MCP for Tax Firms: Connecting AI Assistants to Your Tools

A Preparer asks whether the Firm's AI assistant could read client documents straight from the document store instead of working from downloaded copies. Someone mentions MCP. A week later there's a list of requests: the document store, the shared drive, the task tracker.

Each of those is a decision about access, and the Firm makes it for each connection. The questions stay the same whatever sits on the other end. What can the connection reach? Which folders? What gets recorded? Who said yes?

This piece gives a Preparer, Reviewer or Firm manager a one-page check sheet for each connection, a short test on a Doe folder, and a list of changes that send the sheet back for review. It doesn't cover which assistant to pick or how to set one up. TracePrep's tax-prep plugin keeps the same line: the plugin drafts, the Firm's preparer prepares, the Reviewer signs off, and access is by waitlist.

Record the Firm's intended scope

When working from copies, the Firm can record which documents it intends to share. A Preparer can list the three documents selected for a proposed task.

For a proposed connection, the Firm can record its intended scope before deciding whether to proceed. The Firm can list its access questions and decide which answers it wants before approval. The Firm can ask what evidence it wants before accepting an answer to "what can it see?"

So the Firm can treat each connection like a new staff login to that tool: decided once, written down, and checked again when something changes.

Four questions before any connection

These four sit after the account question. Which account the assistant runs under, and what its terms say about client data, is covered in what an AI assistant does for a tax practice.

1. What can it reach, and can it change anything? Which parts of the tool does the connection open: documents, client records, messages, tasks? Then the harder half. Can the assistant only read, or can it also create, edit, move or delete? If the connector's own documentation doesn't say, the Firm can treat the answer as "it can change things" until someone confirms otherwise.

2. Which folders? Name them. "The client folders" isn't an answer. "A copy of the Doe Holdings folder for this period" is. If the tool can't limit a connection to named folders, the Firm decides whether that connection waits. The Firm can use a client-folder file index to list the documents it proposes to include.

3. What gets recorded? Ask what record exists after the assistant uses the connection: who made the request, what it touched, and when. Then ask where that record lives and who can read it. If there's no record, write "none" on the sheet. The Firm decides whether a connection with no record goes live at all.

4. Who approves it? The Firm can have one person sign the sheet and turn the connection on. The Firm picks who: a partner, the person who owns the tool, or whoever the Firm's own policy names. The Firm can ask a Preparer who proposes a connection to submit the sheet to its chosen approver before activation.

The connection check sheet

The Firm can keep one sheet per connection, in whatever format it already uses for internal checklists. Copy this table and fill one for each tool:

The sheet records the Firm's choices so the next person can read what was decided and why. On its own, it doesn't make a connection safe.

The Firm can keep the signed sheets together in one place to record each connection's approval status, requested scope and chosen approver. Under this approach, the Firm can withhold approval until its chosen approver signs the sheet.

Test it on a Doe folder first

Before a connection touches client work, the Firm can run it against a Doe practice folder, set up like a real client folder with made-up documents. The test can be short.

1. Ask the assistant to list what it can see through the connection. Compare that list to "Folders in reach" on the sheet.
2. Ask it to read one document and draft a short summary that names the page each point came from. A person checks the summary against those pages.
3. If the sheet says read only, ask it to rename a test document. The Firm can make an unchanged filename one condition for approval. If the test document's name changes, the Firm can record the result and withhold approval.
4. Open the record. Check that it shows the requests from steps 1 to 3, who made them, and when.
5. Write the test date, the Doe folder and what the record showed on the sheet.

The Firm can choose to pause after an unexpected result and return the sheet to its approver.

When to check again

The Firm can choose when to revisit an earlier approval. The Firm picks the changes that send the sheet back to the approver. One starting list: the tool adds a feature or changes its settings, someone widens the folders in reach, the read-or-change answer changes, the assistant or the account it runs under changes, or the approver leaves the Firm.

The Firm can document its chosen responsibilities alongside the connection decision. The Firm's preparer prepares, and the Firm's Reviewer signs off. Where the line sits between a draft and a professional's conclusion is its own question, covered in AI drafts, professionals sign.

A Doe example

The names and details below are made up for illustration.

Jane Doe, a Preparer at Doe & Co. CPA, wants the Firm's AI assistant to read client documents straight from the Firm's document store. She fills in a check sheet.

Requested scope: Jane lists Doe practice documents and marks client messages as excluded from her request. Read or change: Jane requests read-only use and records the questions she wants answered before approval. Folders requested: Jane lists one copy of the Doe Holdings practice folder and marks all other folders as excluded from her request. Record requested: Jane asks what records are available, whether they identify the requester and time, and whether they include the request text.

She runs the test on the Doe Holdings copy. She compares the returned list with the sheet and records any differences. She checks any page references in the response against the practice documents and records missing references. She records whether the practice document's name changed. She compares any available record with her three test requests and notes missing entries.

Pat Doe, the partner the Firm named as approver, reads the sheet. She adds one line under "Folders kept out": the Firm's own payroll folder, which sits next to the client folders in the store. She asks Jane to rerun step 1, compare the response with the requested exclusions and record any differences. Jane records the response, and Pat decides whether to request further checks. Pat signs and dates her approval of the requested scope, then decides whether to authorize activation.

Two months later the document store adds a new sharing feature. Under "Re-check when", that's a trigger. Jane sends the sheet back to Pat before she uses the connection again. Pat checks whether the new feature widens what the connection can reach, updates the sheet and signs it again.

Where TracePrep fits

We've built a TracePrep plugin that drafts these steps in your Firm's workflow, while your preparer decides and your Reviewer signs off. Join the waitlist and we'll tell you when plugin access opens.

Get on the list for plugin access

This is general information, not tax or legal advice. In TracePrep's workflow, the plugin drafts, the Firm's preparer prepares, and the Firm's Reviewer signs off. Access to the plugin is by waitlist. Keep client data inside the systems your Firm has approved.