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
ChordPolyPad
"ChordPolyPad" is a MIDI chords player that lets you create chord sets using a large internal library, any custom combination of notes, or randomly generated chords.
$17.99 · In-app purchases
PRICE
$17.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 4.6
50 ratings · Top 15%
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 ChordPolyPad: 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 free trial or freemium model to attract more users.
Assumption to check: High price point discourages new users
Validate with people who use this workflow before building.
Hypothesis 2
Integrate more sound libraries or allow user uploads.
Assumption to check: Limited sound options
Validate with people who use this workflow before building.
Hypothesis 3
Simplify onboarding and provide tutorials for new users.
Assumption to check: Complex UI for beginners
Validate with people who use this workflow before building.
Hypothesis 4
Add real-time collaboration tools for users to work together.
Assumption to check: No collaborative 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
"ChordPolyPad" is a MIDI chords player that lets you create chord sets using a large internal library, any custom combination of notes, or randomly generated chords. Each preset contains either 8 groups of 16 pads or 2 groups of 64 pads, for a total of 128 pads. In addition to playing chords, each pad can generate customizable MIDI controls on its horizontal and vertical axes, allowing expressive real-time modulation. "ChordPolyPad" can be used as a standalone application or as an AUv3 MIDI effect plug-in. The app supports full internal and external MIDI input and output. An internal sound bank is included for immediate use. The AUv3 MIDI effect plug-in supports multiple instances. A compatible host is required and must support the Audio Unit v3 (AUv3) MIDI effect format. Hosts supporting AUv3 MIDI effect on iOS: Logic Pro, Cubasis, Beatmaker, AUM, Audiobus, NanoStudio, Auria Pro, apeMatrix. Hosts supporting AUv3 MIDI effect on macOS: Logic Pro 10.7 or later. Features: • Standalone application and AUv3 MIDI effect plug-in • 8 groups of 16 pads or 2 groups of 64 pads per preset (128 pads) • Assignable MIDI port and MIDI channel for each pad • Customizable X/Y controller per pad • Per-note velocity control for each chord • Strumming configuration per pad • Copy and paste for pads and groups • Drag and drop chords directly from the library • Chord filtering and quantizing based on the selected scale • Predefined scales and possibility to create custom scales • Advanced random chord generator with diverse musical moods featuring voice leading and context-aware harmonic progressions for naturally flowing compositions • Stop "Audio Background" automatically after inactivity (15 min, 30 min, 1 h, 2 h, or never) • Internal sound bank • Receive MIDI notes and control from external devices • Send MIDI to a virtual port usable as MIDI input by other "Core MIDI" compatible apps • Preset manager with support for in-app purchase packs • "Program Change" support • Preset sharing support by "AirDrop", "Mail", "Messages", and other supported services • Native iCloud support • "iCloud Drive" support in the "Files" app on iOS and "Finder" on macOS • Full support for "Windowed Apps" mode on iPad • Undo/Redo Supported MIDI connections: • Virtual "Core MIDI" connections between apps • Any compatible MIDI interface • MIDI over Wi-Fi • MIDI over Bluetooth
Written user reviews are not shown here. Check current App Store reviews >
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.
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BUILD KIT DIFFICULTY
Advanced
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.
