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Connect AI Assistants (MCP)

MCP is the standard that lets an AI assistant such as Claude, ChatGPT, Cursor, or Codex work with another product. Once connected, you can ask your assistant about your books in plain English, and it can make changes only within the limits you approve. There are two directions: your assistant reaches into DayZero (most people), or DayZero's own assistant reaches out to other servers.

Key capabilities

  • Connect Claude, ChatGPT, Cursor, Claude Code, or Codex with one server address and a normal DayZero sign-in; no key to copy
  • Ask about balances, invoices, bills, transactions, reports, and the month-end close, or have the assistant categorize, draft, and reconcile
  • Risky actions (sending or voiding invoices, payments, journal entries, bulk edits, deletes) pause for your approval
  • A list of Connected apps with what each can do, when it was last used, and a Disconnect button that cuts it off at once
  • A Proposed Changes queue for edits an assistant prepared but left for a person to approve
  • The other direction: connect outside servers (payroll, billing, project tools) so DayZero's assistant can use their tools, with per-tool blocking

How it works

You sign in to DayZero in your browser and review what the app asks for: viewing data, making changes, or both. The assistant then acts as you, with your access to each business. A viewer-level role can read but never change.

flowchart LR
  ai["Your AI assistant"] -->|"Sign in and allow"| dz["DayZero"]
  dz -->|"Reads"| answer["Answers and reports"]
  dz -->|"Risky change"| ask{"You approve?"}
  ask -->|"Yes"| done["Change made"]
  ask -->|"No"| stop["Nothing changes"]

How to use it

  1. Open Settings > Developers and find Connect an AI assistant.
  2. Pick your assistant: Add to Claude, Copy URL for ChatGPT, Add to Cursor, or copy the Claude Code command or Codex setting. Every one uses the same server address.
  3. Sign in to DayZero when the browser opens and review what the app asks for. The screen lists what the app can read, with an Allow changes checkbox if it wants to create and edit records (untick it for read-only). If you have more than one business, choose All businesses you can access or Only one business: a connection limited to one business is refused for every other business. Connected apps later show these as View data, Make changes, and Stays signed in.
  4. Ask a question. If you have several businesses, the assistant asks which one to use, and you can say "switch to" another at any time.
  5. When a confirmation appears for a change, check the business and amounts, then approve or decline.
  6. Review connections under Connected apps on the same page. Use Details for permissions and dates.
  7. To revoke access, click Disconnect and confirm. The app loses access immediately; you can reconnect later.
  8. To let DayZero's assistant use another server, open External MCP servers and click Connect a server (owners and admins only).

Pro tips

  • Read the permissions on the sign-in screen. If an app only asks to view data, it cannot change anything.
  • Check Connected apps now and then. An app marked Inactive (unused for over 30 days) is a good one to disconnect.
  • Some apps (Cursor, Codex, claude.ai, and some Claude Code hosts) cannot show a confirmation pop-up. There the assistant gives you a link; open it while signed in to DayZero, review the change, and choose Approve or Decline. Saying yes in the chat is not enough, and the assistant cannot approve for you. An approval covers that one action and expires after 30 minutes.
  • Changes an assistant queues for a person to review appear in Proposed Changes as Waiting for approval; nothing changes until someone approves.
  • Connections are separate from API keys: disconnecting an app never affects a key, and a key cannot sign in an assistant. See Developers & API Access.

In-depth guide

What an assistant can read and change

It sees the same businesses and data you do: transactions, invoices, bills, customers, vendors, reports, reconciliations, and close status. Changes cover categorizing, editing, and creating records, plus reconciliation and period tasks, all subject to your role. Advisory firm staff can also ask cross-client questions.

Approvals

Most reads and previews run freely. Actions that move money, send or void documents, post journal entries, delete, or change many rows at once ask first, either in a pop-up or, in apps without one, on an approval page in DayZero that you open from a link. A decline leaves your books untouched. A grant you gave with "Always allow" in DayZero's own assistant can let that action skip the prompt for that business, but deletes and irreversible actions always ask.

Sign-in and access

Anyone with a DayZero login can connect an assistant, with no separate approval. If your firm switched off API access for you, sign-in is refused; ask a firm admin on the Team Members page. Connections persist until you disconnect them.

Connecting outside servers to DayZero's assistant

On the External MCP servers page, Connect a server asks for a Name and Server URL, then either Sign in with the provider or API key or no sign-in. Connections are shared by the whole business, and only owners and admins can change them.

  • Each server shows Connected or Needs attention, an Enabled switch, and its tools. Use Reconnect, Update API key, Refresh tools, or Disconnect.
  • Each tool is labeled Read (no approval), Needs approval, or Blocked. Use Block to stop a tool and Unblock to allow it again.
  • Trust read-only hints is off by default. Turn it on only for servers you trust, since it lets tools the server calls read-only run without asking.

For setup details for developers, see the MCP guide.