Store listing", "store screenshots", "launch plan", "Product Hunt", or after /replica-brand.
Popular frontend & design skills
setup-matt-pocock-skills
mattpocock/skills
Configure this repo for the engineering skills: set up its issue tracker, triage label vocabulary, and domain doc layout. Run once before first use of the other engineering skills.
frontend-design
anthropics/skills
Guidance for distinctive, intentional visual design when building new UI or reshaping an existing one. Helps with aesthetic direction, typography, and making choices that don't read as templated defaults.
hyperframes-animation
heygen-com/hyperframes
All animation knowledge for HyperFrames — atomic motion rules, multi-phase scene blueprints, scene transitions, broader motion-design techniques, AND the seven runtime adapters (GSAP default, plus Lottie, Three.js, Anime.js, CSS keyframes, Web Animations API, TypeGPU). Use for any motion or animation task: pick 2-4 rules and compose, or load a blueprint, or look up runtime-specific API (e.g. GSAP eases / Lottie player / Three.js mixer). Also covers auditing an existing composition's choreography (animation map) and 24 named text-animation effects. HyperFrames-native: single paused timeline, seek-safe, deterministic.
prototype
mattpocock/skills
Build a throwaway prototype to answer a design question. Use when the user wants to sanity-check whether a state model or logic feels right, or explore what a UI should look like.
hyperframes-core
heygen-com/hyperframes
The HyperFrames composition contract — build one renderable project. Use for composition structure, the data- timing attributes, class="clip", tracks, sub-compositions, variables, framework-owned media playback, deterministic-render rules, and validation. Read before writing composition HTML.
vercel-react-best-practices
vercel-labs/agent-skills
React and Next.js performance optimization guidelines from Vercel Engineering. This skill should be used when writing, reviewing, or refactoring React/Next.js code to ensure optimal performance patterns. Triggers on tasks involving React components, Next.js pages, data fetching, bundle optimization, or performance improvements.