Use it in ChatGPT, Gemini and other AI chats

No connector option on your plan? There are two other ways to make a chat use the real rates: a Custom GPT, or a link the chat can read.

Which way is right for you?

Your situation	Use
Claude, ChatGPT (developer mode), Gemini CLI, Cursor, VS Code	The MCP server: one address and it just works.
ChatGPT with no connectors, and you want your own reusable assistant	A Custom GPT (about 5 minutes).
Any chat that can open web pages (ChatGPT, Gemini, Perplexity, Copilot, Claude…)	The link method (30 seconds, no setup).
Claude Projects, a system prompt or a company assistant	Paste instructions that point to the quote link.
Zapier, Make, n8n or a spreadsheet	Automation tools (HTTP request).

The link method (works almost anywhere)

Chats that can browse can read a calculation straight from an address. The format=md option returns a short readable answer with every tax, the rate version and the sources. Paste something like this and fill in your own values:

Say this to the chat

Open this address and explain the result in simple words, line by line:
https://autoimports.webgen.live/api/v1/quote?class=hybrid_petrol&cc=1500&age=1&cif=1600000&currency=JPY&format=md

Change class (for example petrol, diesel, hybrid_petrol, electric), cc (or kw, seats, payload, gvw), age, cif and currency. Not sure of the class? Ask the chat to open https://autoimports.webgen.live/api/v1/tax-classes first and pick one with you.

Build a Custom GPT (ChatGPT)

A Custom GPT is your own ChatGPT assistant that calls our API through "Actions". You need a ChatGPT plan that can create GPTs. People using your GPT can use it on any plan that allows GPTs.

In ChatGPT open Explore GPTs → Create, then switch to the Configure tab.
Name it, for example Sri Lanka Vehicle Import Tax, and write a one-line description.
Paste the instructions below into Instructions.
Under Actions choose Create new action, then Import from URL and enter https://autoimports.webgen.live/api/v1/openapi.json. The operations appear below the editor.
Set Authentication to None. Add the privacy policy address https://autoimports.webgen.live/privacy when asked for one.
Use the Preview pane to try the first test prompt below, then Create and choose who may use it.

Instructions to paste

You work out Sri Lankan vehicle import tax for people importing a car, van, bike or truck.

ALWAYS use the AutoImports actions for any figure. Never estimate tax from memory: rates change with each Sri Lanka Customs gazette.

Before calculating, make sure you know:
1. The vehicle type, and its fuel (petrol, diesel, hybrid, plug-in hybrid, electric). If unsure which tax class applies, call listTaxClasses and ask the user to choose.
2. Engine size in cc (or motor power in kW for electric, seats for buses, payload or gross weight for goods vehicles), as the class requires.
3. Vehicle age in years, when the class needs it.
4. The CIF value (cost + insurance + freight to Colombo) and its currency.
If any of these is missing, ask. Do not assume.

Then call calculateImportTax. In your answer:
- list each tax line, the total tax and the total landed cost in LKR;
- state the rateVersion and the ratesPublishedAt date;
- give the calculatorUrl so the user can save a PDF;
- say it is an estimate and that Sri Lanka Customs assesses the final duty.
Answer in the language the user writes in (English, Sinhala or Tamil).

Test prompt

I'm importing a 2021 Toyota Aqua hybrid (1,500 cc) from Japan. CIF is ¥1,600,000. What is the import tax?

ChatGPT asks the user to allow the action the first time. That is normal. Using a key is optional; if you have one, choose API key → Custom in the action authentication, with the header name X-API-Key (see getting a key). Keep a key out of any GPT you publish: people can use the action it holds.

Claude Projects, Gemini Gems and system prompts

Assistants that can fetch a web address but have no connector can follow plain instructions. Paste this into a Claude Project's instructions, a Gemini Gem, or your own system prompt:

Instructions to paste

When the user asks about Sri Lankan vehicle import tax, do not estimate. Use the AutoImports calculator:
- Quote: https://autoimports.webgen.live/api/v1/quote?class=<tax class>&cc=<engine cc>&age=<years>&cif=<amount>&currency=<JPY|USD|GBP|LKR>&format=md
- Tax classes (to find the right class key): https://autoimports.webgen.live/api/v1/tax-classes
Fetch the quote address with the user's values, then report each tax, the total landed cost, the rate version and the calculator link. Ask for any missing value first. It is an estimate; Sri Lanka Customs assesses the final duty.

Where the assistant has a real connector option, the MCP server is more reliable: the assistant gets a proper tool with defined inputs instead of building addresses by hand.

Zapier, Make, n8n and spreadsheets

Any tool that can send an HTTP request can call the API. Use the GET quote address for the simplest set-up, or POST JSON to /api/v1/calculate.

Tool	How
Zapier	“Webhooks by Zapier” → Custom Request, GET, the quote address with your fields mapped in.
Make	HTTP → Make a request. Method GET, the quote address; parse the JSON response.
n8n	HTTP Request node, GET or POST, response format JSON.
Google Sheets	An Apps Script custom function: `UrlFetchApp.fetch` the quote address, `JSON.parse` the response and return `totalTax` or `totalCost`.

Full field descriptions, error codes and code samples are in the REST API reference.

Getting reliable answers

Give the assistant the engine size, fuel, age and CIF value up front; they all change the tax.
CIF is the cost of the vehicle plus insurance and freight to Colombo, not the price in the seller's advert. See what CIF means.
Ask the assistant to show the rate version and the calculator link, so you can check the figures on the website.
Treat the result as an estimate: Sri Lanka Customs assesses the final duty.