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
Cal AI - Calorie Tracker
HOW TO USE CAL AI:
Free · In-app purchases
PRICE
Free
In-app purchases
BUSINESS MODEL
Freemium
No overall Grossing estimate available
RATING
★ 4.8
365,290 ratings · Top 5%
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/
Preview a sample Build Kit No email needed
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 Cal AI - Calorie Tracker: map the core Health & Fitness 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
Implement a more comprehensive and quicker search algorithm.
Assumption to check: Users report difficulty in food database search functionality.
Validate with people who use this workflow before building.
Hypothesis 2
Simplify the meal logging UI with smart suggestions and faster data entry.
Assumption to check: Some users find the meal logging process cumbersome.
Validate with people who use this workflow before building.
Hypothesis 3
Add support for syncing with popular fitness trackers and wearable devices.
Assumption to check: Limited integration with fitness tracking devices.
Validate with people who use this workflow before building.
Hypothesis 4
Optimize the app's performance for lower-end devices.
Assumption to check: Inconsistent performance on older devices.
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
HOW TO USE CAL AI: 1) Answer lifestyle questions to build your plan 2) Snap a photo of your meal* 3) Get your nutritional breakdown* If you want to get your dream body, Cal AI will help you get there with less time spent than anyone else. We aren't another complicated diet app. We want to empower everyone to be confident in their bodies with minimal time spent, but you have to work hard. We will support you and give you the tools and information you need. If you have any ideas or questions, please email us at [email protected]. NOTE: We do not offer medical advice. Any and all recommendations should be viewed as suggestions, please consult with a professional and do your own research before trying a new calorie and nutrient plan. *FOOD SCANNING ANALYSIS RESULTS REQUIRE A SUBSCRIPTION TERMS: https://calai.app/tos
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
Zustand
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@react-native-community/async-storage
axios
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.
