Problem:

Since the introduction of GST 2.0, there has been a concern as to what rate of tax would apply to good/ services being supplied, i.e. whether the old rate of tax would be applicable or new rates would apply.

The said problem needs to be evaluated based on Section 14 of the CGST Act, 2017 i.e. the Time of Supply.

Solution:

The problem needs can be solved with a one go to solution wherein any user can select the required details from drop down and the result will be displayed accordingly.

The said solution will also help with selection of HSN (for services only, as of now) to check what rates were applicable in GST and what are applicable in GST 2.0.

Steps for building the solution:

1. Prompt using Prompt Engineer (Open AI) –

Give me a prompt where I want to generate an app through Claude AI for evaluating time of supply under GST due to change in GST rates w.e.f. 22 September 2025. Since time of supply is crucial for change evaluating what tax rate would apply, user will select drop down on required details as per Section 14 of CGST Act, i.e. time of supply.

1. Result -

You are an expert app builder specializing in tax compliance tools. Build a web-based app that helps businesses determine the correct GST rate when there is a change in GST rates effective from 22 September 2025, by applying the rules of time of supply under Section 14 of the CGST Act. App Requirements: 1. User Interface: * A clean, simple form-based UI. * Dropdown menus for the user to select key details, such as: * Date of supply of goods/services. * Date of issuance of invoice. * Date of receipt of payment. * Option to select whether the supply is goods or services. 2. Logic: * Implement Section 14 rules to determine which date will be considered the time of supply in cases where GST rates change. * Based on the chosen dates and details, the app should calculate whether the old rate (before 22 September 2025) or the new rate (on/after 22 September 2025) applies. 3. Output: * A clear display of: * The determined “time of supply.” * The applicable GST rate (old or new). * A short explanation of why that rate applies, referencing Section 14 provisions. 4. Technology Preferences: * Use lightweight web technologies (HTML, CSS, JavaScript, Python/Flask or Node.js backend). * Code should be modular and easy to extend for future rate changes. Deliverables: * Complete code for the app. * Instructions to run it locally. * Example test cases with sample dates to show correct application of GST rules.

1. Claude built a default app
2. Pushed data in backend through GST rate notifications on Claude
3. Several changes made with multiple follow ups for the app
4. App has been finally built with a single drop-down selection criteria for HSN related to services
5. Rates are auto populated based on details provided
6. As of now, the app is for the purpose of analysis of Time of Supply due to GST 2.0 for services and evaluate which rate of tax would apply

Upcoming features for the app – Selection criteria for HSN for goods, selection criteria for multiple HSN (Goods and Services both).