Connect Claude or ChatGPT to GST Pro (MCP)

If you already work in Claude or ChatGPT, you can edit your GST Pro invoice templates from there. GST Pro provides a hosted MCP server (Model Context Protocol, the open standard AI assistants use to talk to apps). Connect it once with your Shopify login and your assistant can list your templates, read them, make edits in a private draft, render a preview and save, all from its own chat.

The connector uses your assistant's AI subscription. It does not consume GST Pro AI credits.

Availability

• Works with V2 templates. V1 templates cannot be read or edited through MCP.
• Requires a paid GST Pro plan and MCP switched on for your store.
• Works with Claude (custom connectors) and ChatGPT (custom apps in developer mode), and with any MCP client that supports remote servers with OAuth.

Step 1: Copy your server URL

1. In GST Pro, go to Settings → Integrations → MCP for Claude, or click the MCP button in the AI tab of the template editor.
2. In the Connect your AI assistant dialog, make sure MCP shows Enabled. Click Enable if it does not.
3. Click Copy URL next to MCP server URL.

Step 2: Add the connector in your assistant

Claude Open Claude's connector settings, add a custom connector, paste the server URL and choose OAuth.

ChatGPT In ChatGPT's developer mode, create a custom app with the server URL and OAuth authentication. Your ChatGPT workspace must allow custom apps.

Other MCP clients Add a remote MCP server with the URL and select OAuth. Most clients discover the login endpoints automatically.

Step 3: Approve the connection with Shopify

When the assistant connects for the first time:

1. A Connect GST Pro page opens. Enter your store domain (for example your-store.myshopify.com) and click Continue to Shopify.
2. Sign in to Shopify if prompted. GST Pro shows Allow Claude to access GST Pro? (or the name of your assistant) with the store it will access and what it can do:
   • Read template files and settings, validate queries and render previews using sample or store order data.
   • Edit and save V2 templates.
3. Click Allow connection, then Return to assistant.

Only approve apps you recognise. The connection appears under Connected apps in the GST Pro dialog, where you can Disconnect it at any time.

What your assistant can do

Once connected, ask your assistant in plain language, for example:

• "List my GST Pro templates and tell me which one is the default invoice."
• "Open my invoice template and add a bank details block under the totals."
• "Show me a preview of the packing slip on order #1042."
• "Change the accent colour to #0B5FFF and save."

Behind the scenes the assistant uses GST Pro's tools to inspect the template, search and read files, look up GST Pro's Liquid and schema reference, validate Liquid and the order query, capture a PNG preview, apply precise edits and save.

How edits stay safe

• The assistant works on a private draft copied from the saved template. Drafts expire after 24 hours.
• Unsaved changes sitting in your browser's template editor are not included in the draft.
• Nothing changes on your live template until the assistant calls save. Saving re-validates all template files and refuses to overwrite a template that changed in the meantime.
• If you only ask for a preview, or tell the assistant not to save, the draft is discarded.
• The order data query is read-only. The connector cannot change orders, customers or settings.

Managing connections

In Settings → Integrations → MCP for Claude:

• Connected apps lists each approved assistant with its callback origin and permissions. Click Disconnect to revoke it.
• Toggle Disable to switch MCP off for the whole store. Existing connections stop working immediately.
• If you used the earlier npm connector with an API key, it keeps working until you click Revoke previous key under Previous npm connection. After moving to the URL connector, revoke the key.

Access tokens last one hour and refresh automatically for 30 days, after which the assistant asks you to approve again.

Limits

• 120 tool calls per minute per store.
• 4 preview captures per draft.
• Previews may include customer information from the selected order. Use sample data when sharing screenshots.
• Preview rendering loads assets only from Shopify's CDN, Google Fonts and GST Pro's own storage.

Troubleshooting

Prefer to stay inside GST Pro? The AI tab in the template editor offers the same editing with a live preview and included monthly credits.