Connecting Claude or ChatGPT to your books with MCP

Comma exposes its full accounting surface as a remote Model Context Protocol (MCP) server. Connect Claude, ChatGPT (developer mode), or Claude Code, and the assistant can read reports, categorize transactions, draft invoices, and reconcile the bank feed — by calling well-defined tools, not by scraping a screen.

An assistant never gets more access than the person who connected it. Every tool call is checked against that user's current role on each request, so changing a role or disconnecting a connector applies to the very next action, not eventually.

Connecting always shows an explicit consent screen naming what's being requested and which company. Every action lands in your audit trail, and you can revoke access in one click — active sessions stop working immediately.

Because the assistant operates through a controlled interface with permissions and a full audit trail, it's working with the actual ledger — not a pile of pasted numbers. And because the ledger is immutable, nothing it does can silently rewrite history: corrections are still voids and reversals.