Quickstart

This quickstart builds a small billing connector: one tool that returns an invoice, a Presenter that keeps customer PII out of the model context, a live connection from an MCP client and a free deploy to Vinkius Cloud. It assumes you installed @mcpfusion/core and scaffolded a project as shown in Installation.

1. Create the server

import { initMCPFusion } from '@mcpfusion/core';

const f = initMCPFusion();

export default f;

initMCPFusion() returns a registry with the fluent tool builders. The generic parameter AppContext is optional: when you provide a type, every handler and middleware receives a typed ctx.

2. Define a Presenter

import { createPresenter, t } from '@mcpfusion/core';

const InvoicePresenter = createPresenter('Invoice')
  .schema({
    id: t.string,
    customer: t.string,
    amount_cents: t.number.describe('CENTS, divide by 100'),
    status: t.enum('draft', 'paid', 'overdue'),
  })
  .redactPII(['customer.email', 'customer.ssn'])
  .rules([
    'amount_cents is in CENTS. Divide by 100 before showing money.',
  ])
  .limit(50);

Three things happen here. The schema says exactly which fields exist, so undeclared columns never reach the agent. .redactPII() removes the listed paths on every response. .rules() become system prompt lines that teach the model the units.

3. Write the tool

import { InvoicePresenter } from './presenters';

export default f.query('billing.get_invoice')
  .describe('Retrieve an invoice by ID')
  .withString('id', 'Invoice ID')
  .returns(InvoicePresenter)
  .handle(async (input) => {
    return db.invoices.findUnique({
      where: { id: input.id },
    });
  });

f.query() marks the tool as read only. Use f.mutation() for writes and f.action() for anything with side effects. .returns(InvoicePresenter) attaches the perception layer: the handler may return the raw row, the Presenter does the shaping.

4. Connect a client

Start the dev server and connect Claude Desktop, Cursor or any MCP client:

mcpfusion dev --server ./src/server.ts
claude mcp add billing npx tsx src/server.ts

Ask the client "what is invoice inv_2026_0417?" and watch the answer come back in dollars, without the customer email anywhere in the transcript.

5. Deploy for free

mcpfusion deploy

One command bundles your server and puts it on the Vinkius Edge: free hosting, no credit card. You receive a connection token and an MCP URL such as https://edge.vinkius.com/vk_<token>/mcp. Your connector appears in the Vinkius console like any other connector, with capabilities, credentials and cost controls already wired. See Deploy for the full walkthrough.

What you built

Next steps

• The MVA pattern: why Presenters exist
• Tools: mutations, actions, middleware and errors
• Credentials: let buyers configure their own keys