Feature spec
Goal: Send a clear invoice after finishing a job.
- Add a client, line items, a due date, and payment instructions.
- Preview the total before exporting a PDF.
- Keep an editable draft if export fails.
App Overview
Cheeky Fingers - Piano Chords
Cheeky Fingers is a beautifully crafted piano chord dictionary for iPhone & iPad
$3.99 · In-app purchases
PRICE
$3.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.4
72 ratings · Top 30%
Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.
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Build Kit
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A product spec, screen plans, and build steps for your coding agent.
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What's included16 files
A product spec, phased build plan, differentiation notes, and screen references.
- START_HERE
- AGENTS
- EVIDENCE
- SPEC
- BUILD_PLAN
- DIFFERENTIATION
- skills/
- screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.
Screen plan
Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.
States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.
Differentiate and validate
Hypothesis: Contractors need faster repeat invoices more than more templates.
First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.
The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.
Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.
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Free quick prompt For a smaller starting point
Quick prompt
Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.
// RORK SYSTEM PROMPT
Rork plan preview for Cheeky Fingers - Piano Chords: map the core Music workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
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Opportunities
AI-GENERATED OPPORTUNITY HYPOTHESES
These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.
Hypothesis 1
Offer a wider range of free chords or a trial period for premium chords.
Assumption to check: Limited chord selection in the free version
Validate with people who use this workflow before building.
Hypothesis 2
Implement visual feedback when chords are played to enhance learning.
Assumption to check: Poor user feedback for chord playing
Validate with people who use this workflow before building.
Hypothesis 3
Ensure high-quality audio samples for each chord.
Assumption to check: Inconsistent audio quality
Validate with people who use this workflow before building.
Hypothesis 4
Introduce social sharing or community-driven content to engage users.
Assumption to check: No community features
Validate with people who use this workflow before building.
App evidence
Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.
App Store description
Cheeky Fingers is a beautifully crafted piano chord dictionary for iPhone & iPad. We've designed a beautiful sidekick for any beginner or advanced pianist. No fuss, no confusing menus or terminology - just the chords, in a handy little app. Choose a key to see chord variations, related chords and great sounding progressions in that key. Find chord inspiration for your next song. Features: · Quick access to hundreds of chords · Find chords that sound great together · View accurate musical notation · Listen to great sounding progressions · Add and share your own progressions · Playback as chords or arpeggio · View chord inversions · Slow, medium and fast playback · 4 great sounding pianos · Toggle between octaves · No in-app purchases · Buy once and install on iPhone & iPad
Written user reviews are not shown here. Check current App Store reviews >
Screenshots
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Build scope
Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.
Define the first version
Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.
Set boundaries
Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.
Check the hard parts
Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.
SUGGESTED BUILD STACK
React Native
Expo
Supabase
Zustand
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expo-av
BUILD KIT DIFFICULTY
Starter
From the Build Kit assessment.
A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.
