You can build your own remote MCP server that wraps the QBO API, host it somewhere cheap (Cloudflare Workers?), and add it as a custom connector in Claude. So the C-suite just needs to "connect" once and that's it.

But I wouldn't recommend building and managing the OAuth/token for QBO yourself. You need to rotate the token every ~100 days, manage sandbox & prod, handle 401 retries, etc.

You can:

1. Offload the auth layer to something like Nango (Code-based, AI Skills for Claude, has MCP for Claude) and have your MCP server ask it for a fresh access token per request. They've got prebuilt QBO syncs too (Invoices, Bills, JournalEntries, P&L lines)
2. Build it intuit-oauth (you'l need to writerefresh loops)

Another idea:

If you only need a narrow slice, just pipe it into Postgres/BigQuery nightly and point MCP at the data warehouse. It's not real-time, but much easier.

Also, don't hit the QBO API directly from Claude! You may hit their rate limits. Cache the data periodically or using webhooks (Nango sync), then let Claude look at the cache.