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
Cleartune
"My most indispensable app is my guitar tuner, Cleartune
$3.99 · In-app purchases
PRICE
$3.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
★ 3.7
884 ratings · Top 50%
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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A product spec, screen plans, and build steps for your coding agent.
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What's included15 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 Cleartune: 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
Expand instrument selection and tuning options.
Assumption to check: Limited instrument support compared to competitors
Validate with people who use this workflow before building.
Hypothesis 2
Implement better calibration options and user guides.
Assumption to check: Inconsistent calibration accuracy
Validate with people who use this workflow before building.
Hypothesis 3
Allow offline tuning features.
Assumption to check: No offline capabilities
Validate with people who use this workflow before building.
Hypothesis 4
Revamp UI for a modern look and feel.
Assumption to check: User interface feels outdated
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
"My most indispensable app is my guitar tuner, Cleartune. None of the old visual or analog tuners are as precise. I've even taken it on stage with me!" - Rosanne Cash "Cleartune and Clockwork are my most used apps." - Ezra Oklan (Nicole Atkins, Norah Jones, Antibalas Afrobeat Orchestra, Matt Beck (Matchbox 20), Chico Hamilton, Arnie Lawrence) "I've been having trouble with interference on stage with other tuners for the iPhone. Used Cleartune last night before a gig and had no problems with stage noise. Excellent tuner for bass." - Rob Calder (Kanye West, Angus and Julia Stone, The Break and Repair Method, Ghostface Killah) Used in the making of the Gorillaz album "The Fall" Follow us on Facebook at www.facebook.com/cleartune ----------------------------------- • Featured in Electronic Musician, Matchbox Mag, Making Music Mag, Premiere Guitar, MacWorld, Apple Staff Picks, Worship Leader Mag, Acoustic Guitar • Spotted in use backstage by The Black Keys, C.W. Stone King (www.va.ryanpolei.com), Grammy Nominee Sones de México (gearwire.com) ----------------------------------- Cleartune is a chromatic instrument tuner and pitch pipe that allows you to quickly and accurately tune your instrument using the built-in mic in your device. Cleartune features a unique "note wheel" interface allowing you to quickly find your pitch, paired with a highly responsive fine-tuning meter for the perfect tune. With support for custom temperaments, transposition, notations such as solfège, and adjustable calibration, Cleartune packs more power than most pro tuners, yet is simple enough for everyone to use. Cleartune can tune acoustic or electric guitar, bass, bowed strings, woodwinds, brass, piano, tympani and any other instrument that can sustain a tone. Most electronic tuners cannot properly tune a violin. With a built in temperament for violin family instruments, Cleartune will have the 5ths singing perfectly. Features: - Note Wheel Display - Ultra responsive 25 cent range fine tuning display - Needle Damping option - Accuracy ±0.01 semitone (±1 cent) - Selectable Temperaments - Selectable Notations (such as Solfège) - User-defined temperament and notations - Support for transposing instruments - Automatic reference note calibration - Adjustable A4 calibration in 0.1 Hz increment - Pitch Pipe/Tone generator - Selectable tone waveform - Automatic or manual note selection
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.
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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.
